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

Eleven of 27 haemophilic boys who received a common batch of Factor VIII concentrate subsequently developed acute hepatitis B; although 9 were considered not to have been previously exposed to the virus, 2 other boys had been considered immune to hepatitis B. The amount of concentrate received by each child, together with their HIV-antibody status and T-lymphocyte subset distribution prior to exposure, did not influence their response to the hepatitis B virus (HBV). The two previously immune children who became infected, however, had evidence of the HIV-associated persistent generalized lymphadenopathy syndrome. Detailed investigation of the suspect batch of concentrate revealed hepatitis B surface antibody to a titre of 112 miu/ml, but surface antigen was not detectable, even after dissociation of antigen and antibody. As a result of this outbreak, 5 of the 11 boys remain carriers of the virus and 2 other family members have contracted acute hepatitis B. The possibility that the response of the haemophiliacs to HBV may be altered due to acquired alteration of their immune function is discussed. Regular screening of haemophiliacs, including those immune to hepatitis B, is recommended, since even with regular donor screening, HBV remains a major infective risk to haemophiliacs receiving Factor VIII replacement therapy, and the risk to an individual may change with time.
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PMID:Change in immune response to hepatitis B in boys with haemophilia. 313 29

Following acute hepatitis B virus (HBV) infection, most individuals develop antibodies to HBV surface (anti-HBs) and core antigen (anti-HBc). Prevalence studies have shown that 10-18% develop anti-HBc in the absence of detectable anti-HBs. We report four such cases, all with persistence of serum anti-HBc, who had evidence of a second period of active HBV replication as demonstrated by the reappearance of serum hepatitis B surface antigen (HBsAg). In one patient, an HBsAg subtype difference indicated that the second period of HBsAg-positivity was due to a reinfection. In the other cases, reactivation may also explain the findings. All cases were anti-HIV-1 seropositive at the time of reappearance of HBsAg. There is experimental evidence that anti-HBc has a protective effect against HBV infection; however, this may require intact cell-mediated immunity to be effective. HIV-1 infection may render such patients susceptible to reinfection. Alternatively, some patients with anti-HBc, but without detectable anti-HBs may have latent HBV infection. Immunosuppression associated with HIV-1 infection may allow reactivation.
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PMID:Hepatitis B virus reactivation or reinfection associated with HIV-1 infection. 314 92

This study confirms the presence of detectable antibody-dependent cell-mediated cytotoxicity (ADCC) towards both HTLV-I- and HIV-1-infected cell lines, mediated by normal donor peripheral blood mononuclear cells and either by antibody from adult T-cell lymphoma and tropical spastic paraparesis patients (HTLV-I) or by antibody from sera of patients with persistent generalized lymphadenopathy, AIDS-related complex, AIDS and asymptomatic patients seropositive for HIV-1 infection. A comparison of ADCC towards these two retroviruses, under carefully controlled laboratory conditions, indicates major differences between the capacity of HTLV-I-seropositive sera and HIV-1-seropositive sera to mediate ADCC. In all cases, HIV sera showed low-titre ADCC, in contrast to the high titre (greater than 1:800,000) ADCC mediated by HTLV-I-positive sera. Both sets of sera showed the prozone phenomenon, and heat inactivation may abolish ADCC towards HIV-1-infected cells. Quantitation of surface antigen expression on HTLV-I- and HIV-1-infected cell lines indicated the presence of easily detectable amounts of virus-specific antigen. We conclude that, in contrast to some previous reports, ADCC mediated by HIV-1-specific immunoglobulin G (IgG) antibody is rather weak and of low titre when compared with HTLV-I ADCC. This is true for all cell lines and HIV-1 virus isolate combinations tested.
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PMID:Antibody-dependent cell-mediated cytotoxicity: comparison between HTLV-I and HIV-1 assays. 314 93

Serum samples taken from 6,624 blood donors since 1984 to 1987, were tested for Hepatitis B virus surface antigen (HBs Ag) using a microhemagglutination assay and for anti-HIV antibodies by ELISA test. The mean carrier state of HBs Ag was 10.68% and that of anti-HIV antibodies was 6.99%. The association of HBs Ag and anti-HIV antibodies was discovered in 4.84% donors but without correlation for the period of the study.
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PMID:[Carriers of HBs antigen, anti-HIV antibodies and their association with blood donors in Brazzaville]. 316 8

Recombinant adenoviruses were constructed that contained either the HBsAg coding sequence or the HIV envelope protein coding sequence. The recombinant adenoviruses can replicate normally in cultured human cells. Cells infected with the adenovirus-HBV recombinant secreted HBsAg into the tissue culture medium. This HBsAg had immunological and physical properties similar to those of the 22-nm particles found in human serum. Expression of HIV envelope protein in cells infected with the adenovirus-HIV recombinant was demonstrated using cytoimmunofluorescence and immunoprecipitation. A hamster model was developed to evaluate the immunogenic properties of adenovirus-HBV recombinants. Hamsters inoculated intranasally with live adenovirus-HBV recombinant produced antibody against both adenovirus and hepatitis B virus surface antigen.
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PMID:Expression of HBV surface antigen or HIV envelope protein using recombinant adenovirus vectors. 317 69

This article initially discusses the types of responses elicited by infectious agents, such as viruses and the role of each response in preventing, limiting, and clearing the infection. An important response is the generation of immunological memory, in both the B and T cell compartments. Generally, attenuated viral vaccines have been highly successful at inducing long-lived immunity but our understanding of the reasons for this comes from the study of model systems, such as murine influenza virus infections. Specific antibody may largely prevent infection and specific cytotoxic T cells and antibody-dependent cell cytotoxic reactions are the main mechanisms for clearing viral infections. Recent evidence shows that for some months after infection by HIV, a strong cytotoxic T (Tc) cell response occurs in infected, asymptomatic individuals; these cells are continuously generated by HIV-infected stimulator cells that most likely also serve as target cells in vivo. A low level of specific antibody is also formed and a number of reasons are listed to explain why HIV escapes antibody-mediated neutralization and infects cells expressing CD4 receptors. Cells of the macrophage/monocyte lineage are also infected and these express Fc and complement receptors; there is the strong possibility that infection of these cells occurred following the formation of complexes of infectious HIV with antibody to the surface antigen and attachment of complement components. The continuous presence of activated Tc cells that, in contrast to many other viral diseases, does not clear the infection strongly suggests that foci of infected cells sequestered from or resistant to immune control become established. These secrete virus that infects other (stimulator) cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prospects for HIV vaccines. 326 53

Dendritic cells (DC) are potent at presenting viral antigens in the initiation of both primary and secondary responses. DC in the lymph nodes draining the site of infection with HSV express surface antigen and can stimulate proliferation of sensitised lymphocytes. In secondary stimulation, nonresponsiveness in cytotoxic T cell assays of cells from mice primed to Moloney virus was also overcome by stimulation in vitro with virus-pulsed DC. Marked primary proliferative and cytotoxic T cell responses were previously found only to alloantigens and to haptens, both presented on the surface of DC However, DC exposed in vitro or in vivo to influenza virus stimulated primary proliferative and cytotoxic T cell responses in normal syngeneic lymphocytes in 20-microliters hanging drop cultures (Macatonia, Taylor, Knight and Askonas, in press). This provides a method for analysing primary responses to viruses in vitro without the necessity of using pre-sensitised donors. Although DC may present HIV antigens to lymphocytes the DC are also susceptible to infection with HIV. This occurs in vivo as evidenced by the infection of Langerhans cells in AIDS patients. This infection of DC may not only compromise their function in antigen presentation but also act as a reservoir of virus which is handed on to T cells during the close clustering of the presenting cells with the T cells during the initiation of the immune response.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Dendritic cells and viruses. 326 88

To evaluate the performance of a serological test for human immunodeficiency virus type 1 (HIV-1) infections based on the use of a recombinant envelope gene-derived protein as the antigen, we caused expression of a 1.4-kilobase fragment of HIV.DNA that codes for the complete gp41 transmembrane protein in an Escherichia coli expression vector and used Western blots (WB; immunoblots) prepared with recombinant material (pEX-41) to detect antibodies to HIV-1. This test detected all 339 sera which were positive by a combination of conventional serodiagnostic assays and produced no false-positive results with 311 negative samples. Also no false-positive results were obtained with 20 sera from systemic lupus erythematosus patients which had high titers of cross-reactive autoantibodies. In six cases, the pEX-41 WB proved to be more sensitive than individual assays applied on their own, and in five cases it was even more sensitive than a combination of conventional assays. We tested 221 sera in both our pEX-41 WB and a commercially available recombinant enzyme immunoassay (EIA [Abbott]). The results were identical in 188 cases. A total of 27 sera containing antibodies to gp41 as demonstrated in the pEX-41 WB, as well as the Abbott recombinant EIA, had no antibodies to the recombinant core antigen as measured in the Abbott EIA. However, 25 of these sera did stain the 24-kilodalton band on a WB with purified virus. Six sera that were positive in all of the conventional confirmatory assays and reacted strongly with the pEX-41 WB did not recognize the surface antigen used in the Abbott recombinant EIA. We conclude that the use of WB prepared with recombinant-derived p41 offers a very sensitive and specific method to detect antibodies to HIV.
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PMID:Comparison of Western blot (immunoblot) based on recombinant-derived p41 with conventional tests for serodiagnosis of human immunodeficiency virus infections. 327 88

The prevalence of hepatitis delta virus antibodies was determined in four cohorts of homosexual or bisexual men positive for hepatitis B surface antigen who were evaluated between April 1984 and April 1985. Antibodies to hepatitis delta virus were found in 16 of 106 men in Los Angeles (15.1%; 95% confidence interval [Cl], 8.3% to 21.9%); 6 of 64 men in San Francisco (9.4%; 95% Cl, 3.5% to 19.3%); 1 of 76 men in Pittsburgh (1.3%; 95% Cl, 0.03% to 7.1%); and 0 of 52 men in Chicago (0%; 95% Cl, 0% to 5.6%). From 44.0% to 65.4% of men negative for hepatitis delta virus and all men positive for hepatitis delta virus but one (P less than 0.0001) were positive for antibodies to human immunodeficiency virus (HIV). In multivariate analysis, infection with hepatitis delta virus was associated with intravenous drug use (adjusted odds ratio [OR] = 6.7, P less than 0.01), with sexual activity as measured by number of partners (adjusted OR = 8.4, p less than 0.01), and probably with rectal trauma (adjusted OR = 3.9, P = 0.17). As with HIV infection, prevalence of hepatitis delta virus infection in homosexual men differs by location and is most likely transmitted both sexually and parenterally.
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PMID:Human immunodeficiency virus and hepatitis delta virus in homosexual men. A study of four cohorts. 333 16

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.
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PMID:A high proportion of sera of heroin addicts possesses anti-HLA class I and class II reactivity. 333 95


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