title: Regulation of the anti-alpha (1,3) dextran response: two populations of dextran-reactive B cells that differ in their T cell requirements for induction to antibody synthesis.
abstract: The in vitro antibody response to dextran B1355S, a thymus-independent Type 2 antigen, requires T cell-derived lymphokines but is not thought to require an activation signal from an antigen-specific T helper cell. The present study demonstrates that there are two dextran-reactive B cell populations in BALB/c mice with respect to the T cell requirements for the generation of antibody-forming cells. One population found among dextran-reactive spleen B cells from 12- to 14-mo-old BALB/c mice generated anti-dextran PFC in the presence of B cell growth factor (BCGF II) and IL 2 or the combination of BCGF II, IL 2, and IFN-gamma. A second population of dextran-reactive B cells found in spleen and Peyer's patches of 2-mo-old unprimed mice did not respond to these same lymphokines, but did generate anti-dextran plaque-forming cells in the presence of Thy-1.2+, L3T4+ T cells from Peyer's patches. However, splenic B cells obtained from 2-mo-old mice that had been primed with dextran 2 to 3 days after birth were shown to be responsive to the same lymphokines as dextran-reactive B cells from 12- to 14-mo-old mice. These results suggest that previous priming with dextran B1355S induces a dextran-specific B cell population that can be activated to antibody-forming cells in the presence of antigen and T cell-derived lymphokines, whereas a second, unprimed population requires an additional activation signal from L3T4+ T cells.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000145:classification / Q000187:drug effects / Q000276:immunology*; D003911:Dextrans / Q000276:immunology*; D006133:Growth Substances / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology; D015847:Interleukin-4; D008211:Lymphocyte Cooperation; D008222:Lymphokines / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C / Q000276:immunology; D010581:Peyer's Patches / Q000166:cytology; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D003911:Dextrans; D006133:Growth Substances; D007376:Interleukin-2; D008222:Lymphokines; D015847:Interleukin-4; D007371:Interferon-gamma