An examination of the TRF assay reveals a heterogeneity of TRF-like activities.
Supernatant from the cloned Mlsa,d-reactive helper T cell line L2V is a potent source of T cell replacing factor (TRF) activity. To determine whether L2V SF was representative of TRF-active supernatants, it was compared with supernatant from Con A-stimulated spleen cells (CASF) by using TRF assays. This analysis, facilitated by the use of four different antigens (R36a, TNP-R36a, SRBC, and HRBC), produced the following results. 1) L2V SF and CASF allowed responses of similar magnitude against either R36a or TNP-R36a; however, CASF always allowed responses of fivefold to 30-fold greater magnitude against SRBC than L2V SF. 2) B cells from xid and "normal" mice will give equally large responses to TNP-R36a when CASF is used as the source of TRF; however, L2V SF will only effect the responses by "normal" B cells. 3) L2V SF-driven responses to R36a and SRBC, and CASF-driven responses to R36a, follow single-hit kinetics and are IL 2 independent, whereas CASF-driven responses to SRBC follow multi-hit kinetics and are IL 2 dependent. These results indicate that the TRF assay measures a heterogeneity of TRF-like activities that can be distinguished according to the supernatant, antigen, and/or B cell responders used. The determination of whether this heterogeneity is due to the number of molecular components of a single "type" of TRF required for each antigen-induced PFC response or to the existence of distinct "types" of TRF is examined.
D000042:Absorption; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D003208:Concanavalin A / Q000494:pharmacology; D004306:Dose-Response Relationship, Immunologic; D006462:Hemolytic Plaque Technique; D015848:Interleukin-5; D007700:Kinetics; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000032:analysis*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism
D015848:Interleukin-5; D008222:Lymphokines; C021649:concanavalin A-induced helper factors; D003208:Concanavalin A