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F Plata

Publications and source records attributed to F Plata.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Immune resistance to Trypanosoma cruzi: synergy of specific antibodies and recombinant interferon gamma in vivo.

The protective effects of interferon gamma (IFN-gamma) against infection by Trypanosoma cruzi were studied in vitro and in vivo in a murine model of infection. The possible synergy between IFN-gamma and trypomastigote-specific antibodies in the rejection of the parasite was also considered. Our results in vitro indicate that IFN-gamma activates macrophages to reject the parasite and this mechanism may lead to a decrease in parasitaemia in vivo. Finally, IFN production in vivo after infection by T. cruzi was compared among mice from different genetic backgrounds. Reduced parasitaemia and extended survival correlated with the early production of circulating IFN-gamma and anti-trypomastigote antibodies after infection. The appearance of an unusual type of circulating IFN in response to infection by T. cruzi was also detected; this IFN was resistant to neutralization by antibodies to IFN-alpha/beta and to IFN-gamma.

Animals↗
PubMedDate not supplied

AIDS virus-specific cytotoxic T lymphocytes in lung disorders.

Human immunodeficiency virus (HIV) is implicated in the development of AIDS (acquired immune deficiency syndrome). HIV infection leads to the generation of HIV-specific thymus-derived (T) lymphocytes in humans and apes. We describe an experimental system permitting the quantitative and systematic analysis of HIV-specific cytotoxic T lymphocytes (CTL). Functional, HIV-specific CTL are obtained by broncho-alveolar lavage (BAL) from the lungs of seropositive patients with lymphocytic alveolitis. These alveolar CTL: (1) recognize and kill HIV-infected alveolar macrophages in vitro under autologous, but not heterologous, conditions; (2) correspond to standard CTL as they express the CD3 and CD8 surface markers, but not the CD4 marker; and (3) are restricted by class I HLA transplantation antigens in their cytotoxic activities. We propose the hypothesis that interactions between HIV-specific CTL and infected macrophages induce major inflammatory reactions in seropositive patients.

Cytotoxicity, Immunologic↗
PubMedDate not supplied

Molecular definition of retrovirus-induced antigens recognized by tumour-specific H-2-restricted cytolytic T lymphocytes.

The antigenic specificities of H-2-restricted, tumour-specific cytolytic T lymphocytes (CTL) were studied at the molecular level using CTL from BALB.B and C57BL/6 (H-2b) mice sensitized to an H-2b Gross murine leukaemia virus (MuLV)-induced tumour. Target cells were produced by the double transfection of mouse L cells (H-2k) with the cloned H-2Kb or H-2Db gene and retroviral DNA derived from a molecular clone of Akv MuLV (closely related to Gross MuLV). Doubly transfected L cells which express either H-2Kb or H-2Db antigen and retroviral antigens are lysed in a virus-specific manner by Gross MuLV-immune CTL. The existence of two independent Gross MuLV-immune CTL subpopulations, one restricted by H-2Kb and the other by H-2Db, is thus confirmed. Gross MuLV-immune CTL from both BALB.B and C57BL/6 mice killed L cells that express Akv MuLV gag gene products and H-2Kb or H-2Db antigen. In contrast, only CTL from C57BL/6 mice killed L cells that express Akv MuLV env gene products and H-2Kb or H-2Db. This indicates that specific recognition of MuLV-induced antigens by CTL can be selective and varies according to the origin of the CTL.

AKR murine leukemia virus↗
PubMedDate not supplied

Selective suppression of tumour-immune cytolytic T lymphocytes in mice with chronic Trypanosoma cruzi infections.

Trypanosoma cruzi is the causative agent of Chagas' disease in man, often leading to suppression of T lymphocyte functions; the present study thus considered the effects of infection by T. cruzi on T-dependent immune responses in a murine model, namely, the immune resistance to a syngeneic tumour and a delayed-type hypersensitivity reaction to sheep red blood cells (SRBC). In BALB.B mice infected with T. cruzi, the graft of syngeneic Gross murine leukaemia virus-induced tumour cells leads to an increased incidence of progressive subcutaneous tumours and development of lymphatic leukaemia. This decreased resistance to tumours correlates with a suppression of the generation of tumour-specific cytolytic T lymphocytes (CTL) from the pre-CTL stage. In contrast, clonal expansion and circulation of T cells detected through their ability to locally transfer a delayed-type hypersensitivity (DTH) reaction to SRBC remained normal in T. cruzi-infected mice. However, at the site of the DTH reaction, a decreased availability of phagocytes was observed in T. cruzi-infected mice.

Animals↗