[Possible existence of autoantibodies against immunoglobulin allotypes in normal rabbits, and their relation to the expression of these allotypes].

The concentration of a3 allotype was increased in the serum of heterozygous a1 a3 rabbits which received antiidiotypic antibodies against anti-a3 antibodies in the perinatal period. This is explained by the normal presence of anti-a3 autoantibodies which control the expression of a3 allotype in heterozygous a1 a3 rabbits under physiological conditions.