title: Frequency of thymus-dependent plaque-forming units: direct estimation by a modified plaque assay.
mesh_terms: D000818:Animals; D003601:Cytotoxicity Tests, Immunologic; D006462:Hemolytic Plaque Technique; D007111:Immunity, Cellular; D007942:Leukemia, Experimental / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013601:T-Lymphocytes / Q000276:immunology*