Capacity of small B cell-enriched populations to stimulate mixed lymphocyte reactions: marked differences between irradiated vs. mitomycin C-treated stimulators.
To investigate whether small B cells can stimulate mixed lymphocyte reactions (MLR), highly purified populations of large vs. small B cell fractions were tested for their capacity to evoke MLR across Mls vs. H-2 barriers. Large B cell fractions stimulated high MLR to Mls and H-2 determinants, irrespective of whether the stimulators were exposed to irradiation or pretreated with mitomycin C. In accord with the findings of others, irradiated small B cell fractions proved to be very poor stimulators of MLR. Significantly, however, mitomycin C-treated small B cell fractions elicited high MLR, particularly to Mls determinants. The finding that small B cell fractions treated with irradiation are poor stimulators of T cells correlates with the known radiosensitivity of B cells. In this respect, the widely held view that small B cells do not have antigen-presenting cell (APC) function rests largely on studies with irradiated B cells. The present finding that T cells respond well to small B cells treated with mitomycin C, however, indicates that small B cell fractions do have APC function. Whether the APC function of small B cells reflects a response to resting B cells per se rather than to cells undergoing activation in vitro, however, remains to be ascertained.
Webb
S R
SR
Li
J H
JH
Wilson
D B
DB
Sprent
J
J
D000818:Animals; D001402:B-Lymphocytes / Q000145:classification* / Q000187:drug effects / Q000528:radiation effects; D006183:H-2 Antigens / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000528:radiation effects; D007959:Lymphocyte Culture Test, Mixed / Q000379:methods*; D051379:Mice; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D008912:Minor Histocompatibility Loci; D008937:Mitomycins / Q000494:pharmacology*
D006183:H-2 Antigens; D008937:Mitomycins