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

Expression vectors based on DNA or plus-stranded RNA viruses are being developed as vaccine carriers directed against various pathogens. Less is known about the use of negative-stranded RNA viruses, whose genomes have been refractory to direct genetic manipulation. Using a recently described reverse genetics method, we investigated whether influenza virus is able to present antigenic structures from other infectious agents. We engineered a chimeric influenza virus which expresses a 12-amino-acid peptide derived from the V3 loop of gp120 of human immunodeficiency virus type 1 (HIV-1) MN. This peptide was inserted into the loop of antigenic site B of the influenza A/WSN/33 virus hemagglutinin (HA). The resulting chimeric virus was recognized by specific anti-V3 peptide antibodies and a human anti-gp120 monoclonal antibody in both hemagglutination inhibition and neutralization assays. Mice immunized with the chimeric influenza virus produced anti-HIV antibodies which were able to bind to synthetic V3 peptide, to precipitate gp120, and to neutralize MN virus in human T-cell culture system. In addition, the chimeric virus was also capable of inducing cytotoxic T cells which specifically recognize the HIV sequence. These results suggest that influenza virus can be used as an expression vector for inducing both B- and T-cell-mediated immunity against other infectious agents.
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PMID:Chimeric influenza virus induces neutralizing antibodies and cytotoxic T cells against human immunodeficiency virus type 1. 769 83

Complexes of five peptides (from HIV-1, influenza A virus, HTLV-1, and hepatitis B virus proteins) bound to the human class I MHC molecule HLA-A2 have been studied by X-ray crystallography. While the peptide termini and their second and C-terminal anchor side chains are bound similarly in all five cases, the main chain and side chain conformations of each peptide are strikingly different in the center of the binding site, and these differences are accessible to direct TCR recognition. Each of the central peptide residues is seen to point up for some bound peptides, but down or sideways for others. Thus, although fixed at its ends, the structure of an MHC-bound peptide appears to be a highly complex function of its entire sequence, potentially sensitive to even small sequence differences. In contrast, MHC structural variation is relatively limited. These results offer a structural framework for understanding the role of nonanchor peptide side chains in both peptide-MHC binding affinity and TCR recognition.
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PMID:The antigenic identity of peptide-MHC complexes: a comparison of the conformations of five viral peptides presented by HLA-A2. 769 6

Periodic quantitative HIV-1 plasma cultures were performed on 28 seropositive individuals who had CD4 cells < or = 300/mm3 and who were enrolled in three clinical trials testing the efficacy of didanosine versus zidovudine monotherapy. Most plasma cultures were negative or of low titer (1-100 tissue culture infective dose/ml of plasma), but there were 14 instances of high-titered plasma viremia (> or = 1,000 tissue culture infective dose/ml of plasma) seen in 11 individuals. These peaks in plasma culture titers were significantly associated either with rapidly decreasing CD4 cell numbers or with CD4 cells already < 50/mm3. In addition, patients who experienced these episodes of high-titered plasma viremia were more apt to have clinical complaints of fever, rash, flu-like illness, and/or opportunistic infection and also the syncytium-inducing HIV-1 phenotype and progression of disease.
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PMID:Transient high titers of HIV-1 in plasma and progression of disease. 771 35

The ability of viruses to develop resistance to antiviral agents is already a major concern with respect to HIV. This article reviews mechanisms and clinical correlates of antiviral resistance and alternative drugs for treatment of infections due to resistant strains of HIV, herpes simplex virus, cytomegalovirus, varicellazoster virus, and influenza A.
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PMID:Resistance to antivirals. 776 Nov 42

We assessed the use of influenza vaccine in a cohort of HIV-infected patients during 1991 and 1992 in Los Angeles County. Influenza vaccination status and clinical and demographic data were obtained from medical records in three different outpatient clinics: a health maintenance organization (HMO), a public clinic and a private medical group. The overall proportion of patients immunized with influenza vaccine was 28%. Patients receiving medical care at the HMO were more likely to receive influenza vaccine (45%) than were patients at the public clinic (25%) or the private facility (13%). Higher immunization levels were also observed among patients with greater numbers of clinic visits for both years studied (p < 0.001). After we controlled for the number of outpatient visits, patients at the HMO and the public clinic were still more likely to receive influenza vaccine in both 1991 (adjusted relative risks 3.2 and 2.1, respectively) and 1992 (adjusted relative risks 1.7 and 1.8) compared with private clinic patients. Health-care providers should increase efforts to provide influenza vaccine to HIV-infected patients.
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PMID:Influenza immunization for HIV-infected persons in Los Angeles. 779 35

Early intervention for persons infected with human immunodeficiency virus (HIV) involves characterization of the stage of HIV disease, institution of therapy to prevent associated infections and postpone deterioration of immune function, and assistance in preventing transmission of the virus. This review examines the available data on the efficacy of current recommendations regarding the evaluation and management of persons with early HIV infection. Existing evidence supports the efficacy of physical examination, monitoring of the CD4+ cell count, tuberculin testing (with chemotherapy for persons who test positive), anergy testing, Papanicolaou testing and screening for gonorrhea and chlamydial infection (for high-risk women), screening for syphilis, antiretroviral therapy (for symptomatic patients), and guidance in reducing the transmission of HIV. Recommended measures for which evidence of clinical efficacy is less certain include immunization against infections due to influenza virus, Streptococcus pneumoniae, Haemophilus influenzae, and hepatitis B virus as well as antiretroviral therapy for asymptomatic persons. Quantitative measurement of viral titers appears promising for the monitoring of HIV disease and antiretroviral therapy; the correlations of these titers with clinical end points need to be confirmed.
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PMID:Early intervention for persons infected with human immunodeficiency virus. 779 7

Human immunodeficiency virus type 1 (HIV-1)-infected patients (n = 335) in the US Air Force HIV Natural History Program were followed for 3 years (mean) after skin testing, immunophenotyping of CD4+ cell subsets, and measurement of in vitro interleukin-2 production after stimulation by phytohemagglutinin, alloantigens, tetanus toxoid, and influenza A virus. The T cell functional assay predicted survival time (P < .001) and time for progression to AIDS (P = .014). Skin testing for tetanus, mumps, and Candida antigen and the total number of positive tests (P < .001 for each) stratified patients for survival time. In a multivariable proportional hazards model, the T cell functional assay (P = .008), the absolute number of CD4+ T cells (P = .001), the percentage of CD4+ CD29+ cells (P = .06), and the number of reactive skin tests (P < .001) predicted survival time. Thus, cellular immune functional tests have significant predictive value for survival time in HIV-1-infected patients independent of CD4+ cell count.
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PMID:In vitro T cell function, delayed-type hypersensitivity skin testing, and CD4+ T cell subset phenotyping independently predict survival time in patients infected with human immunodeficiency virus. 779 48

False-positive enzyme immunoassay (EIA) tests in blood donors receiving influenza vaccine were first reported in 1991. We conducted follow-up testing for 6 months of those donors with multiply reactive, but unconfirmed EIA (at least 2 positives in anti-HCV-1.0, anti-HIV-1, and anti-HTLV-I assays) with a history of recent flu vaccine to determine the duration of false positivity. Of 133,000 donors tested, 16 met study criteria; all 16 were reactive for anti-HCV, 10 were reactive for anti-HIV-1, and 12 were reactive for anti-HTLV-I. Fifteen donors were available for follow-up testing (using the original screening and supplemental tests): 10 (67%) reverted to negative for the 3 tests and 5 remained false positive for various markers at last sampling (3-6 months after vaccination). The mean duration of false positivity for those reverting to negative EIA test status, was 4.2 months (range 2-7 months) indicating a transient phenomenon and supporting studies which suggest a role for IgM in the mechanism.
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PMID:Donor follow-up of influenza vaccine-related multiple viral enzyme immunoassay reactivity. 780 10

Several new analogues of the novel anti-HIV agent cosalane have been synthesized and evaluated as inhibitors of HIV-1 integrase and protease, HIV-1 replication, HIV-1 and HIV-2 cytopathicity, HIV-1- and HIV-2-mediated syncytium formation, and cytopathicity of a variety of human pathogenic viruses. The congeners displayed enhanced potencies relative to cosalane itself as inhibitors of HIV-1 integrase and protease. The two most potent analogues against HIV-1 integrase displayed IC50 values of 2.2 microM, while the three most potent compounds against HIV-1 protease had IC50 values in the 0.35-0.39 microM range. In addition to its activity against HIV-1 and HIV-2 cytopathicity, cosalane inhibited the cytopathic effects of herpes simplex virus-1, herpes simplex virus-2, and human cytomegalovirus at concentrations that were well below the cytotoxic concentrations. Potentially useful antiviral activities were also revealed for some of the new cosalane congeners against influenza virus, Junin virus, and Tacaribe virus.
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PMID:Cosalane analogues with enhanced potencies as inhibitors of HIV-1 protease and integrase. 785 37

Direct DNA inoculation induces immune responses through the delivery of nonreplicating transcription units that drive the synthesis of specific foreign proteins within the inoculated host. These proteins are processed within host cells and through association with relevant MHC antigens that can become the subject of immune surveillance and elicit immune responses against pathogens. Direct introduction of DNA into mice has been reported to be antigenic as demonstrated by the use of this technique to develop immune responses against human growth hormone, influenza proteins, as well as HIV-1 proteins. Most recently the demonstration of the use of this technology to produce anti-HIV-1 immune responses has been reported in nonhuman primates. Accordingly a more detailed analysis of this technology could generate important insight into the generality of this approach for immune therapy or vaccine design. In this article we further our investigation of direct DNA inoculation as a tool for induction of relevant immune responses against HIV-1 in vivo. We demonstrate expression of HIV-1 antigens in the inoculated muscle of animals. Inoculated animals demonstrate significant cytotoxic T cell responses against HIV-1 antigen-expressing targets. Furthermore, using a novel challenge system, we demonstrate that the majority of immunized animals can reject lethal, HIV-1 antigen-expressing cell challenge in an antigen-specific manner. This technology has relevance for the development of immunization strategies against HIV as it provides for specific antigen production in vivo without the use of infectious agents.
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PMID:DNA inoculation induces protective in vivo immune responses against cellular challenge with HIV-1 antigen-expressing cells. 786 31


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