title: Enumeration of activated thymus-derived lymphocytes by the virus plaque assay.
abstract: Lymphocytes activated by antigens or mitogens acquire the capacity to replicate viruses, and the number of activated lymphocytes can be estimated by the virus plaque assay. Concanavalin A and pokeweed mitogen produced 33-fold and 17-fold increases in virus plaqueforming cells (V-PFC), respectively, above background, while lipopolysaccharide produced only a 2- to 3-fold increase. T (thymus-derived lymphocyte)-depleted lymphocyte populations, derived from anti-theta-treated or nude (arthymic) mouse spleens, failed to produce V-PFC after culture with concanavalin A or pokeweed mitogen. The present studies thus demonstrate that the virus plaque assay measures activated T-lymphocytes.A dissociation between the V-PFC response and cell proliferation was previously observed in antigen-stimulated cells cultured in the presence of mitotic inhibitors. In the present studies, while stimulation of CBA (H2(k)) lymphocytes by DBA/2 (H2(d)) cells produced high levels of thymidine incorporation, lymphocyte target-cell cytotoxicity, and V-PFC, stimulation of BALB/c (H2(d)) lymphocytes against DBA/2 (H2(d)) cells resulted in even higher levels of thymidine incorporation with a virtual absence of cytotoxic lymphocytes or V-PFC. These results indicate that proliferation is not a sufficient condition for permitting lymphocytes either to exert cytotoxicity on target cells or to replicate viruses, and suggest that there may be a correlation between the development of V-PFC and cytotoxic lymphocytes. They are consistent with the view that there are at least two functional subpopulations of T-lymphocytes.
mesh_terms: D000818:Animals; D000941:Antigens; D000961:Antilymphocyte Serum / Q000494:pharmacology; D003208:Concanavalin A / Q000494:pharmacology; D003601:Cytotoxicity Tests, Immunologic; D004247:DNA / Q000096:biosynthesis; D005260:Female; D008070:Lipopolysaccharides; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D013601:T-Lymphocytes / Q000276:immunology*; D013936:Thymidine / Q000378:metabolism; D014316:Tritium; D014721:Vesicular stomatitis Indiana virus / Q000254:growth & development; D010948:Viral Plaque Assay; D014779:Virus Replication
chemical_list: D000941:Antigens; D000961:Antilymphocyte Serum; D008070:Lipopolysaccharides; D014316:Tritium; D003208:Concanavalin A; D004247:DNA; D013936:Thymidine