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Author Topic: I'm still trying to understand how all this works so..  (Read 2259 times)

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Offline Esquare

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I'm still trying to understand how all this works so..
« on: January 14, 2007, 01:25:20 AM »
my question is what is going on with the HIV that hides in the reservoirs that can't be reached by HAART? Assuming someone is undetectable due to HAART therapy the virus is successfully supressed in the blood but not in the reservoirs like the gut. What is HIV up to when it is in those areas? Is it still doing its thing with replicating on cd4 cells that are there? Do we know yet?

I'm just trying to understand as much as I can about the virus.

Offline bimazek

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Re: I'm still trying to understand how all this works so..
« Reply #1 on: January 15, 2007, 09:21:27 PM »
my understanding is that the anti retro go thru out the body in the blood stream and then into the nucleus of every cell and throw a wrench into the replicating of the virus, but 98% of virus is in gut and  is not in blood only 2% in blood, in the gut there is constant work to figure out what is good stuff and bad, good is vit. min. aminos, etc, sometimes a bug gets in, i think that the gut is like a wound or womb in the sence that it was absorb nutrients and kind of be semi permiable so that is a very very stressful situation, in otherwords to open itself up to absorbing molecules and sorting which are good, takes alot of energy and repair, imagine if you had to rub your oranges into your skin, to digest them, it would be tramatic for the skin, so the gut cells have to be replaced every three days, well, why isnt haart effective in the gut, there are some breakthrus in finding out why, mostly it is in the inflamation process of this healing and rejuvinating and recreating the cells every 3 days that takes place, the inflamation, and oxidation of this area is great compared to a bone, which just kind of sits there, so in an area of body which is contantly being re created rebuilt, there is more inflamtion, more chances for such things

do a google scholar search on "hiv gut inflammation"


Offline bimazek

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  • Posts: 781
Re: I'm still trying to understand how all this works so..
« Reply #2 on: January 15, 2007, 09:24:39 PM »
another thing i just thought of is the acid, the tremendous acidic-stress that the cells in the stomach and intestine have to endure to survive and that is also why they have to be replaced and possibly why meds allow the resevour to exist there, imagine all the repair so that give hiv chance to replicate, perhaps that is why the one science paper suggested hiv perople take anti inflamitory meds


Offline bimazek

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  • Posts: 781
Re: I'm still trying to understand how all this works so..
« Reply #3 on: January 15, 2007, 11:21:29 PM »
gut is continueous bombarded by dietary antigens
meaning food this is from one of these papers below

should we all be on....
Thalidomide treatment reduces the alteration of paracellular barrier function in mice ileum during … - group of 4 »
E Mazzon, S Cuzzocrea - Shock, 2006 - shockjournal.com
... the epithelium is in constant interplay with luminal bacteria, dietary antigens,
and with ... R, Zeitz M, Pauli G, Schulzke JD: Supernatants of HIV-infected immune ...
Cited by 1 - Related Articles - Web Search - BL Direct

Role of regulatory T cells in human diseases - group of 3 »
TA Chatila - The Journal of Allergy and Clinical Immunology, 2005 - Elsevier
... results suggested that mucosal induction of tolerance against dietary antigens is
associated ... 117 In HIV infection CD4 + CD25 + Treg cells inversely correlate ...
Cited by 14 - Related Articles - Web Search

HIV-1 in semen: an isolated virus reservoir - group of 5 »
RA Byrn, D Zhang, R Eyre, K McGowan, AA Kiessling - J Virol, 1996 - naturopathyworks.com
... semen HIV-1 does not arise from the same reservoir of infection ... We determined
HIV-1 protease-gene sequences of infectious virus recovered ... Gut 1995; 37: 449–54 ..


Macrophage HIV-1 infection and the gastrointestinal tract reservoir - group of 8 »
PD Smith, G Meng, JF Salazar-Gonzalez, GM Shaw - 219 - Soc Leukocyte Biology
... macrophages a prominent role as a HIV-1 reservoir. ... In vertical transmission,
HIV-1 is inoculated into the ... or infant likely enters the gut-associated lymphoid ...

HIV-1 Protease Inhibitors and the MDR1 Multidrug Transporter - group of 3 »
CGL Lee, MM Gottesman - 1998 - Am Soc Clin Investig
... of potential Pgp substrates in the gut and brain ... 1997) Recovery of replication-competent
HIV despite prolonged ... et al (1997) Identification of a reservoir for HIV ...
Cited by 33 - Related Articles - Web Search - BL Direct

The mucosal immune system and HIV-1 infection - group of 5 »
R Veazey, A Lackner - AIDS Rev, 2003 - aidsreviews.com
... and may be the major viral reservoir, even in ... In considering the gut-associated lymphoid
tis- sues, it ... Lackner: The Mucosal Immune System and HIV-1 Infection ...
Cited by 21 - Related Articles - View as HTML - Web Search


Alterations in intestinal permeability - group of 4 »
MC Arrieta, L Bistritz, JB Meddings - Gut, 2006 - Br Soc Gastroenterology
... of autoimmune disease we now have evidence for a dietary antigen and an ... absorptive
capacity, intestinal permeability and jejunal histology in HIV and their ...
Related Articles - Web Search


Importance of gastrointestinal ingestion and macromolecular antigens in the vein for oral tolerance … - group of 4 »
A Wakabayashi, Y Kumagai, E Watari, M Shimizu, M … - Immunology, 2006 - Blackwell Synergy
... Although the gastrointestinal tract is incessantly exposed to dietary antigens and
commensal micro ... Transepithelial transport of HIV-1 by intestinal M cells: a ...
Related Articles - Web Search




Probiotics in humans–evidence based review - group of 2 »
K Harish, T Varghese - Calicut Medical Journal, 2006 - openmed.nic.in
... of intestinal barrier function • Controlled transfer of dietary antigens • Stimulation
of ... might be effective in some subjects with HIV-related chronic ...
Related Articles - View as HTML - Web Search



mmune privilege: a recurrent theme in immunoregulation? - group of 2 »
AL Mellor, DH Munn - Immunological Reviews, 2006 - Blackwell Synergy
... gut: the establishment and maintenance of nonresponsiveness to dietary antigens
and commensal ... Persidsky Y, Poluektova L. Immune privilege and HIV-1 persistence ...
Related Articles - Web Search




Elemental and Semi-Elemental Formulas: Are They Superior to Polymeric Formulas?
D Makola - PRACTICAL GASTROENTEROLOGY, 2005 - healthsystem.virginia.edu
... chemically syn- thesized amino acids that are entirely antigen free thus limiting
the patient’s exposure to dietary antigens that may ... HIV Related Disease ...
Related Articles - View as HTML - Web Search - BL Direct




Immunologic Research - group of 10 »
F Inside - Immunologic Research, 2005 - journals.humanapress.com
... CTL in the Gastrointestinal Mucosa Models of rotavirus and HIV infection have given
the greatest insight into the importance of gas- trointestinal CTL responses ..


Multiple measures of HIV burden in blood and tissue are correlated with each other but not with clinical parameters in aviremic subjects.

CLINICAL SCIENCE
AIDS. 17(1):53-63, January 3, 2003.
Anton, Peter A a; Mitsuyasu, Ronald T a; Deeks, Steven G b; Scadden, David T c; Wagner, Bridget d; Huang, Christine e; Macken, Catherine f; Richman, Douglas D g; Christopherson, Cindy h; Borellini, Flavia j; Lazar, Richard j; Hege, Kristen M j

Abstract:
Objectives: To determine the levels of residual HIV DNA and RNA in blood and gut reservoirs in aviremic patients, assess correlations among compartmental measurements of HIV burden, and evaluate association with clinical parameters.

Design: Cross-sectional analysis of baseline data only, on 40 patients enrolled in phase II study evaluating efficacy of autologous gene-modified CD4+ and CD8+ T cells. All patients were on stable antiretroviral regimen with undetectable plasma HIV RNA (< 50 copies/ml).

Methods: Measurements repeatedly performed over 8-12 weeks pre-intervention: blood HIV DNA, analysis of rectal mucosa-associated lymphoid tissue for both HIV RNA and HIV DNA, and quantitative co-culture of HIV from CD8-depleted peripheral blood mononuclear cells (PBMC).

Results: Quantifiable levels of HIV detected in compartments despite undetectable levels of plasma HIV RNA: HIV co-culture of PBMC (88%), blood HIV DNA (95%), rectal biopsy HIV DNA (95%), rectal biopsy HIV RNA (65%). A significant correlation existed among various measures of HIV burden (HIV co-culture, blood HIV DNA, rectal biopsy HIV RNA and DNA) but not between assays and clinical parameters [duration of highly active antiretroviral therapy (HAART), type of HAART]. All assays had comparable or less variability than in plasma viral load assays; HIV co-culture had the highest coefficient of variability whereas the blood HIV DNA assay had the lowest and was considered the most reliable assay.

Conclusions: The data support safety, feasibility and high compliance of quantifying reservoirs of residual HIV in treated subjects with undetectable plasma HIV RNA. Lack of correlation between levels of HIV in residual reservoirs and duration of HAART suggests treatment-mediated viral suppression alone does not lead to reproducible decay in HIV reservoirs.

Using highly active antiretroviral therapy (HAART), it is now possible to reduce plasma HIV-1 RNA to undetectable levels [1]. In addition to the pronounced effect on HIV-1 viremia, clinical trials have now shown that combination antiretroviral therapy (ART) delays disease progression and prolongs life [2,3]. Although healthy, asymptomatic patients with normal levels of CD4+ T cells often have low levels of plasma viral RNA, active viral replication and T-cell turnover is still present in lymph nodes [4,5]. Recent studies have demonstrated that viable, replication-competent virus persists for at least 2 years in the face of HAART, despite complete suppression of HIV-1 RNA in blood and in some cases, lymphoid tissue [6-8]. Assays to detect HIV-1 RNA and DNA levels in lymphoid tissue have recently been described and these assays can now be used to follow the status of HIV infection in these tissues [9-12]. What has not been clarified is the degree to which quantified levels of virus in compartments correlate with and possibly predict clinical status and whether these measures may function as surrogate markers in clinical trials and/or care.

As the gut is the largest lymphoid organ in the body and a known reservoir for HIV, it is reasonable to investigate this compartment as a readily accessible source of lymphoid tissue in subjects with undetectable plasma viral load. The interest in quantifying viral burden of gastrointestinal-associated lymphoid tissue (GALT) HIV RNA and HIV DNA is compounded by the enhanced vulnerability to HIV infection of lymphocytes at this site compared to circulating peripheral blood mononuclear cells (PBMC) [13,14] based on activation state, memory phenotypes, expression of HIV coreceptors, and increased levels of soluble inflammatory mediators (e.g. tissue chemokines) [15].

We have recently completed a phase II study to evaluate the efficacy of autologous CD4-zeta gene-modified CD4+ and CD8+ T cells in HIV-infected subjects with undetectable plasma HIV RNA (< 50 copies/ml) and CD4+ cell counts > 200 × 106 cells/l on HAART for > 6 months [16]. Such subjects have been estimated to have a total body load of latently infected CD4+ T cells with replication-competent HIV of < 107 cells [11]. The virologic endpoints of the trial focused on quantitation of reservoirs of HIV-infected cells in blood and lymphoid (mucosal) tissues before and after cell infusions and is reported elsewhere [16]. Assays at baseline and throughout the trial included measurement of HIV DNA in blood, analysis of rectal mucosa-associated lymphoid tissue for changes in viral burden (both HIV RNA and HIV DNA), and quantitative co-culture of HIV from CD8-depleted PBMCs using an enhanced limiting dilution co-culture assay [6].

We now report the results from baseline, steady-state, quantitative measurements of HIV burden using five assays in blood and gut compartments. Our primary objective in this analysis was to assess the relationship between viral burden in a variety of long-lived cellular reservoirs, and to describe the relationship between virus burden and clinical status (years of HIV infection, duration of antiviral therapy and CD4+ cell count). Our secondary objective was to determine the feasibility of using novel assays for measuring outcome in patients without detectable plasma viremia.

Offline bimazek

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  • Posts: 781
Re: I'm still trying to understand how all this works so..
« Reply #4 on: January 15, 2007, 11:21:44 PM »
Discussion TOP

Antiretroviral therapy prevents de novo infection and inhibits viral replication but does not eradicate long-lived cellular reservoirs of virus. Immune based therapies that are cytolytic and have the potential to eradicate virus from latent cellular reservoirs may be necessary for viral eradication. Reports have suggested that replication competent HIV can be isolated from the vast majority of patients with prolonged plasma virus suppression, confirming that residual HIV reservoirs remain [11,19,20]. Assessments of these reservoirs with reliable and reproducible methods with minimal variability are critical in providing measurable endpoints for adjunctive therapies aimed at further reducing total body viral burden.

In this assessment of steady-state measurements of viral reservoirs, the vast majority of subjects had quantifiable levels of HIV measured using the HIV co-culture (88%), blood HIV DNA (95%), and rectal biopsy HIV DNA (95%) assays. Furthermore, most patients (65%) had detectable levels of HIV RNA in rectal biopsies despite having undetectable levels of HIV RNA in plasma. The procedure for obtaining rectal biopsies is relatively painless, fast, has few complications and allows for frequent sampling [21]. An important observation in this trial is the high degree of adherence to the invasive procedures performed (100% of 80 baseline and 97.5% of the entire study's 200 scheduled flexible sigmoidoscopies).

Eradication efforts need to address these mucosal tissue sites directly as such tissues may continue to foster low-level replication due to, among other factors, the inherent difference in susceptibility to infection of GALT T cells compared with PBMC [13,14], the increased activation status of the resident lymphocytes and the presumed, although not documented, lower concentrations of antiviral drugs in tissue than in plasma. This latter point is suggested by reports of isolated cases of slightly different HIV resistance panels in gut- and blood-derived virus, despite the majority of isolates having concordant profiles [15]. Regardless of the pathogenic variables, the demonstration of persistent viral detection in the mucosal compartment of aviremic subjects coupled with the documentation by co-culture that the presence of PBMC-associated viral DNA sequences was significantly correlated with replicating virus, suggests that at least a fraction of the mucosal viral RNA and DNA reflects replication-competent HIV. To confirm the presence of replication-competent HIV in GALT in aviremic patients, mucosal HIV co-culture assays would be necessary. However, such assays are not available and would be technically challenging due to the large numbers of lymphocytes required.

However, one can use the acquired information to make rough estimates of the percentage of HIV DNA in PBMCs that reflects replication-competent versus non-replicative DNA by comparing the number of copies of HIV DNA detected in PBMC with the number of infectious units (cells) determined by the limiting dilution co-culture assay. With the assumption that 1 μg DNA reflects 150 000 cells, comparison of the number of PBMC with HIV DNA with the number of PBMCs with infectious virus demonstrates a two to three orders of magnitude greater number of HIV DNA-containing cells than infectious virus-containing cells. This suggests that in PBMC, ∼ 99.9% of detectable HIV DNA is of non-replicative potential (under the stimulating co-culture assay). Nevertheless, it also demonstrates that infectious potential remains. In viewing the gut environment, it is plausible to imagine low-level replication and maintenance of infection given the proximity to highly vulnerable cellular targets. Even without having tissue co-culture data to support this, the blood analysis suggests that there may be sufficient infectious potential of residual HIV in the gut to implicate GALT as an important reservoir of latent infection.

There was a significant correlation between the various measures of HIV burden (HIV co-culture, blood HIV DNA, rectal biopsy HIV RNA and DNA) suggesting that these are interrelated measures of total body HIV burden. However, there was no significant correlation between HIV reservoir assays and clinical parameters including duration of HIV infection, ART or HAART usage or number of CD4+ T lymphocytes. A curious exception to this was the isolated inverse correlation between HIV tissue RNA level and years of HIV infection although the relevance of this is unclear given the multiple statistical analyses performed. Given the small sample size in this study no attempt was made to make statistical adjustments for the variation in the number of data-points available for each assay or the multiple univariate correlations performed. However, given the multiple associations across all reservoir assays and the relative lack of association between reservoir assays and clinical parameters, it is unlikely that these observations are due to chance alone.

There was no significant correlation between tissue HIV RNA and years of any ART exposure. The lack of correlation between levels of HIV in residual blood and tissue reservoirs and patient clinical characteristics supports previous published data focused on quantitative HIV co-culture data only in a smaller cohort of patients [7]. Our analysis extends this previous observation to include measures of both blood and gut mucosal reservoirs and suggests that HAART therapy alone does not lead to a reproducible decay in HIV reservoirs; other factors such as host immune response, viral fitness, size of reservoirs, tissue penetration etc. are likely to be important co-factors that need to be addressed in future efforts to reduce viral reservoirs [19,22-24].

Under optimal treatment conditions, approximately 90% of the HIV-infected population undergoing therapy with HAART can be rendered aviremic, at least for a period of time [1]. Given that such therapy is now generally accepted to be incapable of eradicating HIV infection, new surrogate endpoints are needed to evaluate the next generation of HIV therapeutics designed to eliminate these residual reservoirs of virus. The assays employed here were evaluated with this in mind. A reliability analysis was carried out for each of the assays (HIV co-culture, blood HIV DNA, rectal biopsy HIV DNA, rectal biopsy HIV RNA) based on two or more baseline values to determine whether such assays are reliable with low variability and, therefore, potentially suitable for use as surrogate efficacy endpoints in trials in patients with undetectable plasma viremia. This analysis was based on the assumption that the multiple values taken over an 8-12 week period in this well-characterized population prior to initiation of a clinical trial represented steady-state levels of viral burden. All assays studied had comparable or less variability than that seen in currently used plasma viral load assays. HIV co-culture had the highest coefficient of variability whereas the blood HIV DNA assay had the lowest coefficient of variation and was considered to be the most reliable assay. The variability in the HIV co-culture assay was similar to that of current plasma viral load assays in clinical use.

The inherent virologic failure rate in subjects who initially achieve an undetectable plasma viral load on HAART and are maintained on optimal regimens is estimated at 4% over 16 weeks. This failure rate may be higher in those with prior history of suboptimal regimens, those with higher pre-treatment viral loads, or longer time to initial viral suppression [25]. Patients successfully treated with HAART may have transient 'blips' in viral load (defined as transient increase in plasma HIV RNA to > 50 copies/ml at isolated time-points). During the pre-treatment period for this clinical trial, eight subjects experienced viral load 'blips'. Such subjects might reflect a different immunologic and virologic cohort. However, when a subset analysis was performed on these two virologic cohorts (persistently undetectable and transient viral blips), no new correlations between clinical parameters and viral reservoirs emerged. Similarly, when we retrospectively assessed the ART history of the subjects prior to the study's 6 month pre-screening period as to whether it was 'optimal' or 'sub-optimal' and then evaluated if either sub-group's clinical parameters correlated with their viral reservoirs, no new patterns emerged. Interpretations of these results are stronger in that there were 20 subjects in each group and suggest that the extent of antiviral coverage does not reflect differently in viral reservoirs. In addition, there was no evidence of increased viral burden in blood and gut compartments in those with periodic plasma viral blips. Taken together, whether the antiviral regimen was fully suppressive or of optimal design did not yield any clinically relevant correlates with viral activity and reservoir reserve.

Plasma viral load may not provide information regarding tissue HIV reservoirs nor residual viral activity in patients responding well to HAART. Thus, there is a need for additional efficacy endpoints for trials assessing the impact of antiviral regimens in subjects with undetectable viremia on HAART. As plasma viral load proved to be an important surrogate of clinical activity of antiviral regimens in those with detectable plasma viral burden, once levels fall below detection in plasma, sampling from those tissue sites shown to have persistent viral presence will need to be assessed. Monitoring of rectosigmoid tissue viral burden may prove to be a useful biologic surrogate endpoint with low assay and intra-subject variability and excellent patient compliance [12] for use in future intervention trials in aviremic subjects. The procedure is minimally invasive and may identify changing viral and immune parameters that may be unappreciated when sampling blood alone, as exemplified at the conclusion of this clinical trial in which reductions in gut HIV DNA, but not blood HIV-DNA were demonstrated following infusion of gene-modified HIV targeted T cells (results reports elsewhere) [16]. Blood HIV DNA measurements may also be a useful parameter to follow and demonstrated the greatest sensitivity and reliability in this study but again, may not accurately reflect the tissue dynamics during treatment [16]. Although scientifically interesting and the only assay to directly measure the replication capacity of residual HIV, quantitative HIV co-culture assays are laborious and expensive and, therefore, not feasible for large clinical studies.

The data presented here support the feasibility of the described assays in quantifying HIV in various compartments and demonstrate their inter-relatedness in subjects with undetectable plasma HIV. The rectal biopsy HIV RNA assay had the lowest sensitivity, HIV co-culture assay the highest variability and blood HIV DNA the lowest variability. While the assays did correlate with each other, the degree of viral burden in these different compartments did not correlate with clinical parameters. Therapeutic strategies aimed at eradicating HIV in both early-stage disease and in those with undetectable plasma viral load will need to be active in mucosal lymphoid tissue where the majority of HIV replication is taking place. These assays can be used to follow the status of HIV infection in different tissues but shed no illumination on distinguishing clinical factors contributing to the size of the residual viral reservoir in fully suppressed patients. The size of these reservoirs is not clearly correlated with historical clinical descriptors. Whether they emerge as predictors of future clinical course remains to be seen.

Offline bimazek

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  • Posts: 781
Re: I'm still trying to understand how all this works so..
« Reply #5 on: January 16, 2007, 09:08:40 PM »
scientific papers online about hiv and i did a search on 2007 hiv papers, there are 87 so far.  This one really stands out!
 
*2007
 
*new cd4 cells die in the lymph nodes not in the blood but specifically in the lymph nodes of the gut
 
*but the loss in the gut lymph nodes is not mirrored in the blood or other lymph nodes
 
*which explains why blood cd4 counts do not give a whole picture of the person and what he is facing
 
*also strangely uninfected nearby bystander cd4 cells die --- not the hiv infected ones
 
*FasL anti-body would block this process - sounds like breakthrough to me
 
*only one cd4 cell in 1,000,000 is producing virus, very few of them is infected
 
*hiv is a disease of the homing of the cd4s back to the nodes to be distroyed, the body thinks it has cleared the infecton
after the 2 week initial burst or the chronic fight and then cytokines that home the cds back to the nodes are relesased this tricks the cd4s to go back to nodes and some other molecule switch tells the cd4s to aposisis the un-infected cd4s in the nodes
 
A HOMING RECEPTOR ON OUTSIDE OF UNINFECTED CD4 CELLS GETS TURNED ON BY BEING CLOSE TO OR TOUCHING AN HIV PARTICLE (BUT NOT INFECTED BY IT) THIS CAUSES THE CD4 TO HOME BACK TO THE LYMPH NODE TO KILL ITSELF CALLED APOSISOS...
 
so the disease is actually a disease of the uninfected cells dying
the cd4s that are dying ARE NOT INFECTED
we loose cd4s that are not even infected!!!
this is a huge breakthru if you ask me...
 
sure
 
when you get a flu there is that awful giant wave of immune response and all those terrible chemicals cytokines and bugs being killed off
then the immune system pulls back and says, did i get it all, and then it hits with another wave, then pulls back, and then
says ok i finished and i have to put away all the tanks and big guns and rifles...  thats when the cells get called back to the nodes
that means...
 
that is the period called homing back to the lymph nodes
 
so something wierd is happening in hiv disease because the body thinks the infection has been dealt with then
it calls back the cd4s into the nodes and because they have touched or recieved a signal -=BUT ARE NOT INFECTED OR NOR WILL THEY BE INFECTED-
THEY do aposisos and they die and that is why cd4s deplete
 
it is not the infected ones that die off!!!!
 
also this explains why all those weird alternative therapies though they dont stop it can have some minor effects
 
anything that disrupts the homing of the uninfected cd4s back to the node to aposisos or self die.
 
it all has to do with the FasL --- some chemical in immune system
CD62L is also involved
 
the cool thing is with a anti-FasL monoclonal antibody... which is big time expeimental stuff real complicated to create
they can stop the FasL induced death of the cd4s
 
listen they just figured out which and how the cd4s where dying off a few weeks ago.. before they thought the infected ones were dying
 
now they find out more
 
only the CD62L receptor tells the poor uninfected cd4 cell to go home
but it may be that CD62L and a few other receptor switches get turned on once in the node and the poor cell is told to die off
your job is done
 
 
http://www.jleukbio.org/cgi/rapidpdf/jlb.0506338v1.pdf
 
The hallmark of HIV-1 disease is the
gradual disappearance of CD4 T cells from the
blood. The mechanism of this depletion, however,
is still unclear.
 
Evidence suggests that lymphocytes
die in lymph nodes, not in blood, and that uninfected
bystander cells are the predominant cells
dying. Our and others’ previous studies showed
that the lymph node homing receptor, CD62 ligand
(CD62L), and Fas are up-regulated on resting
CD4 T cells after HIV-1 binding and that these
cells home to lymph nodes at an enhanced rate.
During the homing process, signals are induced
through various homing receptors, which in turn,
induced many of the cells to undergo apoptosis
after they entered the lymph nodes. The purpose of
this study was to determine how the homing process
induces apoptosis in HIV-1-exposed, resting
CD4 T cells. We found that signaling through
CD62L up-regulated FasL. This resulted in apoptosis
of only HIV-1-presignaled, resting CD4 T
cells, not normal CD4 T cells. This homing receptor-
induced apoptosis could be blocked by anti-
FasL antibodies or soluble Fas, demonstrating that
the Fas-FasL interaction caused the apoptotic
event. J. Leukoc. Biol. 81: 000–000; 2007.
 
 
Steroids, which are known to down-regulate CD62L and retard
lymph node homing, have been shown to stop reduction of CD4
cells in the blood of patients  This may be the consequence
as control of aberrant homing signals for the marked
reduction in apoptosis. Future studies, testing whether inhibition
of lymph node homing or homing receptor induction of
apoptosis would prevent depletion of CD4 cells in patients,
are needed.

One of the
major observations in this study is that apoptosis of HIV-1-
exposed, resting CD4 T cells, in which CD62L was crosslinked,
could be inhibited significantly by blocking anti-FasL
antibodies or sFas (Fig. 4). This indicated that apoptosis of
HIV-1-exposed, resting CD4 T cells, subsequently signaled
through the homing receptor, is Fas-FasL-mediated. It is interesting
that apoptosis was detected in resting CD4 T cells
exposed with X4 virus strain (HIV-1213) or R5 virus (HIV-1BaL)
strain, subsequently signaled by XLCD62L, indicating that this
is a common property of HIV-1 (Fig. 2). Furthermore, such
effect seems to be independent of HIV-1 replication, as UVinactivated,
HIV-1-exposed, resting CD4 T cells, upon
XLCD62L, underwent apoptosis as well (data not shown).
 

Based on
our data, we proposed that in vivo, CD4 T cells are infected
with HIV in Peyer’s patches, where they may get the signals for
homing fast and up-regulated Fas and get the further signals,
such as FasL, through interaction between homing receptors
and their ligand on lamina propria and finally, undergo apoptosis
in lamina propria. We are currently working on the
effects of HIV on gut homing receptor  4
7 and consequence
of cross-linking of  4
7 on the HIV-exposed CD4 T cells
 
 
 
With respect to the in vivo relevance of our findings in the
context of HIV-1 pathogenesis, our data implicate the following
scenario to be operative in vivo and may act as a mechanism for
the death of uninfected CD4 cells. Resting CD4 lymphocytes
in lymphoid tissues (in gut, lymph nodes, etc.), coming
into contact with HIV-1 virions, productively infected cells, or
HIV-1-coated, follicular dendritic cells, result in induction of
a partially activated phenotype, including up-regulation of
homing receptors and Fas. Because of normal lymph node/
blood circulation, in which most lymphocytes in lymphoid
tissues migrate back to the blood within 2 days [56], many of
these cells will end up back in the blood at the time of
maximum-induced expression of homing receptors. These cells
would then home rapidly to peripheral lymph nodes or gutassociated,
lymphatic tissue, dependent on the type of homing
receptors (e.g., CD62L for peripheral lymph nodes;  4
7 for
gut). Following transendothelial migration, these CD4 T cells
receive signals through homing receptors, resulting in induction
of FasL expression on some of the cells and rapid susceptibility
 

Consequently, together
with the increased Fas expression within the same
CD4 T cell population, approximately one-third of them
would be depleted, and they do not produce HIV-1 [18]. In
support of this review, features that are characteristically associated
with HIV-1 infection include the following. As CD4
lymphocytes disappear in the blood, their numbers do not drop,
and the CD4/CD8 ratios do not invert in lymph nodes until late
in disease [57]; there is increased apoptosis of uninfected cells,
mainly localized in lymph nodes or gut-associated lymphatic
tissue [6, 45, 58] but not in the blood [59, 60]; there is
increased FasL-expressing cells with the morphology of macrophages
and lymphocytes, and the degree of FasL in vivo has
been shown to be correlated with the degree of apoptosis [61].
 
Steroids, which are known to down-regulate CD62L and retard
lymph node homing, have been shown to stop reduction of CD4
cells in the blood of patients [62]. This may be the consequence
as control of aberrant homing signals for the marked
reduction in apoptosis. Future studies, testing whether inhibition
of lymph node homing or homing receptor induction of
apoptosis would prevent depletion of CD4 cells in patients,
are needed.
ACKNOWLEDGMENTS
 
Steroids, which are known to down-regulate CD62L and retard
lymph node homing, have been shown to stop reduction of CD4
cells in the blood of patients [
 
Steroids, which are known to down-regulate CD62L and retard
lymph node homing, have been shown to stop reduction of CD4
cells in the blood of patients  This may be the consequence
as control of aberrant homing signals for the marked
reduction in apoptosis. Future studies, testing whether inhibition
of lymph node homing or homing receptor induction of
apoptosis would prevent depletion of CD4 cells in patients,
are needed.

 
Infection with HIV-1 is usually characterized by a gradual and
inexorable depletion of CD4 T lymphocytes. The importance
of the loss of these cells in the development of AIDS is
unquestioned, as it correlates with the loss of immune capabilities
and the consequent occurrence and severity of opportunistic
infections and HIV-1-associated neoplasms. However,
understanding the mechanisms by which HIV-1 causes CD4
T cell loss remains one of the unanswered questions in the
AIDS field. Many mechanisms have been proposed to explain
how HIV-1 causes depletion of CD4 T cells and the earliest
theorized that virus replication in CD4 T cells resulted in
their death or that virus-specific CTLs killed these infected
cells. However, elimination of productively infected cells could
not explain the significant loss of CD4 T cells [1], as few cells
in vivo are producing virus at any given time (approximately
one in 105 cells) [2, 3]. Recent studies suggest that depletion
of CD4 T cells mainly occurs in lymphoid tissues of the
gastrointestinal tract [4, 5], but the loss of these cells in the gut
is not mirrored in the blood and lymph nodes. In fact, CD4 T
cell depletion occurs in the “effecter area” of gut (lamina
propria) not in the “inductive area” (Peyer’s patches), where
most of the cells producing virus reside. It has also been shown
that increased numbers of CD4 cells are dying in peripheral
lymphoid tissues of HIV-infected subjects, but cells replicating
HIV-1 are not the principal cells dying; uninfected, neighboring
cells are dying [6]. Therefore, most theories about how
HIV-1 depletes CD4 T cells now depict ways uninfected
bystander cells can be eliminated. Some early studies indicated
that HIVgp120 binding to CD4 and CXCR4 receptors
induced apoptosis [7, 8]. All of these studies used transformed
cell lines, and studies using normal CD4 lymphocytes did not
find this phenomenon [7–11]. Also, the apoptosis induced in
cell lines was not Fas/Fas ligand (FasL)-mediated, but other
pathways were [7–9]. Recently, collagen deposition-associated
fibrosis and damaged lymphatic tissues that accompany immune
activation have been shown to be correlated inversely
with blood CD4 T cell count [4, 12]. Some studies suggest
that there is a significant dysregulation of cytokine responses,
which likely, influences T cell susceptibility to apoptosis [13].
Many of these factors may play some roles in CD4 T cell
depletion. However, excessive apoptosis of uninfected CD4 T
cells is thought to be the major reason for depletion of CD4
T cells [13, 14].
Our previous studies showed that HIV-1 binding to resting
CD4 T cells up-regulated the expression of CD62L, the
receptor for homing to lymph nodes, on some cells and enhanced
the homing of these cells from the blood into lymph
nodes [15–17]. Subsequent signaling through various homing
receptors during the homing process on these abortively infected
CD4 T cells induced many of them to undergo apoptosis
[16]. These signaling events occur when the cells transendothelial
migrate into lymph nodes, and it was shown that
CD4 T cells in the blood of HIV-infected people
 
 





Steroids, which are known to down-regulate CD62L and retard
lymph node homing, have been shown to stop reduction of CD4
cells in the blood of patients  This may be the consequence
as control of aberrant homing signals for the marked
reduction in apoptosis. Future studies, testing whether inhibition
of lymph node homing or homing receptor induction of
apoptosis would prevent depletion of CD4 cells in patients,
are needed.

IN THE LATE 80S AND EARLY 90S BEFORE good meds many hiv people seemed to prolong life somewhat
with steroids, perhaps this is the reason it worked

even today many hiv people take steriods for many reason

please comment...

my questions

what kind of steroids are the dr.s talking about?
what is the plan?
how big of a breakthru is this?





 
 
 
also
 
 
2007 hiv vaccines new book
http://books.google.com/books?hl=en&lr=&id=-m6H5kDm1JAC&oi=fnd&pg=PR7&sig=qGajLPO-zwTzLJs4einNA782HWc&dq=hiv#PRA2-PA56,M1

Offline Esquare

  • Member
  • Posts: 237
Re: I'm still trying to understand how all this works so..
« Reply #6 on: January 17, 2007, 01:17:23 AM »
Wow! Thanks Bimazek. I've got some reading to do. Thanks for all the time. I will comment after I process everything.

 


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