Journal of Experimental Medicine, Vol 147, 1374-1394,
Copyright © 1978 by Rockefeller University Press
the relationship between surface immunoglobulin isotype and immune function of murine B lymphocytes. III. Expression of a single predominant isotype on primed and unprimed B cells
I Zan-Bar,
ES Vitetta,
F Assisi,
and
S Strober
We determined whether primed and unprimed B cells in the spleen of (BALB/c × C57BL/Ka)F(1) mice contain subpopulations that express a predominant surface Ig isotype. Spleen cells were stained for surface isotypes and sorted on the fluorescence-activated cell sorter (FACS) in order to obtain B cells bearing predominantly IgM (
p cells), IgD (
p cells), or IgG (
p cells). Each population was assayed for its capacity to restore the adoptive primary and secondary anti-bovine serum albumin (BSA) antibody response in irradiated syngeneic recipients. In addition, the adoptive response restored by isotype-predominant cells was compared to that restored by isotype- positive cells (B cells bearing a given surface isotype alone or in combination with others). The experimental results show that
p cells restore the adoptive primary and secondary IgM and IgG responses to BSA, and
P cells restore only the primary and secondary IgG response.
p Cells restored the adoptive secondary IgG response, but failed to restore the adoptive primary response at the cell doses tested.
P Cells but not
p cells suppressed the IgM response of the
(+) and
(+) cells. The contribution of isotype-predominant cells to both the adoptive primary and secondary anti-BSA response was smaller than that of B cells bearing a combination of surface isotypes. Differences in the Ig isotype pattern expressed on the surface of primed and unprimed B cells are discussed.