Abstract
Plaque-forming cell (PFC) responses to 2,4,6-trinitrophenylated lipopolysaccharide (TNP-LPS) were studied in normal and immunodeficient mice. In vivo immunizations with TNP-LPS showed a 25–50% reduction in PFC responses in CBA/N mice and their (CBA/N × BALB/c)F1(NBF1) male hybrids with an X-linked immune defect of B lymphocyte differentiation. A detailed clonal analysis of the reduced responses to TNP-LPS revealed that CBA/N and NBF1 male mice with the X-linked genetic defect have fewer precursor B cells engaged in the response to TNP-LPS than the control mice. The reduction in precursor cell numbers affects selectively B cells secreting high avidity anti-TNP antibodies as determined by PFC inhibition studies.