STUDIES ON THE LEPROMIN TEST(THE FIFTH REPORT)

POTENCY TEST OF THE LEPROMIN ANTIGEN USING GUINEA PIGS SENSITIZED WITH TUBERCLE BACILLI

Abstract

As reported in the fourth report of this series of experiment, it was found that guinea pigs can not be sensitized to lepromin with leprosy bacilli, but sensitized to both lepromin and tuberculin by the injection with tubercle bacilli. Therefore, using guinea pigs sensitized with heat-killed tubercle bacilli suspended in paraffin oil, the authors analyzed the relation between size of skin reaction and antigen dilution, comparing both cases of tuberculin and lepromin. The results were summarized as follows.
Both the Mitsuda and Dharmendra antigens showed a good proportional relation between antigen dilution and size of skin reaction, particularly the Dharmendra antigen did sq even in a very limited range of dilution such as 1: 1 to 1:2.25, when reading was made in 24 hours after the antigen injection.
Next, several samples of the Mitsuda and Dharmendra antigens were examined of their relative antigenic potency, taking one of them as an antigen of the temporary standard potency, and expressed in the term of ratio (size of reaction due to test sample/size of reaction caused by the standard). Considerable differences were noticed among the potency of these samples. In addition, the yield of the Dharmendra antigen was found to vary greatly according to leprous nodules used as the starting material.