title: Immunoregulatory T cells in measles. The relationship between reduced lymphocyte proliferative response to PHA and increased proportion of circulating suppressor-cytotoxic T cells.
abstract: Viral infections are often associated with immunodeficiency states. Although T lymphocytes have been thought to suppress the host's immune response, the precise cellular basis for this phenomenon remains unclear. Therefore, we characterized peripheral blood mononuclear cells from 9 measles virus-infected children by means of monoclonal antibodies directed against surface antigens expressed on human T lymphocytes and T-cell subsets. In addition, the measles lymphocyte blast transformation response to the T-cell mitogen phytohaemagglutinin (PHA) was evaluated as an index of specific T-cell immunocompetence. During the course of measles, there was a slight reduction in the proportion of total circulating T cells, with a relative decrease in helper-inducer and a parallel increase in suppressor-cytotoxic T lymphocytes. The PHA lymphocyte blastogenic response was found to be defective in children with measles and, interestingly, there was a significant negative correlation between the reduced PHA blast transformation value and the increased proportion of suppressor-cytotoxic cells. The biological implications of these finding with respect to the underlying immunopathology of the measles virus infection are discussed.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000954:Antigens, Surface / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D008297:Male; D008457:Measles / Q000276:immunology*; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000145:classification / Q000166:cytology; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D010835:Phytohemagglutinins