Abstract
In experiments of serological neutralization of T2 bacteriophage, it was found that the rate of neutralization of the T2 by an immune rabbit serum depends upon the bacterium used for assay. However, the choice of host used in growing the phage stock has no effect.
Neutralization velocity constant of T2 assayed with each of four different cells, E. coli B, Shigella flexneri BIII, BI and KA, was about 200-380 min.-1, 430-520 min.-1, 620-730 min-1. and 800-900 min-1. respectively.
A possible inhibitory action of the anti-phage serum on the indicator cells was excluded by an experiment in which the antiserum was added to the agar layer of the assay plate.
These findings rules out the possibility that T2 phage stocks are composed of four different classes of monovalent phages each being able to invade only one of the four host cells. It would seem, rather, that each T2 particle has a complex antigenic structure in its site of attachment which is neutralized differently by the corresponding antibodies.
