Human T Lymphocyte Recognition of Cyanogen Bromide Fragments of the Surface Protein of Rickettsia Typhi.

摘要

Rickettsiae preferentially invade and grow in endothelial cells of blood vessels in vivo.1 Rickettsia typhi and R. prowazekii induce humoral and cell-mediated immune responses, although the role played in the clearance of the organisms by each of these responses is still unclear. Despite the fact that rickettsial infection induces a vigorous antibody response, passive transfer of antibodies from immune animals to naive animals is not completely protective. Since rickettsia grow intracellularly, the organism is not generally accessible to the antibody. Antibody may play a role, however, in the clearance of rickettsiae from the host by facilitating phagocytosis by macrophages or polymorphonuclear leukocytes. Unlike antibody, the passive transfer of immune T lymphocytes to a naive recipient gives good protection against challenge by live rickettsiae. Since rickettsia-infected cells, like virus-infected cells, may express antigens of the infecting organism on their surface, it is possible these antigens play a significant role in the immune response to rickettsiae. Carl et al. demonstrated, in humans, that R. typhi- and R. prowazekii-immune T lymphocytes were specifically cytotoxic in a class II-restricted fashion. This strongly suggests that cytotoxic T lymphocytes (CTL) do have a role in anti-rickettsial immunity. Lysis of rickettsia-infected cells may, however, make the bacteria more susceptible to the opsonizing effect of antibody. Keywords: Reprints. (js)