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

A randomized, double blind, placebo controlled Phase I trial of a prototype human immunodeficiency virus type 1 (HIV-1) synthetic peptide vaccine was conducted in Bangkok, Thailand, to evaluate the safety and immunogenicity of the vaccine in a population of healthy adults at low risk for HIV infection, and to establish essential infrastructure for future HIV vaccine trials in Thailand. Thirty volunteers (25 males; 5 females) were recruited and randomized into 3 groups, receiving 3 intramuscular injections of either 100 micrograms vaccine (N = 12) or 500 micrograms vaccine (N = 12) or alum placebo (N = 6) on weeks 0, 4 and 25. The vaccine was well tolerated without any serious adverse effects. HIV-1 specific ELISA responses were detected in 20/24 subjects who received the vaccine, with V3 binding antibody titers ranging from 1:69 to 1:5,041. HIV-1 (MN) specific neutralizing antibody was detected in 19/20 of subjects with detectable HIV-1 specific binding antibody. Neutralization titers ranged from 1:14 to 1:1,294, which were less than titers observed in HIV-infected subjects. The results of this study indicate that the vaccine was well tolerated, and that the vaccine stimulated anti-HIV humoral immune responses in Thai subjects. The successful undertaking of this first HIV vaccine trial conducted in Thailand provided important preparatory information surrounding volunteer recruitment and motivations, and paves the way for future trials of HIV vaccines in Thailand.
Asian Pac J Allergy Immunol 1997 Mar
PMID:International clinical trials of HIV vaccines: I. Phase I trial of an HIV-1 synthetic peptide vaccine in Bangkok, Thailand. 925 47

Phenylalanyl-pyrrolidine-2 nitrile (Phe-pyrr-2-CN) and arginyl(PMC)-pyrrolidine-2-nitrile (Arg(PMC)-pyrr-2-CN) are two dipeptidyl peptidase IV/CD26 (DPP-IV/CD26) inhibitors designed and synthesized by our group. These two compounds suppress the enzymatic activity of DPP-IV/CD26 in a competitive and reversible manner. Pretreatment of CEM cells with either of the compounds yielded a marked albeit transient reduction of HIV infection, as measured by HIV1 p24 production, RT activity and syncytium formation. The ID50 value of the Phe-Pyrr-2-CN and Arg(PMC)-pyrr-2-CN in HIV1 inhibition was 5.3 microM and 2.4 microM, respectively. Administration of either of the DPP-IV/CD26 inhibitors 1 h after HIV1 infection did not suppress HIV1 production. An analog whose inhibitory activity toward DPP-IV/CD26 was abolished by blocking the N-terminal of Phe-pyrr-2-CN with the 9-fluorenymethyloxycarbonyl (Fmoc) group had no effect on HIV1 infection. An additive effect of HIV1 inhibition was observed in combinations of either of the DPP-IV/CD26 inhibitors with CD4 monoclonal antibody. These results suggest that DPP-IV/CD26 enzymatic activity may play a role in facilitating HIV1 infection of human CD4+T cells at the entry process. DPP-IV/CD26 inhibitors may therefore have potential use in combination with other drugs to prevent HIV1 transmission.
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PMID:Inhibition of human immunodeficiency virus type 1 infection in a T-cell line (CEM) by new dipeptidyl-peptidase IV (CD26) inhibitors. 927 76

A Phase 1, double-blind, placebo controlled trial was conducted in Longchuan County, China, to evaluate the safety and immunogenicity of a prototype HIV-1 synthetic peptide vaccine in a target population at risk for HIV infection, and to establish the infrastructure for future large-scale HIV vaccine efficacy trials. Subjects were randomly assigned to receive 100 microg or 500 microg of vaccine or alum placebo, and were given three injections at an accelerated 0, 1, and 2 month schedule. The vaccine was well tolerated with no significant local or systemic reactions observed in any subjects. Fifty-five percent (100 microg dose) and 64% (500 microg dose) of subjects who received the vaccine produced binding antibody to the immunogen as determined by ELISA. However, HIV-1 (MN) neutralizing antibody was detected in only 23% (3/13) of subjects with detectable HIV-1 specific binding antibody. It was concluded that this prototype HIV-1 synthetic peptide vaccine was well tolerated, safe and immunogenic, and that a 0, 1, 2 month schedule was not as effective in stimulating HIV-1 specific neutralizing antibodies compared with previous trials utilizing a 0, 1, 6 month schedule. Finally, this trial demonstrated that well-designed HIV vaccine trials can be performed at this clinical trials site in Yunnan, China, and that this site should be considered for conducting larger safety, immunogenicity and efficacy trials of candidate HIV vaccines.
Asian Pac J Allergy Immunol 1997 Jun
PMID:International clinical trials of HIV vaccines: II. phase I trial of an HIV-1 synthetic peptide vaccine evaluating an accelerated immunization schedule in Yunnan, China. 934 75

Flow cytometer (FACScan) was used to determine the range of T lymphocyte subpopulations in normal Thai blood donors at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai. Reference population consisted of 150 healthy HIV seronegative blood donors. T lymphocyte subsets were analysed using two-color immunophenotyping of peripheral blood lymphocytes with a lysed whole blood technique and enumerated. The study showed that the normal values for CD3+ lymphocytes (percent), CD4+ lymphocytes (percent), CD8+ lymphocytes (percent), CD4/CD8 ratio, absolute CD3+ lymphocyte count, absolute CD4+ lymphocyte count and absolute CD8+ lymphocyte count were 64 +/- 8.8, 36.1 +/- 6.4, 25.7 +/- 7.3, 1.5 +/- 0.6, 1,630 +/- 600 cells/microl, 910 +/- 300 cells/microl and 670 +/- 350 cells/microl, respectively. We found that the values of CD3, CD4 and CD4/CD8 ratio were significantly lower than those in the Caucasians but those of CD8 was not significantly different. This observations have important clinical implication for the use of T lymphocyte subsets measurement, especially in the management of HIV infection in Thais. These normal ranges can be used as a reference for the decisions in clinical practice.
Asian Pac J Allergy Immunol 1997 Sep
PMID:Flow cytometric analysis of T-lymphocytes subsets in adult Thais. 943 46

CD26 is a widely distributed 110 kD cell-surface glycoprotein with known dipeptidyl-peptidase IV (DPP-IV) activity in its extracellular domain. This ecto-enzyme is capable of cleaving amino terminal dipeptides from polypeptides with either L-proline or L-alanine in the penultimate position. On human T cells, CD26 expression appears late in thymic differentiation and is preferentially restricted to the CD4+ helper/memory population, and CD26 can deliver a potent co-stimulatory T-cell activation signal. The cDNA sequence of CD26 predicts a type II membrane protein with only 6 amino acids in its cytoplasmic region, suggesting that, in addition to DPP-IV enzyme activity, other signal-inducing molecules may be associated with CD26. Considerable evidence exists that CD26 interacts, presumably in its extracellular domain, with both CD45, a protein tyrosine phosphatase, and adenosine deaminase (ADA), each of which is capable of functioning in a signal transduction pathway. In addition, CD26 is the receptor for ADA, and ADA on the cell surface is involved in an important immunoregulatory mechanism by which released ADA binds to the cell-surface ADA. This multifunctional molecule may be involved in cell migration and the HIV-1-associated loss of CD4+ cells through the process of programmed cell death. Thus, CD26 appears to play a key role in a number of aspects of lymphocyte function.
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PMID:The structure and function of CD26 in the T-cell immune response. 955 64

The diagnosis of HIV infection is based on screening of HIV antibodies and confirmed by a more specific supplementary test. The most common confirmation test is Western blot, which is expensive, time consuming and subject to technical skill. The present study was carried out to evaluate whether the anti-HIV-1 antibody titer is valid as a supplementary test for diagnosis of HIV-1 infection. Anti-HIV-1 antibody titers of 2,414 anti-HIV-1 positive sera determined by the particle agglutination (PA) method were analysed in comparison with the Western blot analysis. The Western blot negative result was found in 11 of 2,414 (0.46%) anti-HIV-1 positive sera, these sera also gave negative anti-HIV by ELISA. The PA titers of these sera were found in the range of 16 to 64. Seventeen samples (0.70%) with anti-HIV-1 in the titer range of 16 to 256 showed indeterminate Western blot analysis. The rest, 2,386 of these 2,414 sera (98.84%), were shown to be positive by Western blot. However, all of the 2,356 sera with antibody titers > or = 512 (97.6%) demonstrated positive Western blot results. Five cases among the 17 (29.4%) indeterminate sera were examples of early seroconversion of HIV infection, which were confirmed in follow up specimens. The results suggest that only the samples with antibody titers < 512 are required to be confirmed for HIV infection by Western blot. It is possible that early seroconversion may be inferred from anti-HIV titers. Therefore, in order to reduce time and cost, the PA anti-HIV titer can be used as an alternative supplementary test for diagnosis of HIV-1 infection in most positive screened anti-HIV samples. Western blot is needed for testing in only a few cases.
Asian Pac J Allergy Immunol 1997 Dec
PMID:Anti-HIV antibody titer: an alternative supplementary test for diagnosis of HIV-1 infection. 957 12

A study on how to apply PCR as a diagnostic test for the infants born to HIV-1 infected mothers is described. All steps including clinical care, blood sampling, specimen processing and PCR analysis were carried out using native facilities and personnel. An open cohort of 130 children was evaluated at birth, 1, 6, 9, 15, and 18 months of age. Definite infection status was assessed by clinical and serological data during an 18 months of follow up period. PCR results were reported as positive or negative when at least 2 concordant data were denoted. This in-house PCR, compared to known infection status, gave 100% sensitivity and 94.4% specificity within 6 months after birth. On the other hand, clinical diagnosis could identify only the infected infants at 9 months of age. The HIV-1 transmission rate from mother to infant was 23.2%. Though this PCR was not at an optimal level of specificity, it was still beneficial to identify uninfected infants in the first year of their lives and avoid unnecessary medical care. Here, we report an in-house PCR that offers good performance at low cost for the diagnosis of HIV-1 vertical transmission.
Asian Pac J Allergy Immunol 1997 Dec
PMID:Diagnosis of perinatal HIV-1 infection by in-house PCR. 957 13

The functionality of DPP-IV, purified from human placenta and isolated from CD4+/CD26+ T cells of noninfected and HIV-1-infected individuals, was investigated as to its ability to bind certain specific peptides. Using isoelectric focusing and the specificity of substrate-impregnated overlay membranes, we found that DPP-IV from term placenta and from T cells of HIV-infected individuals was significantly more sialylated compared with enzyme isozyme patterns of other tissues. We report here that (1) the number of isoforms of DPP-IV and extent of sialylation are critical to function and peptide binding; (2) the number of sialylated isoforms isolated from PBMCs increases significantly with age greater than 40 years; (3) hypersialylation by extreme anionic isoforms is highly associated with HIV infection and pathognomonic to remaining CD4+ cells in overt AIDS; and (4) highly sialylated DPP-IV is more significantly inhibited by Tat and cationic peptides. We conclude that hypersialylation of DPP-IV modifies surface charge of the CD26 antigen, promoting binding of HIV peptides through their cationic domains to the sialic acid residues of DPP-IV, and that certain HIV moieties are likely to engage this phenomenon as an auxiliary adhesion mechanism to fuse with cells. Furthermore, as a consequence of this occurrence, DPP-IV enzymatic activity can be significantly reduced, competitively.
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PMID:The significance of hypersialylation of dipeptidyl peptidase IV (CD26) in the inhibition of its activity by Tat and other cationic peptides. CD26: a subverted adhesion molecule for HIV peptide binding. 967 Dec 14

The Ministry of Health and Welfare forms the AIDS Surveillance Committee, which publishes HIV infection at two-month intervals. As at December 1993, the Ministry of Health and Welfare reported 267 AIDS cases and 1,143 HIV infection cases. Epidemiological data in Japan showed a rapid increase of cases of transmission through heterosexual contact since 1991, before which cases of transmission due to homosexual contact were relatively large in number according to reports. Sporadic cases of mother-to-child transmission and some cases due to injection of drug use were also reported. However, others/unknown cases were 449 (31.8%). Although the reported number of AIDS cases and HIV infection cases in Japan is still small, a rapidly increasing HIV epidemic is feared. It is predicted that the primary mode of transmission will be heterosexual contact and that another epidemiological characteristics will be diversified modes of transmission. Therefore, the present surveillance should continue and actively track the epidemic and provide useful information for planning prevention strategies in Japan.
Asia Pac J Public Health 1995
PMID:HIV/AIDS surveillance system and reported cases of human immunodeficiency virus infection and acquired immunodeficiency syndrome in Japan (1983-1993). 1005 Jan 82

A survey was conducted to find potential risk factors for HIV transmission through dental practice. Self-administered questionnaires were distributed to the members of the dental associations of various prefectures and small cities in Japan. A total of 747 questionnaires was returned by dentists. The findings revealed several problems. Gloves, masks, and other protective garments were generally worn, but most dentists did not always use them during the full course of treatment limiting usage to surgical treatment, and when treating patients in "high-risk groups" and in dental practice the exact percentage of the dentists who reused a used anesthetic liquid cartridge is 12.7%. The effectiveness of the education for dentists regarding AIDS was statistically clarified. It is obviously necessary to provide important information regarding AIDS and HIV transmission to the dentists. Potential risk for HIV transmission through dental practice will be prevented by AIDS education for the dentists.
Asia Pac J Public Health 1998
PMID:A survey of potential risk factors for HIV transmission through dental practice in Japan. 1005 Feb 3


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