B lymphocyte development and activation independent of MHC class II expression.
A murine model of MHC class II deficiency created by targeted gene disruption was used to investigate whether class II expression influences B cell maturation and function. There appeared to be fewer total B cell precursors, a higher proportion of which were in a very early stage of maturation, in class II-deficient vs control bone marrow; however, the differences did not reach statistical significance. Mature B cells were unaffected; IgM, IgD, B220, and CD5 surface expression were similar in class II-deficient and control animals. Serum Ig determinations revealed that the class II-deficient animals had elevated IgM but decreased IgG1 (and, variably, IgE) compared to control. The antibody response against thymic-independent Ag was intact in class II-animals, as was the in vitro response of small resting B cells from class II deficient animals to stimulation with polyclonal B cell activators. Preactivated T cells were able to induce differentiation and proliferation of class II-deficient, small resting B cells. Together, these data indicate that B cell development, T cell-independent, and T cell-dependent B-cell activation, can occur independently of class II MHC expression.
Markowitz
J S
JS
Department of Cancer Biology, Harvard School of Public Health, Boston, MA 02115.
Rogers
P R
PR
Grusby
M J
MJ
Parker
D C
DC
Glimcher
L H
LH
D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology; D002454:Cell Differentiation; D005434:Flow Cytometry; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D051379:Mice; D016254:Mutagenesis, Insertional; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D013601:T-Lymphocytes / Q000276:immunology
D000949:Histocompatibility Antigens Class II; D011947:Receptors, Antigen, B-Cell