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)

Therapeutic immunisation of human immunodeficiency virus type 1-infected individuals should be actively pursued in the first instance to augment highly active antiretroviral therapy regimens. Peptide-based immunotherapeutic strategies offer considerable advantages over conventional approaches, particularly regarding safety. Peptide design itself is becoming increasingly sophisticated, with the rapid evolution of bioinformatics tools that can analyse not only T cell epitopes, but also their potential for successful presentation on diverse human leukocyte antigen (HLA) class I or II following intracellular processing by antigen-presenting cells (APCs). By targeting conserved viral domains, peptides acquire improved reactivity to diverse viral strains. Dendritic cells represent a powerful route of administration, as they are the most potent APCs and can present exogenous peptides on both HLA class I and II through the process of cross-presentation. In this way, soluble peptides can thereby stimulate both CD4+ and CD8+ T cells.
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PMID:Novel peptide-based HIV-1 immunotherapy. 1500 29

A synthetic T cell immunogen (TCI) has been designed as a candidate DNA-based vaccine against Human immunodeficiency virus (HIV)-1 using cytotoxic T lymphocytes (CD8(+) CTL) and T-helper lymphocytes (CD4(+) Th) epitopes retrieved from the Los Alamos HIV Molecular Immunology Database. The protein 392 amino acids in length contains about eighty CTL-epitopes, many of which are overlapping and are totally restricted by ten different HLA class I molecules. To be able to detect CTL responses induced by a DNA vaccine in experimental animals, additional epitopes, restricted by mouse and Macaque rhesus major histocompatibility complex (MHC) class I molecules, were included in the target immunogen. The gene encoding the TCI protein was assembled, cloned into vector plasmids and expressed in a prokaryotic and a eukaryotic system. The presence of HIV-1 protein fragments in the immunogen structure was ascertained by ELISA and immunoblotting using panels of HIV-1-positive sera and monoclonal antibodies to p24. It has been demonstrated that DNA vaccine can induce both specific T cell responses (CTL and blast transformation) and specific antibodies in mice immunized with pcDNA-TCI.
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PMID:Designing and engineering of DNA-vaccine construction encoding multiple CTL-epitopes of major HIV-1 antigens. 1506 50

Antigen-induced cellular immunogenicity may vary between populations due to differences in human leukocyte antigen (HLA) diversity and, hence, may play a critical role in the protection afforded by vaccines. In the setting of two, phase I/II human immunodeficiency virus-1 vaccine trials of a recombinant canarypox prime, and boosting with either recombinant monomeric gp120 or oligomeric gp160, we assessed the association between specific human leukocyte antigen (HLA) class I serotypes and the presence of cytotoxic T-lymphocyte response measured by 51Cr-release assay. HLA class I serotypes A11, A24, A33, B46, and B75 were the most common, present in 10% or more of 245 individuals studied. Forty of 187 (21.4%) Thai adults who received either ALVAC-HIV with gp120 or oligomeric gp160 or ALVAC alone had a precursor cytolytic CD8 T-cell response (pCTL). HLA-B44 was positively and significantly associated with a pCTL response (odds ratio 7.6, 95% CI: 2.7-21.2), whereas B46 was negatively associated but not robust when adjusted for multiple comparisons. Responses to Env proteins accounted for the majority (nine of 11) of pCTL activity among those persons with B44. This HLA class I serotype occurred in 9.4% of participants overall (including the placebo group), less commonly than what is reported from populations of European ancestry. These results strengthen the importance of assessing HLA class I distributions in conjunction with studies of vaccines designed to elicit cellular immunity in different populations.
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PMID:HLA class I serotypes and cytotoxic T-lymphocyte responses among human immunodeficiency virus-1-uninfected Thai volunteers immunized with ALVAC-HIV in combination with monomeric gp120 or oligomeric gp160 protein boosting. 1530 5

Epidemiological and genetic correlates of Chlamydia trachomatis infection were examined prospectively in 124 male and 361 female adolescents at high risk for human immunodeficiency virus type 1 (HIV-1) infection. Seventy percent of subjects were African American, and 68% had HIV-1 infection. As expected, younger age (<17 years), multiple sex partners (> or =2), and prior chlamydial infection predicted chlamydial infection during a 6-56-month follow-up period (P=.02, P=.02, and P=.03, respectively). Human leukocyte antigen (HLA) class II variant DQB1*06 (mostly *0602 and *0603) was associated with chlamydial infection (49% vs. 34%; adjusted relative odds [RO], 1.8; P=.005), as was HLA class I haplotype B*44-Cw*04 (10% vs. 4%; RO, 3.2; P=.009). DQB1*06 was found in 9 (75%) of 12 female adolescents with chlamydial pelvic inflammatory disease. In contrast, sex, ethnicity, and HIV-1 infection did not predict chlamydial infection. These findings suggest that antigen presentation in adaptive immune responses may serve as a major factor in effective control of C. trachomatis infection. The underlying mechanisms remain to be experimentally elucidated.
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PMID:Epidemiological and genetic correlates of incident Chlamydia trachomatis infection in North American adolescents. 1549 25

The extreme polymorphism in the human leukocyte antigen (HLA) class I region of the human genome is suggested to provide an advantage in pathogen defence mediated by CD8+ T cells. HLA class I molecules present pathogen-derived peptides on the surface of infected cells for recognition by CD8+ T cells. However, the relative contributions of HLA-A and -B alleles have not been evaluated. We performed a comprehensive analysis of the class I restricted CD8+ T-cell responses against human immunodeficiency virus (HIV-1), immune control of which is dependent upon virus-specific CD8+ T-cell activity. In 375 HIV-1-infected study subjects from southern Africa, a significantly greater number of CD8+ T-cell responses are HLA-B-restricted, compared to HLA-A (2.5-fold; P = 0.0033). Here we show that variation in viral set-point, in absolute CD4 count and, by inference, in rate of disease progression in the cohort, is strongly associated with particular HLA-B but not HLA-A allele expression (P < 0.0001 and P = 0.91, respectively). Moreover, substantially greater selection pressure is imposed on HIV-1 by HLA-B alleles than by HLA-A (4.4-fold, P = 0.0003). These data indicate that the principal focus of HIV-specific activity is at the HLA-B locus. Furthermore, HLA-B gene frequencies in the population are those likely to be most influenced by HIV disease, consistent with the observation that B alleles evolve more rapidly than A alleles. The dominant involvement of HLA-B in influencing HIV disease outcome is of specific relevance to the direction of HIV research and to vaccine design.
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PMID:Dominant influence of HLA-B in mediating the potential co-evolution of HIV and HLA. 1559 17

Human immunodeficiency virus (HIV)-1 amino acid sequence polymorphisms associated with expression of specific human histocompatibility leukocyte antigen (HLA) class I alleles suggest sites of cytotoxic T lymphocyte (CTL)-mediated selection pressure and immune escape. The associations most frequently observed are between expression of an HLA class I molecule and variation from the consensus sequence. However, a substantial number of sites have been identified in which particular HLA class I allele expression is associated with preservation of the consensus sequence. The mechanism behind this is so far unexplained. The current studies, focusing on two examples of "negatively associated" or apparently preserved epitopes, suggest an explanation for this phenomenon: negative associations can arise as a result of positive selection of an escape mutation, which is stable on transmission and therefore accumulates in the population to the point at which it defines the consensus sequence. Such negative associations may only be in evidence transiently, because the statistical power to detect them diminishes as the mutations accumulate. If an escape variant reaches fixation in the population, the epitope will be lost as a potential target to the immune system. These data help to explain how HIV is evolving at a population level. Understanding the direction of HIV evolution has important implications for vaccine development.
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PMID:Transmission and accumulation of CTL escape variants drive negative associations between HIV polymorphisms and HLA. 1578 81

We have previously showed that long-term intake of Korean red ginseng (KRG) delayed disease progression in human immunodeficiency virus type 1 (HIV-1)-infected patients. In the present study, to investigate whether this slow progression was affected by KRG intake alone or in combination with HLA factor, we analyzed clinical data in 68 HIV-1-infected patients who lived for more than 5 years without antiretroviral therapy. The average KRG intake over 111.9 +/- 31.3 months was 4,082 +/- 3,928 g, and annual decrease in CD4 T cells was 35.0 +/- 28.7/microl. Data analysis showed that there are significant inverse correlations between the HLA prognostic score (0.29 +/- 1.19) and annual decrease in CD4 T cells (r = -0.347; P < 0.01) as well as between the amount of KRG intake and annual decrease in CD4 T cells (r = -0.379; P < 0.01). In addition, KRG intake significantly slowed the decrease in CD4 T cells even when influence of HLA class I was statistically eliminated (repeated-measure analysis of variance; P < 0.05). We also observed significant correlation between KRG intake and a decrease in serum-soluble CD8 antigen level (r = 0.62; P < 0.001). In conclusion, these data show that KRG intake independently and significantly affected the slow depletion of CD4 T cells irrespective of HLA class I.
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PMID:Korean red ginseng slows depletion of CD4 T cells in human immunodeficiency virus type 1-infected patients. 1581 56

We report familial Hodgkin lymphoma (FHL) in a family with five children, of which three were human leucocyte antigen (HLA) class I identical. These three siblings were diagnosed with Epstein-Barr virus (EBV)-positive Hodgkin lymphoma within a 6-year period. All three were treated with chemo- and/or radiotherapy and are presently in complete remission. None of the children had evidence of overt immunodeficiency or autoimmune disease. This case contributes to the existing material on FHL and implies a role for both HLA class I antigens and EBV infection of the tumour cell population in the pathogenesis of some cases of FHL.
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PMID:Epstein-Barr virus-associated familial Hodgkin lymphoma: paediatric onset in three of five siblings. 1591 83

Susceptibility to HIV-1 infections is, beside other factors, determined by individual host genetic variants like HLA class I alleles, CCR5 and CCR2 variants and levels of CCR5 binding chemokines. A new approach to determine the individual risk of acquiring an HIV infection or to estimate the disease progression could now be possible. In a recent study, a significant interindividual and interpopulation difference in the copy number of a segmental duplication encompassing the gene encoding CCL3L1, a potent human immunodeficiency virus-1 (HIV- 1)-suppressive chemokine was found. Possession of a CCL3L1 copy number lower than the population average was associated with markedly enhanced HIV/acquired immunodeficiency syndrome (AIDS) susceptibility. This could lead to a screening test that identifies people who have a higher or lower susceptibility to HIV/ AIDS, potentially enabling clinicians to adapt treatment regimens. Also, this is particularly important for assessment of the efficacy of a protective vaccine.
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PMID:Susceptibility to HIV/AIDS: an individual characteristic we can measure? 1594 Apr 20

Several HLA class I alleles have been associated with slow human immunodeficiency virus (HIV) disease progression, supporting the important role HLA class I-restricted cytotoxic T lymphocytes (CTL) play in controlling HIV infection. HLA-B63, the serological marker for the closely related HLA-B*1516 and HLA-B*1517 alleles, shares the epitope binding motif of HLA-B57 and HLA-B58, two alleles that have been associated with slow HIV disease progression. We investigated whether HIV-infected individuals who express HLA-B63 generate CTL responses that are comparable in breadth and specificity to those of HLA-B57/58-positive subjects and whether HLA-B63-positive individuals would also present with lower viral set points than the general population. The data show that HLA-B63-positive individuals indeed mounted responses to previously identified HLA-B57-restricted epitopes as well as towards novel, HLA-B63-restricted CTL targets that, in turn, can be presented by HLA-B57 and HLA-B58. HLA-B63-positive subjects generated these responses early in acute HIV infection and were able to control HIV replication in the absence of antiretroviral treatment with a median viral load of 3,280 RNA copies/ml. The data support an important role of the presented epitope in mediating relative control of HIV replication and help to better define immune correlates of controlled HIV infection.
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PMID:HLA-B63 presents HLA-B57/B58-restricted cytotoxic T-lymphocyte epitopes and is associated with low human immunodeficiency virus load. 1605 15


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