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

It has been well established that psoriasis, psoriatic arthritis, and Reiter's syndrome can occur in patients with HIV infection. These arthocutaneous diseases tend to occur in temporal proximity to the development of AIDS and ARC, and their clinical manifestations are unusually severe. The appearance or exacerbation of psoriasis, arthritis, or Reiter's syndrome in a high-risk person should alert the clinician to possible underlying HIV infection. Treatment should be dictated by the severity of the skin and musculoskeletal disease as well as by the status of the immune system. Zidovudine appears to be effective in many diseases, especially psoriasis, and nonsteroidal antiinflammatory drugs are the mainstay for arthritis. Immunosuppressive agents such as methotrexate and azathioprine are contraindicated because they exacerbate immunodeficiency and promote infections. Epidemiologic studies suggest that the prevalence of these diseases, especially Reiter's syndrome, may be higher in HIV-positive populations than previously thought, especially in those patients with AIDS and ARC. Immunogenetic factors like HLA-B27 are important in the predisposition to Reiter's syndrome associated with HIV infection; however, it is not clear what role they play in HIV-associated psoriasis. Mechanisms underlying these observations remain unclear, although potential insights into the pathogeneses of psoriasis and Reiter's syndrome may be gained through future studies. Already it seems likely that CD4-positive helper T-cells, the target of HIV, are not necessary for the expression of psoriasis or Reiter's syndrome, and because of HLA class I associations, a role for CD8 positive cytotoxic T lymphocytes can be suspected. Infections, promoted by the profound immunodeficiency of AIDS, seem to be the most plausible explanations for the cutaneous and articular complications of HIV infection.
 ...
PMID:Psoriasis and psoriatic arthritis associated with human immunodeficiency virus infection. 204 89

We have tested the binding of HLA class I proteins to peptides using a solid-phase binding assay. We tested 102 peptides, mostly derived from the HIV gag and HIV pol sequences. Most peptides did not bind to any class I protein tested. The pattern of binding among the three class I proteins tested, HLA-A2, -B27, and -B8, was approximately 85% concordant. Further, all five of the known HIV-1 gag T cell epitopes detected by human CTL bound at least one class I protein. Binding of class I to the peptides could be detected either by directly iodinated class I proteins, or indirectly using monoclonal antibodies specific for class I. The binding to the plates could be blocked with MA2.1, which binds in the alpha 1 region of A2, but not by W6/32, which binds elsewhere. The data presented here show that binding of class I to peptides is specific, but that many peptides bind to more than a single class I protein.
 ...
PMID:Evidence of widespread binding of HLA class I molecules to peptides. 220 49

The physical association of 40 antigenic peptides and purified HLA class I and class II molecules was monitored using a direct peptide binding assay (PBA) in solid phase and an inhibition peptide binding assay (IPBA) in which the competing peptide was present in a soluble phase. We also examined the ability of different peptides to inhibit the lytic activity of human antiviral cytolytic T cells towards cells incubated with the corresponding target peptide. Our results showed that: (a) Binding of a given human T cell-recognized peptide to several HLA class I and class II molecules occurred frequently. Nevertheless, preferential binding of peptides to their respective restriction molecules was also observed. (b) Binding of HLA molecules to peptides recognized by murine T cells occurred less frequently. (c) 11 of 24 (46%) randomly selected HIV-1 peptides contained agretopic residues allowing their binding to HLA molecules. (d) The kinetics of HLA/peptide association depended on the peptide tested and were faster than or similar to those reported for Ia molecules. Dissociation of these complexes was very low. (e) Peptide/HLA molecule binding was dependent on length, number of positive charges, and presence of hydrophobic residue in the peptide. (f) A correlation was demonstrated between a peptide inhibitory effect in the IPBA and its blocking effect in the cytolytic test. Our data indicated that the restriction phenomenon observed in T cell responses was not strictly related to either an elective HLA/peptide association, or a high binding capacity of a peptide to HLA molecules. These data also showed that the PBA and IPBA are appropriate for the detection of agretopic residues within HIV-1 proteins.
 ...
PMID:Analysis of physical interactions between peptides and HLA molecules and application to the detection of human immunodeficiency virus 1 antigenic peptides. 238 36

By means of indirect immunofluorescence analysis we investigated the effect of HIV-1 infection on HLA class I surface antigens. We report here that in CD4+ HeLa cells, in H9 cells, and in peripheral T lymphocytes HLA class I antigens are downregulated following infection with HIV-1. The downregulation is effected at a posttranscriptional level since the amounts of HLA class I specific mRNA are similar in infected and uninfected cells. This phenomenon is not only correlated with the state of infection, that is, the presence of P24 of HIV-1 in the cells, but also depends on the time of infection. Upon HLA class I downregulation by HIV infection, the specific lysis of peripheral blood cells by allogeneic CTL is reduced.
 ...
PMID:Downregulation of HLA class I antigens in HIV-1-infected cells. 257 99

A variety of clinical syndromes, including AIDS and neurological disorders, may follow as a consequence of infection with the human immunodeficiency virus type 1 (HIV-1). It is not yet clear, however, to what extent the destruction of lymphocytes and neural cells associated with these conditions is caused by adverse immune responses to HIV-1 or how much is due to cytopathic effects of the virus itself. Here we document the existence of HLA-restricted, HIV-1-specific cytotoxic T lymphocytes in the cerebrospinal fluid of two AIDS patients manifesting neurologic disorders. These cytotoxic T lymphocytes showed dual specificity, recognizing target cells coated with purified HIV-1 envelope glycoprotein (gp 120) or inactivated HIV-1 in the context of HLA antigens. Cytotoxic T-cell clones derived from one of the AIDS patients revealed restriction specificities representing both HLA class I and HLA class II antigens. Considerable phenotypic heterogeneity was observed amongst these clones, some expressing conventional combinations of cytotoxic T-cell surface markers, and others displaying unusual phenotypes. The presence of HIV-specific cytotoxic T lymphocytes in AIDS patients, and in particular in their cerebrospinal fluid, suggests that these cytotoxic effectors may participate in the lymphoid cell and/or neurologic damage observed in such patients.
 ...
PMID:Phenotypic heterogeneity of cerebrospinal fluid-derived HIV-specific and HLA-restricted cytotoxic T-cell clones. 284 92

The anti-HLA reactivity of sera from 210 heroin addicts was tested by the direct binding with 125I-labeled preparations of HLA class I and class II molecules purified from human B-cell lines of various HLA haplotypes. A high proportion (81.7%) of the sera tested possessed anti-HLA class I and II reactivity. The reactivity did not show any allospecificity and was apparently mediated by antibodies. The control included 100 healthy blood donors, 25 male homosexuals positive for anti-HIV (human immunodeficiency virus) antibodies, and 25 patients positive for HBsAg (hepatitis B surface antigen). Of these controls, only one of the healthy blood donors was positive for anti-HLA reactivity (P much less than 0.001). Among heroin addicts, the reactivity was independent of the presence of either HBsAg or anti-HIV antibodies in the serum.
 ...
PMID:A high proportion of sera of heroin addicts possesses anti-HLA class I and class II reactivity. 333 95

HLA class I and class II antigens circulate in serum as soluble molecules. Increased concentrations of soluble HLA class I molecules have been demonstrated in viral diseases, in rejection episodes following organ transplantation and in graft versus host disease. To explore the possibility of a variation of the serum concentrations of soluble HLA class II molecules in the same pathologic conditions we developed a double determinant immune assay that detects whole soluble HLA-DR molecules (sHLA-DR). The mean level of sHLA-DR antigens in sera from 23 healthy individuals was 0.64 +/- 0.72 microgram/ml. Elevated serum concentrations of sHLA-DR molecules were detected in sera from HIV infected patients in CDC2/3 and in CDC4 C1 stages (2.0 +/- 1.7 micrograms/ml and 4.6 +/- 1.7 micrograms/ml, respectively), in sera from patients affected by acute rejection after liver transplantation (5.3 +/- 3.7 micrograms/ml) and in sera from patients affected by severe acute graft versus host disease following bone marrow transplantation (8.8 +/- 3.1 micrograms/ml). The increase of sHLA-DR molecules in these sera significantly correlated with the elevation of soluble HLA class I antigens (P = 0.0004). The reported data suggest that both soluble HLA class I and class II molecules serum levels increase during viral infections and strong immune reactions and could suggest the involvement of these molecules in immunoregulation.
 ...
PMID:Increased serum concentration of soluble HLA-DR antigens in HIV infection and following transplantation. 748 4

Cross-reactive antibodies to HLA class I and HIV-1 gp120 were detected in the sera of HIV-1-positive individuals, and were found to share the same epitope specificity as a gp120-HLA class I cross-reactive monoclonal antibody (M38). The amino acid residues of HLA recognized by both M38 and the patient antibodies occur as a clustered pair in the HLA-C alpha 1 domain. These sequences (KYKR and RKLR) are shared by almost all HLA-C alleles and are available to antibody binding only on beta 2-microglobulin-dissociated HLA heavy chains expressed on activated cells. Similar to M38, the antibody-binding sites on HIV-1 gp120 were mapped to two noncontiguous stretches of amino acids (KYK and KAKR), which flank a hydrophobic area of the immunodominant C5 region involved in gp41 binding. Serum antibodies immunoaffinity purified on synthetic HLA and gp120 peptides representing the M38-reactive regions were shown to bind to both HLA and gp120 in Western blot, as well as to membrane-bound HLA heavy chains, and to exhibit selective complement-mediated lysis of activated T cells. No serum antibodies could be detected that bind to the gp120 C5 region (peptide IEPLGVAPT) flanked by the two HLA-like sequences.
 ...
PMID:Human antibodies to immunodominant C5 region of HIV-1 gp120 cross-react with HLA class I on activated cells. 751 59

CD4, a lymphocyte surface glycoprotein, serves as co-receptor for antigen with the T cell receptor (TCR). It is also the lymphocyte receptor for HIV by binding the gp120 viral envelope protein. Interaction of gp120 with CD4 is crucial for viral infection, but is not sufficient to allow viral entry into cells. Recombinant gp120 alters CD4+ T cell responsiveness to activation stimuli. To express its co-receptor function fully, CD4 must be laterally associated with the TCR and CD45 to form multi-receptor complexes competent to transduce potent activation signals. Here, we examine the possibility that gp120/CD4 binding alters lateral associations of CD4 with other lymphocyte surface molecules, and that assembly of abnormal multi-molecular complexes is involved in the gp120-induced CD4+ T cell dysfunction and in viral entry. In the absence of gp120, CD4 displayed high association with CD3, CD5, CD45RC, CD25, CD28, CD44, and CD53; weak association with CD2, CD38, CD45RB, CD62L, and CD26; and no association with CD45RA, CD45RO, CD11b, CD11a, CD54, CD7, CD48, CD98, CD59 CD55, HLA class I and class II molecules. Treatment with gp120 significantly increased CD4 association with CD3, CD45RA, CD45RB, CD59, CD38, CD26 and HLA class I, and decreased that with CD45RC. Specificity of these results were assessed at various levels. First, gp120 did not influence lateral associations displayed by other molecules, such as HLA class II. Second, the Leu3 mAb which binds CD4 on a site overlapping the gp120 binding site, did not elicit the same CD4 lateral associations as gp120, and finally, a direct gp120/CD4+ interaction was needed to induce the lateral associations, as shown by the observation that blocking the gp120/CD4 binding by the Leu3 mAb inhibited the gp120-induced associations. These results can be interpreted in several ways gp120/CD4 interaction could trigger an inside-out signal responsible for the associations, or gp120 could induce steric modifications of CD4 that increase its affinity for the associating molecules. Alternatively, these molecules may interact directly with gp120, bridging them with CD4. It is also possible that th e associations may be mediated by additional components, interacting with both gp120 and the associating surface molecule. The last hypothesis is likely for CD59, whose gp120-induced association with CD4 required the presence of serum in the co-capping assay. Since both CD59 and gp120 bind complement, the observed association could be mediated by complement components.
 ...
PMID:Modulation of CD4 lateral interaction with lymphocyte surface molecules induced by HIV-1 gp120. 753 55

Cellular adhesion molecules, such as ICAM-1, -2, and -3; LFA-1; and HLA class I and II are incorporated into HIV-1 virions during budding from infected cells. These virion-associated molecules can be involved in the adsorption to susceptible cells displaying the corresponding counterligands. A number of cytokines have been shown to upregulate the cellular expression of adhesion molecules, such as ICAM-1 and HLA-DR. In this study we investigated the effects of IFN-gamma on the incorporation of ICAM-1, LFA-1, and HLA-DR into mature HIV-1 progeny from chronically infected cells. The ability of such virus progeny to infect either CD4-positive or -negative cells was also investigated. The results indicate that IFN-gamma stimulates the expression of ICAM-1 and of HLA-DR on HIV-1-infected cells, whereas LFA-1 expression is unaffected. The same modifications were also observed on virus progeny, because specific MAbs to ICAM-1 and HLA-DR captured infectious HIV-1 from IFN-treated cells with higher efficiency as compared to virus from control cells, whereas virus binding to anti LFA-1 MAb was unchanged. Moreover, the HIV-1 progeny released from IFN-treated cells showed an increased ability to bind to and to infect CD4-negative cells, whereas the infectivity was basically unchanged for CD4-positive cells. Our results suggest that cytokines, as well as other soluble factors, may expand the host cell range of HIV-1, possibly through modifications of the cell-derived surface molecules on the virions.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:HIV type 1 grown on interferon gamma-treated U937 cells shows selective increase in virion-associated intercellular adhesion molecule 1 and HLA-DR and enhanced infectivity for CD4-negative cells. 757 10


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>