Expression of a distinct B cell clonotype profile after recovery from antigen-induced unresponsiveness.

The purpose of these experiments was to determine whether the B cell clonotype profile expressed in mice which have recovered from antigen-induced unresponsiveness is similar to that of nontolerized mice. Unresponsiveness to phosphorylcholine (PC) was initiated by injection of neonatal mice with PC-coupled human gamma globulin, resulting in the inability to respond to challenge with PC-lipopolysaccharide at 1.5 months of age. By 3 months of age, pretreated mice were 50% responsive while by 5 and 7.5 months of age, full responsiveness was observed. At each time point two differences distinguished the anti-PC antibody from nonpretreated mice. First, whereas nonpretreated mice displayed T15 dominance, pretreated mice did not. Second, the average avidity of T15-negative antibody produced in pretreated mice was greater than that in nonpretreated mice and similar to that of T15-positive antibody. Possible mechanisms for this "permanent" alteration of the antibody profile are discussed.