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HIV Antigen (hiv + antigen)
Selected AbstractsDendritic cell-based human immunodeficiency virus vaccineJOURNAL OF INTERNAL MEDICINE, Issue 1 2009C. R. Rinaldo Abstract. Dendritic cells (DC) have profound abilities to induce and coordinate T-cell immunity. This makes them ideal biological agents for use in immunotherapeutic strategies to augment T-cell immunity to HIV infection. Current clinical trials are administering DC-HIV antigen preparations carried out ex vivo as proof of principle that DC immunotherapy is safe and efficacious in HIV-infected patients. These trials are largely dependent on preclinical studies that will provide knowledge and guidance about the types of DC, form of HIV antigen, method of DC maturation, route of DC administration, measures of anti-HIV immune function and ultimately control of HIV replication. Additionally, promising immunotherapy approaches are being developed based on targeting of DC with HIV antigens in vivo. The objective is to define a safe and effective strategy for enhancing control of HIV infection in patients undergoing antiretroviral therapy. [source] Incremental detection of HIV infections by the HIV antigen/antibody combination assays: An Australian experience,JOURNAL OF MEDICAL VIROLOGY, Issue S1 2007Philip Cunningham Abstract Detection of acute cases of human immunodeficiency virus (HIV) infection by the direct detection of HIV antigen or HIV nucleic acid assays is well known with an estimated 5,9 days reduction in the pre-seroconversion ,window period' by the detection of HIV specific antibodies. The aim of this study was to observe the impact following routine introduction of a screening assay which simultaneously detects HIV (type 1 & 2) antigen and antibody on the yield of acute HIV infection in multiple sites servicing different patient populations with a varying range of risk factors associated with HIV acquisition. During the first year (2003,2004), a total of 27 cases of acute HIV-1 infection were identified by the HIV-1/2 Ab/Ag combo test which were confirmed to be detectable for HIV antigen only that may have gone undetected should an HIV-1/2 antibody only assay have been used. Specimens referred from higher HIV case load centers were more likely to have provided relevant clinical information consistent with acute retroviral syndrome and relevant history of risk however there were numerous cases where no clinical information was provided. This study shows that routine introduction of HIV-1/2 antigen/antibody screening assays increases the identification of acute cases of HIV infection in low prevalence setting and may represent an important tool for enhanced surveillance of incident HIV infection and opportunities for prevention. J. Med. Virol. 79:S16,S22, 2007. © 2007 Wiley-Liss, Inc. [source] HIV antigen,antibody combination enzyme immunoassay,the experience of a London Teaching HospitalJOURNAL OF MEDICAL VIROLOGY, Issue S1 2007Simon Goldenberg Abstract The introduction of the fourth generation HIV antigen,antibody combination enzyme immunoassay (HIV Ag,Ab EIA) has led to a reduction in the diagnostic "window period" when HIV antibody is negative during primary infection. This facilitates earlier laboratory diagnosis during sero-conversion. An HIV Ag,Ab EIA (AxSYM, Abbott Laboratories, Kent, UK) was introduced to a London Teaching Hospital since 2004 as the primary screening test. Confirmation was performed using another HIV Ag,Ab EIA (Vironostika, BioMérieux, Hampshire, UK) and an HIV Ab only assay (Bispot, Orgenics, Yavne, Israel). Retrospective analysis identified a total of 20 sero-converting patients who would have been missed if the standard antibody-only HIV tests had been used as the primary screening test. This accounted for approximately 3% of the new diagnoses made by the laboratory. The median time from onset of illness to sero-conversion was 18 days. Two patients had multiple samples analyzed between initial presentation and eventual sero-conversion. One had a prolonged sero-conversion illness lasting for over 137 days; the other sero-converted within 17 days. A plotting of the signal to cut-off ratio with time of the two HIV Ag,Ab EIAs showed a V-shaped curve and both tests were below cut-off at some time-points during sero-conversion. These two cases highlighted the difficulties in diagnosing HIV infection during sero-conversion. On the basis of these results, it is recommended that a fourth generation HIV Ag,Ab EIA could be considered for use as the standard of care, particularly in any population with a high rate of HIV infection. J. Med. Virol. 79:S23,S26, 2007. © 2007 Wiley-Liss, Inc. [source] Efficient mucosal delivery of the HIV-1 Tat protein using the synthetic lipopeptide MALP-2 as adjuvantEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2003Stefan Borsutzky Abstract A major requirement for HIV/AIDS research is the development of a mucosal vaccine that stimulates humoral and cell-mediated immune responses at systemic and mucosal levels, thereby blocking virus replication at the entry port. Thus, a vaccine prototype based on biologically active HIV-1 Tat protein as antigen and the synthetic lipopeptide, macrophage-activating lipopeptide-2 (MALP-2), asa mucosal adjuvant was developed. Intranasal administration to mice stimulated systemic and mucosal anti-Tat antibody responses, and Tat-specific T cell responses, that were more efficient than those observed after i.p. immunization with Tat plus incomplete Freund's adjuvant. Major linear B cell epitopes mapped within aa 1,20 and 46,60, whereas T cell epitopes were identified within aa 36,50 and 56,70. These epitopes have also been described in vaccinated primates and in HIV-1-infected individuals with better prognosis. Analysis of the anti-Tat IgG isotypes in serum, and the cytokine profile of spleen cells indicated that a dominant Th1 helper response was stimulated by Tat plus MALP-2, as opposed to the Th2 response observed with Tat plus incomplete Freund's adjuvant. Tat-specific IFN-,-producing cells were significantly increased only in response to Tat plus MALP-2. These data suggest that Malp-2 may represent an optimal mucosal adjuvant for candidate HIV vaccines based on Tat alone or in combination with other HIV antigens. [source] Dendritic cell-based human immunodeficiency virus vaccineJOURNAL OF INTERNAL MEDICINE, Issue 1 2009C. R. Rinaldo Abstract. Dendritic cells (DC) have profound abilities to induce and coordinate T-cell immunity. This makes them ideal biological agents for use in immunotherapeutic strategies to augment T-cell immunity to HIV infection. Current clinical trials are administering DC-HIV antigen preparations carried out ex vivo as proof of principle that DC immunotherapy is safe and efficacious in HIV-infected patients. These trials are largely dependent on preclinical studies that will provide knowledge and guidance about the types of DC, form of HIV antigen, method of DC maturation, route of DC administration, measures of anti-HIV immune function and ultimately control of HIV replication. Additionally, promising immunotherapy approaches are being developed based on targeting of DC with HIV antigens in vivo. The objective is to define a safe and effective strategy for enhancing control of HIV infection in patients undergoing antiretroviral therapy. [source] Failure to confirm HIV infection in two end-stage HIV/AIDS patients using a popular commercial line immunoassayJOURNAL OF MEDICAL VIROLOGY, Issue 9 2008Julian W. Tang Abstract Immunoassays using either viral lysate (Western blot) or recombinant/synthetic antigen (immunoblot) for anti-HIV capture are still the preferred method to confirm HIV infection. Two cases of HIV-1-infected patients presented with acquired immunodeficiency syndrome (AIDS)-defining illnesses. Laboratory tests were performed using multiple commercial HIV test kits on multiple sera from both patients over several weeks. Both patients were strongly positive on the anti-HIV/p24 antigen combined screening assay. Yet, HIV-1 infection could not be confirmed using a popular commercial immunoassay. Eventually, HIV infection was confirmed using an alternative commercial Western blot assay as well as an HIV quantitative PCR test. In laboratories without nucleic acid testing (NAT) for HIV, indeterminate results may delay confirmation of HIV infection, if commercial line immunoassays alone are available. Some end-stage HIV/AIDS patients may not produce antibodies to specific HIV antigens and may therefore give indeterminant or negative results on some immunoassays, depending on the type of antigen used. This report highlights the utility of having NAT available when diagnosing difficult cases of HIV infection, especially in light of the recent Centers for Disease Control and Prevention move towards more universal, routine, HIV testing. J. Med. Virol. 80:1515,1522, 2008. © 2008 Wiley-Liss, Inc. [source] Comparison of intranasal with targeted lymph node immunization using PR8-Flu ISCOM adjuvanted HIV antigens in macaquesJOURNAL OF MEDICAL VIROLOGY, Issue 5 2007G. Koopman Abstract The rapidly spreading HIV epidemic requires a vaccine that elicits potent mucosal immunity to halt or slow transmission. Induction of these responses will depend on the use of appropriate adjuvants and targeting of the mucosal immune system. Previously, immune stimulating complexes (ISCOM) have shown great potency as adjuvant in the induction of mucosal responses in mice and systemic responses in non-human primates. In this study, HIV formulated in PR8-Flu ISCOM adjuvant was applied to immunize rhesus macaques against HIV; targeting the mucosa either via intranasal (IN) application or via targeted lymph node immunization (TLNI). While, strong systemic, HIV specific, cytokine, lymphoproliferative, and antibody responses were induced via the TLNI route, the IN application generated only low responses. Furthermore, all four animals immunized via TLNI developed vaginal IgA antibodies against gp120. In conclusion, in contrast to what has been demonstrated in mice, the IN application of PR8-Flu ISCOM did not induce strong immune responses in rhesus macaques unlike those immunized by the TLNI route. J. Med. Virol. 79:474,482, 2007. © 2007 Wiley-Liss, Inc. [source] | ||||||||||