Delineation of suppressor and helper activity within the OKT4-defined T lymphocyte subset in human newborns.
Lymphocytes taken from the cord blood of newborns have active suppressor activity. Using in vitro PWM-stimulated cocultures, unfractionated T cells from newborns potently suppressed the expected immunoglobulin G (IgG) synthesis of their mothers' peripheral blood lymphocytes (PBL). Using positive and negative selection techniques, we characterized the active suppressor cell as expressing the OKT4+T8- phenotype. This cord blood lymphocyte subset suppressed maternal IgG synthesis after depletion of maternal suppressor cells, implicating the ability of newborn T cells to suppress directly rather than by inducing adult suppressor activity. Sublethal amounts (1500 rad) of gamma-irradiation fully abrogated the suppressor activity of cord blood T lymphocytes. Radioresistant cord T cells provided T cell help. Irradiation of cord OKT4+ and OKT8+ populations and their subsequent culture with maternal B cells determined that helper activity was a radioresistant subpopulation of the OKT4+ subset. These results indicate significant differences in the functional properties of T cell subsets from adults and newborns. Population studies determined that cord blood lymphocytes had a greater proportion of OKT4+ cells and lower proportion of OKT8+ cells than PBL from unrelated adults. The mothers tested had similar proportions of OKT4+ cells as their babies, and these levels are significantly higher than those of unrelated adults.
D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D005260:Female; D005312:Fetal Blood / Q000166:cytology / Q000276:immunology; D006801:Humans; D007112:Immunity, Maternally-Acquired / Q000528:radiation effects; D007074:Immunoglobulin G / Q000096:biosynthesis; D007231:Infant, Newborn; D008213:Lymphocyte Activation / Q000528:radiation effects; D008211:Lymphocyte Cooperation / Q000528:radiation effects; D010641:Phenotype; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000528:radiation effects; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000502:physiology / Q000528:radiation effects
D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007074:Immunoglobulin G