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Biomedical subjects

B Guy

Publications and source records attributed to B Guy.

44 records · Page 3Linked to original sources
PubMed1989

Human immunodeficiency virus-specific cytotoxic responses of seropositive individuals: distinct types of effector cells mediate killing of targets expressing gag and env proteins.

By using target cells that expressed isolated env, gag, p27nef, or p23vif molecules introduced by recombinant vaccinia viruses containing genes encoding these polypeptides, it was possible to identify env, gag, p27nef, and p23vif as cytolytic target antigens for freshly isolated blood cells from human immunodeficiency virus 1 (HIV-1) seropositive patients. Most of the patients tested (95%) manifested a specific cytotoxic activity against vaccinia virus-env-infected target cells. The env-specific cytotoxic activity was not restricted by the major histocompatibility complex and was not mediated by T lymphocytes, as shown by the absence of blocking effect with an anti-CD3 monoclonal antibody and by the inefficiency of CD3+, CD8+, or CD4+ and CD8+ depletion to reduce the cytotoxic activity against the env-expressing target cells. In the same conditions, the cytotoxic activity specific for gag was abrogated and gag major histocompatibility complex-restricted cytotoxic T lymphocytes were detected in 85% of the subjects tested. Therefore, in a HIV-1 seropositive subject, distinct types of effector cells mediate the lysis of target cells expressing gag and env proteins.

Antibodies, Monoclonal↗
PubMed1988

HIV-specific T lymphocyte immunity in mice immunized with a recombinant vaccinia virus.

Infection by the human immunodeficiency virus (HIV) induces T cell immunity in humans, chimpanzees and macaques. The protective value of this immune response is not clear. We have consequently developed a murine experimental system to study HIV-specific CD4 and CD8 T lymphocyte immunity in vitro and in vivo. BALB/c, DBA/2 and C3H/He mice were immunized with vaccinia virus (VV) recombinant VV-11.39 which expresses the gp160 glycoprotein of HIV-1. Primary and secondary cytotoxic T lymphocyte response to HIV were detected with histocompatible mouse target cells transfected with the HIV-1 env gene. Killer cells were positive for the Thy-1 and Ly-2 (CD8) T cell markers, and were restricted by class I H-2 histocompatibility antigens. Immunological memory specific for HIV-1 envelope antigens was clearly induced by vaccination with VV-11.39:spleen cells from mice vaccinated 4 weeks or more prior to assay generated CD4 and CD8 T lymphocyte responses following stimulation in vitro with HIV envelope antigens. The intensity of these responses increased with consecutive vaccinations, indicating that HIV-specific precursor T cell pools were progressively amplified. Finally, DBA/2 mice vaccinated with VV-11.39 developed protective immunity against a syngeneic tumor which expresses HIV-1 env antigens, leading to accelerated tumor rejection and increased survival.

Animals↗
PubMed1988

Isotypic restriction of the antibody response to human immunodeficiency virus.

HIV-infected individuals progress toward AIDS despite the early elicitation of a specific immune response. Analysis of the isotypic distribution of HIV-specific antibodies appears of special interest for two reasons: first, isotypic diversity is partly under the control of antigen-specific T-helper cells, the very cells infected by HIV; second, isotype determines antibody functions, effector (neutralization, antibody-dependent complement, or cell-mediated cytotoxicity) as well as blocking functions. We have investigated by Western blot analysis the isotypic profile of the antibody response to HIV structural proteins (env, gag, pol) and to the nonstructural protein F (3' orf), which is absent from the virion and might primarily target infected cells. In 115 asymptomatic individuals, infected by sexual contact (homosexual men) or intravenously (hemophiliacs), the response to gag-products was polyisotypic, including IgM, IgG1, IgG3 and IgA; the response to F was more restricted (IgM, IgG1, IgA) and the response to env strikingly restricted to the IgG1 isotype, suggesting different regulatory mechanisms in the B-cell response to these proteins. The isotypic distribution was also influenced by the route of infection, IgG4 and IgE (gag-specific) being exclusively elicited in the hemophiliac group. Finally, observations of potential diagnostic interest were made in a limited number of at-risk individuals; these included the presence of gag- and pol-specific IgM or IgA in the absence of any HIV-specific IgG isotypes; and the presence of gag- and F-specific antibodies in the absence of env-specific antibodies, suggesting the early occurrence of both isotypic and antigenic selection mechanisms during the course of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1968

[Thalassotherapy].

Explore the source record for details and available documents.

Climatotherapy↗
PubMedDate not supplied

HIV F/3' orf encodes a phosphorylated GTP-binding protein resembling an oncogene product.

Apart from the retroviral gag, pol and env the HIV genome contains the F (3' orf) gene which encodes a polypeptide of 206 amino acids which is myristylated at the N-terminal and whose function is unknown. We have expressed the F gene in Escherichia coli and from a recombinant vaccinia virus, VVTGfHIV. The F-protein produced in VVTGfHIV-infected mammalian cells is myristilated, and is phosphorylated by protein kinase C at a residue close to the N-terminus like pp60-src (ref. 5). Purified bacterial F-protein also shows the GTPase, autophosphorylation and GTP-binding activities reported for the ras gene product. Furthermore, we show that expression of F in a CD4+ cell line down-regulates the CD4(T4) antigen. These results suggest that F is important in the pathophysiology of AIDS (acquired immune deficiency syndrome).

Antigens, Differentiation, T-Lymphocyte↗