Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report a new suppressor function of CD8+ CD57+ lymphocytes from HIV-seropositive patients recipients, on the cytolytic activity of allospecific CTL, NK and LAK cells. This inhibitory effect is mediated by a non-antigen specific soluble factor distinct from PGE2, TGF beta and TNF alpha and beta. Biochemical characterization indicates that the CD8+ CD57+ inhibitory activity: 1) is heat and trypsin resistant but remains sensitive to pronase E hydrolyse, 2) specifically bind to concanavalin A-sepharose column, 3) is mediated by a 20-30 kdaltons glycoprotein.
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PMID:[Cytotoxic response against human immunodeficiency virus (HIV): control with suppressor factor]. 130 Dec 26

Cotton-wool spots and cytomegalovirus (CMV) retinitis are seen frequently in AIDS patients. Human immunodeficiency virus (HIV) infection of the retina has been proposed as a mechanism for the high incidence of retinal pathology. An autopsy study of the eyes from 25 consecutive cases of AIDS was performed using gross examination, light microscopy, trypsin digestion of retinal vasculatures, and immunohistochemistry to evaluate the possible role of HIV, as well as CMV, in the pathogenesis of retinitis and retinal vasculopathy. Brain tissue was studied in the first 20 of these cases to evaluate any correlation between retinal and central nervous system pathology. CMV retinitis was observed in 15 cases (60%). Cotton-wool spots were seen in nine cases (36%). CMV encephalitis was detected in four cases, whereas HIV encephalitis was noted in five cases. We were unable to demonstrate a correlation between CMV retinitis and CMV encephalitis. However, the number of cases studied was small, and the frequency of CMV encephalitis was low. On the other hand, bilateral CMV retinitis demonstrated a correlation to HIV encephalitis (P less than 0.005, Fisher's exact test). HIV infection of the retina was not detected by typical morphologic changes or immunohistochemistry. Immunohistochemistry localized CMV infection solely to areas of active retinitis. These findings suggest that bilateral CMV may serve as a marker of HIV encephalitis, possibly indicating a severely immunodepressed state.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of HIV and CMV in the pathogenesis of retinitis and retinal vasculopathy in AIDS patients. 132 96

A novel membrane-bound serine esterase in cultured human T4+ lymphocytes, recently purified and named tryptase TL2, binds specifically to the external envelope protein gp 120 of HIV-1, interacting with its V3 domain. This binding was selectively blocked by inhibitors of tryptase TL2 with a GPCR sequence in their reactive site, synthetic peptides corresponding with the sequences of the V3 domains of various HIV-1 strains with the GPGR sequence, and antibody against tryptase TL2, or neutralizing antibody against the V3 domain of HTLV-IIIB. These findings suggest that tryptase TL2 is a binding protein of the V3 domain of HIV-1 envelope glycoprotein.
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PMID:Tryptase TL2 in the membrane of human T4+ lymphocytes is a novel binding protein of the V3 domain of HIV-1 envelope glycoprotein gp 120. 167 98

HIV-1 was found sensitive to inactivation by low concentrations of trypsin. The use of trypsin was valuable for assessing non-specific binding of HIV virions to CD4+ cells. This effect was also helpful for eliminating input virus in experiments studying HIV infection of cells in vitro.
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PMID:Inactivation of HIV-1 by trypsin and its use in demonstrating specific virus infection of cells. 168 37

A novel membrane-bound serine esterase, named tryptase TL2, which is immunologically reactive with the antibody inhibiting induction of syncytia by human immunodeficiency virus-1 (HIV-1) (HATTORI, T., KOITO, A., TAKATSUKI, K., KIDO, H., and KATUNUMA, N., 1989, FEBS Lett., 248, 48-52), has been purified from a human T4+ lymphocyte clone. The enzyme has a molecular mass of 198 +/- 15 kDa, and is composed of two subunits of 32 kDa and four subunits of 28 kDa. The enzyme was strongly inhibited by the envelope glycoprotein gp120 of HIV-1, by synthetic peptides of V3 domains of gp120 s with the sequence GPGR in their center, which correspond to the principal neutralizing epitopes of the gp120s of various HIV-1 strains, by Kunitz-type inhibitors with the sequence GPCR in their active site, such as trypstatin, H130, and [Arg15, Glu52] aprotinin and by the microbial inhibitors leupeptin and antipain. This enzyme was specifically bound to the inhibitor V3 domain of gp120 of HIV-1, and this binding was blocked by the inhibitors of tryptase TL2, with a central motif GPCR or GPGR sequence in their center, but not by leupeptin and antipain without the motif. These findings suggest that tryptase TL2 is important in target site recognition and binding of HIV-1 in co-operation with CD4 receptor in the initial process of HIV-1 infection.
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PMID:A novel membrane-bound serine esterase in human T4(+)-lymphocytes is a binding protein of envelope glycoprotein gp120 of HIV-1. 168 71

Langerhans cells (LC) are epidermal dendritic cells which express several surface antigens, among them the CD4 antigens. Recent data demonstrated that LC constitute target and storage cells for HIV. To better understand the interactions between HIV and LC, we investigated, in the present work, the fate of HIV envelope glycoproteins (gp120 and gp160) incubated with healthy human trypsinized LC in suspensions. After trypsin treatment, only the epitope for OKT4 appeared to be resistant on LC. In the absence of antigenic sites identified by OKT4A, Leu3a or BL4 (epitopes implicated in HIV binding), LC bound and internalized recombinant HIV gp120 or gp160. This finding supports the hypothesis that there exists at the surface of LC a second molecule which may act as an HIV receptor.
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PMID:In vitro binding and internalization of HIV envelope glycoproteins by human epidermal Langerhans cells does not require the CD4-gp120-binding site. 169 20

Various combinations of inhibitors of HIV reverse transcriptase were tested for inhibition of HIV replication in order to reveal any potential synergism or antagonism. PFA, a pyrophosphate analogue, gave synergistic inhibition of HIV replication in combination with both of the thymidine analogues AZT and FLT. The combination of PFA and AZT-TP gave only additive or weakly synergistic inhibition in a reverse transcriptase enzyme assay. The combination of AZT and FLT also gave synergistic inhibition of HIV replication, whilst the combination of AZT-TP and FLT-TP gave only additive or weakly synergistic inhibition of reverse transcriptase. Thus, the synergy does not arise from effects on reverse transcriptase alone but must be owing to other, cellular factors, such as effects on nucleoside metabolism or metabolism of the analogues. The results are consistent with the hypothesis that AZT may have an alternative mechanism of inhibition other than inhibition of reverse transcriptase. The diminished cytotoxicity observed in addition to the synergistic inhibition makes these combinations attractive from the point of view of combination chemotherapy. The inhibition of HIV replication by peptides from various parts of the V3 region of gp120 whose sequences were homologous with the tryptase inhibitor trypstatin was tested. Inhibitory activity was displayed by two peptides containing cysteine in their sequence. Antibodies to two peptides containing the two conserved cysteine residues from opposite sides of the neutralizing loop of gp120 were previously associated with protection from vertical transmission of HIV. The V3 region thus seems to be important for the function of gp120 and the transmission of HIV.
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PMID:Synergistic combinations and peptides in the inhibition of human immunodeficiency virus. 171 18

The CD4 molecule is known to be the preferential receptor for the HIV-1 envelope glycoprotein. Epidermal Langerhans cells are dendritic cells which express several surface antigens, among them CD4 antigens. To clarify the exact role of CD4 molecules in Langerhans cell infection induced by HIV-1, we investigated the possible involvement of the interactions between HIV-1 gp 120 or HIV-1 gp 160s (soluble gp 160) and Langerhans cell surface. We also assessed the expression of CD4 molecules on Langerhans cell membranes dissociated by means of trypsin from their neighbouring keratinocytes. The cellular phenotype was monitored using flow cytometry and quantitative immunoelectron microscopy. We reported that human Langerhans cells can bind the viral envelope proteins (gp 120 or gp 160s), and that this binding does not depend on CD4 protein expression. This binding is not blocked by anti-CD4 monoclonal antibodies. We show that a proportion of gp 120/gp 160s-receptor complexes enters Langerhans cells by a process identified as a receptor-mediated endocytosis. The amount of surface bound gp 120/gp 160s is not consistent with the amount of CD4 antigens present on Langerhans cell membranes. Gp 120/gp 160s binding sites on Langerhans cell suspensions appeared to be trypsin resistant, while CD4 antigens (at least the epitopes known to bind the HIV-1) are trypsin sensitive. A burst of gp 120 receptor expression was detected on 1-day cultured Langerhans cells while CD4 antigens disappeared. These findings lead to the most logical conclusion that binding of gp 120/gp 160s is due to the presence of a Langerhans cell surface molecule different from CD4 antigens.
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PMID:Interaction of human epidermal Langerhans cells with HIV-1 viral envelope proteins (gp 120 and gp 160s) involves a receptor-mediated endocytosis independent of the CD4 T4A epitope. 172 50

The remarkable ability of HIV to insinuate itself into the working of the immune system is the key of its success as an infectious agent. Given that the cytokine network regulates the immune responses, it is not surprising that cytokines can modulate HIV infection. GM-CSF, IL6 and TNF-alpha enhance HIV, but TGF-beta and HIF inhibits the virus. However, the anti-HIV activity of TGF-beta is restricted to myeloid cells, while HIF inhibits HIV in myeloid cells and in T-lymphocytes. HIF is produced by CEM cells after induction by an extract from pine cones. It is not an interferon and is likely a novel cytokine. It is pepsin-sensitive but trypsin-resistant and has an apparent molecular weight of 7-12 KDa. Apart from having anti-HIV activity, crude preparations of HIF also inhibit HTLV-1 virus but not HSV virus replication.
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PMID:Cytokine regulation of the human immunodeficiency virus (HIV). 172 85

Serum concentrations of trypsin and elastase I were determined in 109 HIV Ab-positive patients (52 asymptomatic HIV-infected patients, 25 with lymphadenopathy syndrome, and 32 with acquired immunodeficiency syndrome) to assess the prevalence of possible pancreatic damage in these patients. Serum trypsin was abnormally elevated in 46 of the 109 patients (42.2%): 19 of the 52 asymptomatic HIV-infected patients (36.6%), 9 of the 25 with lymphadenopathy syndrome (36%), and 18 of the 32 with acquired immunodeficiency syndrome (56.3%). Serum elastase 1 was elevated in 14 of the 109 HIV Ab-positive patients (12.8%): 3 of the 52 asymptomatic HIV-infected patients (5.8%), 3 of the 25 with lymphadenopathy syndrome (12%), and 8 of the 32 with acquired immunodeficiency syndrome (25%). None of the patients with abnormally high serum pancreatic enzyme concentrations had clinically evident pancreatic disease. There was no statistically significant difference in serum levels of trypsin and elastase I between drug addicts and nonaddicts, between alcoholics and nonalcoholics, or between those with cytomegalovirus infection and those without. A significant inverse relationship was found between serum enzyme concentrations and the number of CD4+ lymphocytes. The results of this study show that high levels of serum trypsin and elastase are present in an elevated percentage of patients with acquired immunodeficiency syndrome, suggesting that the pancreas is frequently damaged in this disease. The finding of abnormally high serum enzyme concentrations not only in patients with AIDS, but also in asymptomatic carriers and in patients with lymphadenopathy syndrome suggests an association between HIV infection and the development of pancreatic lesions.
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PMID:Serum pancreatic enzymes in HIV-seropositive patients. 173 48


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