Abstract
Rabbits were immunized with F1, F2, and F3, respectively and the precipitin titers and K-values were tested with reference to the protein amounts used. Results obtained were summarized as follows :
1) The lethal effect was seen in P22 protein, F1 and F2, i.e., rabbits died with subcutaneous injection of 0.09-1.8mg of them. On the other hand, the necessary doses of the protein preparations to obtain sufficient titers of antibodies ranged from 0.8mg to 2.0mg.
The preparations were injected subcutaneously in 4-5 times and dosis per injection was 0.3mg or 0.4mg. With these doses, some of the animals died after 1 or 2 injections.
2) Among the three fractions, only F3 was the fraction markedly relating to the production of the neutralizing antibody.
3) Precipitin was produced equally in animals injected with any of the three fractions, but with the equal amount of antigen, it was most marked with F1 and was followed by F2 and F3.
4) The neutralizing antibody was produced, also, with F2, but the titer was low and disappeared in a short period of time.
