Summary
The antigenic multiplicity of the salmonella phage PB receptor sites has been established by neutralization reactions with anti-PB serum absorbed with coliphage T5 and with the heterologously reacting anti-T5 serum. The random distribution of the PB and T5-1ike antigenic structures on the phage receptor sites appears to contribute materially to the heterogeneity of a PB phage population with respect to neutralization by antiserum. The nature of these antigens is genetically controlled, and their spatial distribution in any phage particle appears to be a matter of chance.
It has been demonstrated that particles of a T5-PB phage hybrid which survive treatment with absorbed anti-T5 serum are inactivated by the absorbed anti-PB serum at the same rate as an untreated population. It appears that the resistant state is not acquired by spatial interference of antibodies attached to adjacent sites.
