Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CD3+CD8+CD11+ cells were present in the peripheral blood of patients infected with asymptomatic human immunodeficiency virus (HIV) in higher percentage (10-20%) than in normal individuals (3-5%) in this study. These cells, through the release of soluble factors, significantly suppressed the effector phase of anti-HIV cytotoxic activities, both human leukocyte antigen (HLA)-class I or class II restricted, and nonrestricted. The effectors were CD8+CD11-, CD4+ T cells, and CD16+ cells for HLA-class I, class II restricted, and nonrestricted cytotoxicities, respectively. The soluble factors also inhibited natural killer cell activity. Thus, this effect was neither HLA-restricted nor antigen-specific. These CD3+CD8+CD11+ cells may be an important immunopathogenic factor in HIV disease.
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PMID:CD8+ CD11+ suppressor cells in HIV-infected asymptomatic patients: effect on HIV-specific cytotoxicity. 135 30

A high proportion of Staphylococcus aureus strains of human origin produce one or more exotoxins. In vivo, these toxins may give rise to a variety of clinical syndromes. In vitro, staphylococcal exotoxins have been shown to bind both to human leukocyte antigen (HLA) class II molecules on antigen-presenting cells and to the T-cell receptors on large fractions of T cells. The result of this interaction may be proliferation of the T cells, T-cell anergy, or apoptosis, depending on several factors, including the state of the responding cells and the presence of accessory molecules. Using naturally infected peripheral blood mononuclear cells depleted of CD8+ T cells, we have shown that staphylococcal exotoxins are powerful inducers of human immunodeficiency virus type 1 expression and that they induce expression at low concentrations and with greater efficiency than other T-cell mitogens. Human immunodeficiency virus type 1 was produced entirely by CD4+ T cells in this model; monocytes were expendable both as a source of virus and as a source of HLA class II molecules as long as other cells expressing HLA class II molecules were present. The results suggest that infection by S. aureus may be a cofactor in the immunopathogenesis of AIDS.
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PMID:Staphylococcal exotoxin superantigens induce human immunodeficiency virus type 1 expression in naturally infected CD4+ T cells. 135 59

In 8 of 12 experimentally infected macaques, the Nef SIVmac 251 protein was recognized by cytolytic T lymphocytes (CTL) and appeared strongly immunogenic. Here, we report experiments which have been performed by using synthetic peptides to precisely determine the epitopes recognized by macaque CTL. Three epitopes of the Nef protein have been defined as CTL targets in three macaques. The epitopic peptides are located in the central region of the protein, and all of them show high homology with peptides of the human immunodeficiency virus type 1 Nef protein recognized by human CTL in association with several human leukocyte antigen molecules. These results suggest that (i) the Nef protein is a good candidate for vaccination not only because of its early expression but also because of its high immunogenicity for CTL, (ii) long peptides covering the central region of this protein could be used as vaccines and could cross the major histocompatibility complex barrier in a large variety of individuals, and (iii) the rhesus macaque is a good animal model in which to test for protection by CTL.
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PMID:Three epitopic peptides of the simian immunodeficiency virus Nef protein recognized by macaque cytolytic T lymphocytes. 137 May 57

A human leukocyte antigen A24-restricted CD8+ cytotoxic T-cell clone specific for gp41 of human immunodeficiency virus type 1 was isolated from an infected individual. The epitope was localized to amino acids 584 to 591 (YLKDQQLL, NL43 env sequence) of gp41 by using a panel of recombinant vaccinia viruses that contain truncated env genes and synthetic peptides. The clone killed autologous B-lymphoblastoid cell lines pulsed with a synthetic peptide reflecting the sequence of the IIIB and MN strains. This clone, however, failed to kill target cells pulsed with the peptides that have a mutation from Lys to Arg or Gln at amino acid 585 which is present in some prototype human immunodeficiency virus type 1 strains, e.g., ADA, JFL, SC, ALA1, BAL1, SF2, VRF, SF33, and WMJ2. This finding that a mutation at amino acid 585 on gp41 results in nonrecognition by human leukocyte antigen A24-restricted CD8+ cytotoxic T lymphocytes suggests that antigenic variation at T-cell epitopes contributes to the failure of immune control of human immunodeficiency virus type 1 infections.
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PMID:Mutation of human immunodeficiency virus type 1 at amino acid 585 on gp41 results in loss of killing by CD8+ A24-restricted cytotoxic T lymphocytes. 137 4

The lymphocyte activation gene 3 (LAG-3), expressed in human activated T and natural killer (NK) cells, is closely related to CD4 at the gene and protein levels. We report here the initial characterization of the LAG-3-encoded protein. We have generated two monoclonal antibodies after immunization of mice with a 30-amino acid peptide that corresponds to an exposed extra loop region present in the LAG-3 immunoglobulin-like first domain. The reactivity of these reagents is directed against LAG-3 since they recognize both membrane-expressed and soluble recombinant LAG-3 molecules produced in a baculovirus expression system. The two antibodies are likely to react with the same or closely related epitope (termed LAG-3.1) exposed on the LAG-3 first domain extra loop, as assessed in competition experiments on LAG-3-expressing activated lymphocytes. Cellular distribution analysis indicated that the LAG-3.1 epitope is expressed on activated T (both CD4+ and CD8+ subsets) and NK cells, and not on activated B cells or monocytes. In immunoprecipitation experiments performed on activated T and NK cell lysates, a 70-kD protein was detected after SDS-PAGE analysis. 45-kD protein species were also immunoprecipitated. Both the 70- and 45-kD proteins were shown to be N-glycosylated. In Western blot analysis, only the former molecule was recognized by the anti-LAG-3 antibodies, demonstrating that it is LAG-3 encoded. These anti-LAG-3 antibodies were used to investigate whether the LAG-3 protein interacts with the CD4 ligands. By using a high-level expression cellular system based on COS-7 cell transfection with recombinant CDM8 vectors and a quantitative cellular adhesion assay, we demonstrate that rosette formation between LAG-3-transfected COS-7 cells and human leukocyte antigen (HLA) class II-bearing B lymphocytes is specifically dependent on LAG-3/HLA class II interaction. In contrast to CD4, LAG-3 does not bind the human immunodeficiency virus gp120. This initial characterization will guide further studies on the functions of this molecule, which may play an important role in immune responses mediated by T and NK lymphocytes.
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PMID:Characterization of the lymphocyte activation gene 3-encoded protein. A new ligand for human leukocyte antigen class II antigens. 138 59

Blood sampling on filter paper has many advantages for the detection of perinatal human immunodeficiency virus (HIV) infection by the polymerase chain reaction (PCR). However, if the method is to be widely used, an assessment of its performance under field conditions is required. To simulate conditions in the field, 50-microliters aliquots of whole blood containing low levels of HIV proviral DNA (4 to 1,024 copies per 100,000 nucleated cells) were spotted onto filter paper; dried; and subjected to heat, humidity, and prolonged storage at room temperature. After exposure, the DNA was recovered and amplified with primers to human leukocyte antigen DQ alpha- and HIV-specific sequences. Treatment at 37 degrees C and 60% humidity for 7 days, storage for 12 weeks at 22 degrees C, and freeze-thawing twice had no adverse effect on PCR reactivity when compared with the results obtained with reference spots stored at -20 degrees C. The lower limits of HIV detection in all tests ranged from 4 to 16 HIV copies per 100,000 cells. Fixation in 70% ethanol improved the amplification of low levels of HIV DNA and reduced biohazard risks. These findings suggest that dried blood spots will provide a powerful new resource for testing for HIV by PCR, especially in remote areas where refrigeration and immediate sample processing are unavailable.
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PMID:Stability of dried blood spot specimens for detection of human immunodeficiency virus DNA by polymerase chain reaction. 145 82

A 16 year old boy underwent allogeneic bone marrow transplantation (BMT) from an human leukocyte antigen (HLA)-identical sibling for severe aplastic anaemia. He was symptomatic for 7 years before transplantation and had received multiple red blood cell and platelet transfusions. Conditioning for BMT consisted of cyclophosphamide, antilymphocyte globulin and total lymphoid irradiation. Engraftment was rapid, there was no evidence of rejection despite the history of multiple blood product transfusions and he did not develop acute or chronic graft versus host disease. He was well for the first 8 months after transplantation but then developed fevers, interstitial pneumonia, herpes simplex infections and cytomegalovirus enteritis. Serological studies revealed antibodies to human immunodeficiency virus (HIV) and he was considered to have acquired immune deficiency syndrome (AIDS). Retrospective analysis of the serum samples showed that he was seronegative for HIV until approximately 10 months before transplantation when his serum became HIV positive. Lymphocyte function studies done after transplantation suggested immunologic recovery at 3 months post-transplant with a brisk though subnormal response to phytohaemagglutinin stimulation. T cell subset analysis performed subsequently showed complete absence of CD4 positive cells indicating immune incompetence which was associated with clinical features of AIDS. Bone marrow transplantation had failed to produce sustained immunologic reconstitution and prevent the progression of HIV to which he ultimately succumbed.
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PMID:Failure of allogeneic bone marrow transplantation to benefit HIV infection. 149 64

A unique epitope on the gag protein of human immunodeficiency virus type 1 (HIV-1), located at amino acid 145 to 150, has been mapped by using a CD8+ cytotoxic T-lymphocyte (CTL) clone. This epitope is highly conserved among 18 HIV-1 strains. The HIV-1 gag-specific human leukocyte antigen (HLA) class I-restricted CD8+ CTL clone was generated from fresh peripheral blood mononuclear cells of an HIV-seropositive donor by stimulation with gamma-irradiated allogeneic peripheral blood mononuclear cells in the presence of an anti-CD3 monoclonal antibody and recombinant interleukin-2. This gag-specific CTL clone killed autologous target cells infected with a recombinant vaccinia virus containing the gag gene of HIV-1 and target cells pulsed with an authentic p24gag construct expressed in Escherichia coli. Fine specificity was determined by using a panel of overlapping 30-amino-acid-long synthetic peptides and subsequently using smaller peptides to precisely map the CTL domain on p24. The epitope is on a highly conserved region, and it overlaps with a major B-cell epitope of gag. This CD8+ T-cell epitope is restricted by HLA-Cw3, which has not been previously identified as a restricting element for human CTL responses.
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PMID:An HLA-C-restricted CD8+ cytotoxic T-lymphocyte clone recognizes a highly conserved epitope on human immunodeficiency virus type 1 gag. 171 57

T cell immunity may be critical to development of a vaccine for human immunodeficiency virus (HIV-1). T helper epitopes were identified in three predominantly conserved regions in the HIV-1 reverse transcriptase by using reverse transcriptase-immunized mice of five major histocompatibility complex haplotypes. One peptide (residues 38-52) that stimulated H-2k T cells also contained an epitope recognized by cytotoxic T cells from the same mice and from HIV-infected patients. Such concordance between helper and cytotoxic T lymphocyte epitopes, observed in four cases, may be important in vaccine development. Peptide 36-52 was recognized by interleukin-2-producing peripheral blood T cells from 9 of 17 HIV-seropositive humans studied, of multiple human leukocyte antigen-DR and -DQ types. The broad recognition of this peptide by both helper and cytotoxic T cells substantiates its potential importance in a vaccine.
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PMID:Human immunodeficiency virus reverse transcriptase T helper epitopes identified in mice and humans: correlation with a cytotoxic T cell epitope. 172 Jan 51

In the present paper we analyze the role of major histocompatibility gene products, the human leukocyte antigens, in the pathophysiology of the acquired immunodeficiency syndrome. No association has been found between human leukocyte antigen (HLA) frequencies and human immunodeficiency virus type 1 (HIV 1) infection, whereas significant associations have been reported in some populations between some HLA haplotypes and the appearance of either opportunistic infections or secondary cancers. With regard to the human leukocyte class I antigens, their role as restriction elements in presenting HIV 1 to virus-specific cytotoxic T lymphocytes seems to be established. An increase in the serum levels of their soluble forms that correlate with disease stage has also been demonstrated. These circulating molecules could interfere with the immune response to HIV 1 and could contribute to the development of the immunodeficiency. Antigenic similarities have been detected between human leukocyte class II antigens and HIV 1 envelope proteins. These homologies could explain both the presence in some HIV-positive sera of anti-HLA class II antibodies that mediate the lysis of CD4(+)-HLA class II+ T cells and the false-positive reaction of some HIV-negative sera, which contain anti-HLA class II antibodies, in tests for HIV 1 antibodies. Reduced levels of some complement factors (the human leukocyte class III antigens) have been detected in HIV-infected subjects. These defects could play a role in the progression of the disease and affect both the clearance of HIV 1 and complement-mediated antibody responses. The data reported in this review suggest that HLA antigens may be involved in several steps of the immune deficiency of HIV-infected subjects and thus contribute to the pathophysiology of acquired immunodeficiency syndrome.
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PMID:Major histocompatibility gene products and human immunodeficiency virus infection. 199 62


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