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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have described the isolation of chemically induced CEM subclones that express CD4 receptors and bind soluble gp120, yet show a markedly reduced susceptibility to infection with HIV-1. Two subclones were found to have an abnormal response to the protein kinase C (PKC) activator PMA. PMA treatment induced CD3 and CD25 (IL-2R) receptors on the parental line and on other ethyl-methanesulfonate-derived subclones, but not on these two mutants. Direct assays of PKC activity were conducted. Total cellular PKC enzymatic activity was found to be normal in these subclones. PMA-induced CD4 down-modulation occurred normally. In addition, activation of c-raf kinase was normal. Since HIV-1 long terminal repeat contains two functional nuclear factor kB (NF-kB) regulatory elements, we studied the ability of PMA to induce NF-kB binding activity by different assays. Chloramphenicol acetyl transferase (CAT) assays using the HIV-1 (-139)long terminal repeat-CAT construct showed no PMA induction of CAT activity in these subclones (unlike the parental line and other subclones). Okadaic acid, an inhibitor of phosphatases 1 and 2A, did not overcome the defect in these subclones. Gel retardation assays, using a 32P-probe containing the HIV-1 NF-kB probe and nuclear extracts from PMA-treated cells, showed significantly reduced induction of nuclear NF-kB binding proteins in these two subclones compared with wild type CEM and a control subclone. Deoxycholate treatment of cytoplasmic extracts from these subclones released much reduced NF-kB binding proteins from their cytoplasmic pools. Thus, reduced levels of PKC-induced nuclear NF-kB activity in two T cell subclones did not affect their normal cell growth, but correlated with a pronounced reduction in their susceptibility to HIV-1 infection.
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PMID:Reduced susceptibility to HIV-1 infection of ethyl-methanesulfonate-treated CEM subclones correlates with a blockade in their protein kinase C signaling pathway. 135 Oct 90

While expression of complement receptor 2 (CR2) (CD21) on some CD4+ cell lines renders them more susceptible to infection by complement-treated human immunodeficiency virus (HIV), coexpression of CR2 and CD4 on peripheral blood lymphocytes has not, until recently, been observed. Several recent studies, however, have found that human T lymphocytes express low levels of CR2. Additionally, complement treatment of HIV before addition to these cells has been reported to increase virus expression in peripheral blood lymphocyte cultures. These findings suggest that complement-mediated enhancement of infection of human T cells could occur in vivo and have prompted us to examine both the phenotypic properties of CD4+CR2+ T cells in healthy persons and the expression of CR2 on CD4+ lymphocytes during HIV infection. As was previously reported, we observed CR2 on a proportion (10-50%) of both CD8+ and CD4+ T cells. Approximately half of CD4+CR2+ cells expressed the memory cell markers CD45RO and CD29, 80% expressed the naive marker CD45RA, while 22% expressed CD25. These values were not substantially different from total CD4+ cells. Stimulation of lymphocytes with phytohaemagglutinin (PHA), OKT3 or calcium ionophore but not with phorbol myristate acetate (PMA) or interleukin-2 (IL-2) decreased expression of CR2 on CD4 cells by half over a 3-day culture period. The per cent of CD4+ cells expressing CR2 was significantly decreased in patients with asymptomatic and symptomatic HIV infection compared to uninfected control donors (P = 0.0001). In contrast, the decrease in CR2 expression was not observed with CD8+ lymphocytes from HIV-infected persons. These results confirm that CR2 is expressed on human T lymphocytes and suggest that a subset of CD4+ lymphocytes is selectively affected in HIV-infected individuals.
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PMID:Phenotypic analysis of complement receptor 2+ T lymphocytes: reduced expression on CD4+ cells in HIV-infected persons. 137 93

HIV-related non-hodgkin lymphomas currently occur in 5 to 8% of AIDS patients. AIDS-related lymphomas are high-grade tumors with the morphologic characteristics of either small noncleaved cell lymphomas of the Burkitt type or large cell centroblastic and immunoblastic lymphomas. Mixed features may be found, making classification difficult. Useful methods for characterizing AIDS-related non-hodgkin's lymphomas include immunophenotypic studies using B-cell differentiation and activation antigens (HLA-DR, CD10, CD19, CD20, CD21, CD22, CD23, CD38), evaluation of expression of surface immunoglobulins (IgS), activation and proliferation (CD25, CD30, CD71, Ki67), and identification of T-cell markers (CD1, CD2, CD3, CD4, CD5, CD7, CD8). Cases studied were of the B-cell type. Comparison with morphologic features revealed that Burkitt's lymphomas were monoclonal and expressed B-cell markers (CD10, CD19, CD20, CD22, CD38) and surface immunoglobulins, especially IgM kappa. This immunophenotype is similar to that of large cell or centroblastic non-hodgkin's lymphomas, suggesting that Burkitt lymphomas originate from centrofollicular cells. Immunoblastic non-hodgkin's lymphomas were monotypic or polytypic and expressed CD10 and CD38 antigens but not the other B-cell antigens Furthermore, a very large number of cells stained positively with the Ki67 antibody demonstrating that most lymphoma cells were undergoing cycling.
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PMID:[Non-Hodgkin's lymphoma and AIDS: histopathologic features]. 144 58

The CD25 (IL-2-R alpha) cell surface glycoprotein expressed transiently during T-cell activation is implicated in the high affinity IL-2 receptor. This paper shows that cell-free supernatants from chronically HIV-infected promonocytic cells spontaneously produce a soluble factor which inhibits CD25 expression on PHA-activated human PBMC. We purified the CD25 expression inhibitory activity by a factor 12,350, using XM50 ultrafiltration, Superose 12 molecular sieving chromatography and MonoQ anion-exchange chromatography. Then we associated this activity to one single spot (M(r) 29,000, pI 6.8) on an O'Farrell two-dimensional gel. Our data demonstrate that this protein (M(r) 29,000, pI 6.8) is released from HIV-infected promonocytic cells and suggest that this factor is a new monokine regulating the T-cell activation process.
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PMID:Purification and identification of a CD25 expression inhibitory protein from cell-free supernatants of chronically HIV-infected promonocytic cells. 151 55

The intestinal mucosa is an important portal of entry of HIV, and HIV-infected mononuclear cells are found in the intestinal lamina propria of 30 to 50% of HIV-infected patients even at early stages of the disease. HIV infection of epithelial cells has not consistently been detected and is still controversial. Intestinal T cells are phenotypically and functionally distinct from circulating T cells, especially in their state of activation and differentiation, which both affect the replication and cytopathicity of HIV. An increase in CD8+ cells and variable decreases in CD4+ cells have been found in the intestinal lamina propria by immunohistologic studies, resulting in a decreased CD4 to CD8 ratio; in addition, CD25 expression is reduced. Changes in intraepithelial lymphocytes are unclear. B-cell differentiation seems to be disturbed because IgA plasma cells and IgA2 secretion are reduced. Depletion or functional impairment of activated mucosal lamina propria lymphocytes by HIV infection could explain the breakdown of the mucosal immune barrier leading to opportunistic diseases; in addition, due to the interrelationship between mucosal immune system and epithelium, these changes might be responsible for the partial bowel atrophy and maturational defects in enterocytes of HIV-infected patients.
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PMID:Enteric immunologic abnormalities in human immunodeficiency virus infection. 163 19

Non-Hodgkin's lymphomas (NHL) are part of the spectrum of disease associated with HIV infection. However, there are only occasional reports of NHL of T-cell origin in HIV-infected patients. A previously asymptomatic HIV-infected man, who was seronegative for human T-lymphotropic virus type I antibodies, developed a high-grade peripheral T-cell lymphoma of anaplastic large-cell type which was Ki-1 + (CD30 +), HLA-DR+, epithelial membrane antigen +, CD25 +, CD71 +, CD2 + and CD5 +. Pan-B markers CD19 and CD22 and histiocytic marker CD68 were negative. At diagnosis the patient had 0.3 x 10(9)/l T-helper lymphocytes. The response to chemotherapy was dramatic and the patient is alive and disease-free 18 months after treatment. A review of previously described peripheral T-cell lymphomas in HIV-positive individuals is performed, and we conclude that the spectrum of neoplasms in such cases is probably broader than originally thought.
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PMID:Ki-1+ anaplastic large-cell lymphoma of T-cell origin in an HIV-infected patient. 165 81

Lymphocyte activation induces production of soluble IL-2 receptor (sIL-2R) which is a large portion of the CD25 membrane molecule and which is detectable in serum. Serum sIL-2R is reported here to increase as a direct effect of the HIV infection and not to be due to secondary opportunistic infections. sIL-2R increased promptly after HIV seroconversion in 83% of 50 initially seronegative homosexual men. The sIL-2R serum levels stabilized in the third year after seroconversion and were then predictive of later CD4 T cell levels and development of AIDS. In two studies of 59 and 395 seropositive men, beta-2 microglobulin (B2M) and neopterin levels in serum correlated closely with each other but not with sIL-2R levels. Thus, increased production of sIL-2R may reflect pathological processes distinct from those determining B2M and neopterin increases. Membrane CD25 expression on peripheral blood lymphocytes, unexpectedly, was found to be decreased in HIV infection. This contrasted with the increased sIL-2R in serum. Investigations with sensitive flow cytometry technics showed that CD25 was expressed at reduced levels and averaged only 12% of lymphocytes from HIV-infected individuals in contrast to 25% in noninfected individuals. All major lymphoid populations showed reductions in CD25 positive cells. This reduction in lymphoid membrane CD25, however, was not inversely correlated with the increased serum levels of sIL-2R or with other parameters of immune deficiency or activation. Thus, surface CD25 loss and serum sIL-2R increase are separate and independent consequences of HIV infection.
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PMID:Serum increases and lymphoid cell surface losses of IL-2 receptor CD25 in HIV infection: distinctive parameters of HIV-induced change. 168 May 89

The immunomodulatory drug isoprinosine has been found to delay the occurrence of opportunistic infections in HIV-infected individuals. To elucidate the mechanism of action, eight HIV-positive, healthy patients were treated with isoprinosine, 3 g/day for 28 days; six patients received no treatment but were examined in parallel, and two patients were withdrawn. All patients had blood collected just before the start as well as on days 14 and 28 of isoprinosine treatment. Isoprinosine significantly enhanced the lymphoproliferative response after stimulation with phytohaemagglutinin (PHA) and purified derivative of tuberculin (PPD), while isoprinosine had no effect on the following immune parameters: the expression of surface markers on blood mononuclear cells including CD2, CD3, CD4, CD8, CD14, CD19, CD20, CD25, leu-8, and HLA-DR. Furthermore isoprinosine did not influence the ability of interleukin 2 (IL-2) to stimulate the proliferation of lymphocytes or the natural killer (NK) cell activity either unstimulated or stimulated in vitro with alpha interferon (IFN-alpha), IL-2, or indomethacin. Neither did isoprinosine affect the in vitro production of (IL-1) alpha or beta, IL-2, IL-6, or tumour necrosis factor (TNF).
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PMID:Effects of isoprinosine treatment of HIV-positive patients on blood mononuclear cell subsets, NK- and T-cell function, tumour necrosis factor, and interleukins 1, 2, and 6. 170 99

Using a high-sensitivity immunofluorescence procedure, a proportion of blood lymphocytes can be shown to express the p55 chain of the IL-2 receptor (CD25, TAC) without in vitro stimulation. In this study, we measured the proportion of peripheral blood lymphocytes expressing CD25 in patients with a diagnosis of HIV infection and compared the results with cells from controls. The mean value for HIV-positive samples was 15%, while controls gave a mean value of 31%. The difference between the groups was highly significant (P less than 0.001, Mann-Whitney U test). When expression of CD25 was examined separately in CD4-positive and CD8-positive T cells and in B cells, there was a wider spread of values in the HIV group compared with controls, but no systematic difference. In the patient group studied (110 samples from 53 patients) there was a weak correlation between CD25 and CD4 expression (correlation coefficient r = 0.21, P less than 0.02), but there were patients with low CD25 and high CD4 as well as patients with high CD25 and low CD4, suggesting that CD25 can vary independently of changes in CD4 lymphocytes. Although the majority of very low values of CD25 (less than 10%) were found in patients with stage IV disease, such low values were also common in Stage II disease.
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PMID:Patients with HIV infection have a reduced proportion of lymphocytes expressing the IL2 receptor p55 chain (TAC, CD25). 170 15

Although alterations in T lymphocyte subset distribution and function in the peripheral blood of HIV-infected humans are well defined, the extent to which these reflect changes in other lymphoid compartments is unclear. We have characterized the coincident changes in PBL and lymph nodes (LN)1 after simian immunodeficiency virus of macaques (SIVmac) infection of rhesus monkeys. Whereas no consistent change in CD8+ PBL was noted during the first 60 d after infection, CD8+ lymphocytes increased significantly in number in LN. These CD8+ LN lymphocytes exhibited an increased expression of MHC class II and a decreased expression of leukocyte adhesion molecule-1, suggesting that they were activated, but interestingly did not express CD25 (IL-2 receptor). Moreover, there was no evidence that these CD8+ LN cells were proliferating, suggesting that they had migrated to the LN. These changes in the LN CD8+ lymphocyte population preceded any detectable change in the light microscopic appearance of the LN. When SIVmac-specific effector T cell responses were assessed, the magnitude of virus-specific effector activity was nearly identical in the PBL and LN of each monkey studied. However, the presence of SIVmac-specific effector cells in the LN did not correlate with the presence of CD8+, MHC class II+ cells. These findings suggest that this numerically important CD8+ lymphocyte subpopulation may serve a regulatory function.
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PMID:An activated CD8+ lymphocyte appears in lymph nodes of rhesus monkeys early after infection with simian immunodeficiency virus. 171 8


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