title: Human cord blood suppressor T lymphocytes: I. Phenotype and target of the inducer of suppressor cell factor.
abstract: The present study examines the characteristics of the cord suppressor T cells and their targets. When an inducer of suppressor T cell factor (TisF) from culture supernatant of alloantigen-activated cord lymphocytes was used as a source of suppression, adult lymphocyte response to soluble antigen candidin, alloantigens, and pokeweed mitogen were all suppressed. These results suggest that TisF acts primarily on T cells in an antigen-nonspecific fashion. Furthermore, preculture T cell irradiation, but not T8+ cell depletion, of adult lymphocytes abrogated the suppressive effect of TisF on the PWM-stimulated IgG production, suggesting that the target of TisF belongs to the radiosensitive T8-(T4+) T cell subset. When different cord T cell subsets were tested for suppressor activity, only radiosensitive T4+ cells were capable of suppressing IgG production by adult lymphocytes. Neither preculture T8+ cell depletion nor irradiation of adult T cells affected the suppression. Taken together, these results suggest that the suppressor activity of cord T cells originated from an inducer of suppressor cells that activates radiosensitive T4+ suppressor effector cells through TisF. In turn, these effector cells act on either radioresistant T4+ helper T cells or B cells or both.
authors.forename: H
authors.initials: H
authors.lastname: Cheng
authors.forename: A H
authors.initials: AH
authors.lastname: Sehon
authors.forename: G
authors.initials: G
authors.lastname: Delespesse
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D004261:DNA Replication; D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D008213:Lymphocyte Activation; D010641:Phenotype; D011247:Pregnancy; D011863:Radioimmunoassay; D013491:Suppressor Factors, Immunologic / Q000032:analysis* / Q000502:physiology; D013601:T-Lymphocytes / Q000145:classification; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D013491:Suppressor Factors, Immunologic