Humoral and cellular aspects of immunoglobulin allotype suppression in the rabbit. IV. Kinetics of induction.

The injection of anti-b6 antibody into neonatal heterozygous b4b6 or b5b6 rabbits causes allotype suppression. Animals receiving a weight-related dose of antibody on day 2 or day 5 of life showed complete long-term chronic suppression of b6 immunoglobulin. Delay of injection until day 8, day 10 or day 11 of life resulted in more variable suppression, with animals showing either short- or long-term complete suppression or partial suppression. There was some correlation between levels of anti-b6 present in the circulation at day 21 and the degree of suppression obtained. Allotype suppression could be partially neutralized by injection of the paternal type immunoglobulin on days 19, 28, 30 or 43; if the injection was delayed until day 54, 66 or 79 there was no effect and chronic suppression proceeded as in control rabbits not receiving neutralizing immunoglobulin. The results indicate that the critical period for the induction of allotype suppression is between days 11 and 43 of life.