Immune response to phosphorylcholine. VIII. The response CBA/N mice to PC-LPS

CBA/N mice and F1 crosses of CBA/N X BALB/c with the CBA/N phenotype respond to immunization with PC-LPS with a PC-specific and an anti-bridge antibody production. The PC-specific response in defective CBA/N and NBF1 is devoid of the IgG3 subclass and is not T15 idiotype dominant, whereas normal BALB/c and nondefective NBF1 mice express the T15 dominantly in their anti-PC-LPS response. By the criteria of responsiveness to PC-LPS only and the absence of dominant T15 expression, the precursors in defective NBF1 mice for TI-1 antigen PC-LPS can be characterized as being immature B cells similar to those found in neonatal livers of normal BALB/c or in spleens of chronically idiotype suppressed BALB/c mice. This analogy suggests that the developmental defect in CBA/N mice becomes active during the maturation process before selection for clonal dominance occurs and specialization of precursors for the preferred expression of the IgG3 subclass is completed. Alterations in the T cell compartment may contribute to the immature nature of B cells in the sex-linked immunodeficiency of CBA/N mice.