COLONY-FORMING B CELLS IN F-1 HYBRID AND TRANSPLANTED CBA-N MICE

B lymphocytes which form colonies in semisolid cultures were assayed in the F1 progeny of mutant CBA/N and wild-type CBA/H mice. Male offspring of CBA/N mothers had no clonable B cells, and their heterozygous female litter-mates had approximately half the incidence and total number of colony-forming cells found in age-matched normal CBA/H females. Normal and defective mice were lethally irradiated and grafted with hemopoietic cells from either normal or CBA/N mice. Recipients of CBA/N cells did not regenerate B cells which function in the cloning assay, whereas colony-forming cells returned to a normal incidence in all mice grafted with normal cells. Cytogenetic analysis confirmed that the clonable B cells in reconstituted CBA/N mice were derived from donor CBA/H-T6T6 cells. Newborn CBA/N mice had normal numbers of immunoglobulin-bearing cells, and these subsequently acquired Ia antigens. However, these B cells did not expand to the numbers found in the spleens of normal adult mice. These findings confirm and extend earlier studies of immunodeficient CBA/N mice and suggest that a mutation of a single X-chromosome-borne gene affects the production and/or functional capability of at least one category of virgin B lymphocytes. © 1978.