[Serological characterization of bacteriophage T3 carrying different "non-classical" modifications].

The antigenic properties of bacteriophage T3 and a mutant T3/R7 which undergoes "non-classical" modification and restriction are compared. The "non-classical" modification of T3/R7 consists of a host-dependent, reversible change in the adsorption capacity of phage on different host strains. We have shown that this modification is connected with changes in the antigenic properties of phage components involved in phage absorption to the host cell. This means that, in contrast to the "classical" host-control-led modification and restriction of DNA, the "non-classical" modification and restriction of phage is based on protein modification.