Transformation of rabbit lymphocytes by anti-allotype serum: ultrastructure of transformed cells and suppression of responding cells by foetal exposure to anti-allotype serum.

The transformation of rabbit lymphocytes by anti-allotype serum (AAS) has been confirmed. The transformed cells closely resembled at the ultrastructural level those obtained by phytohaemagglutinin stimulation. The cytoplasm contained abundant free ribosomes with virtually no rough surfaced endoplasmic reticulum. A feature peculiar to AAS stimulated cultures was the presence of an amorphous material in and around the blast cells which might represent immune complexes of AAS with its antigen. The suppression of immunoglobulin allotype in animals heterozygous at a given locus by foetal exposure to AAS has been confirmed. It was further shown that this allotypic suppression was accompanied by gross deficiency in the number of peripheral blood lymphocytes which transformed in the presence of the AAS to which the animal had initially been exposed .