Abstract
For the purpose of biological potency test on lepromin, particularly on the Dharmendra antigen, guinea pigs were sensitized with defatted leprosy bacilli suspended in liquid paraffine, and various conditions necessary for the optimal sensitization as well as the specificity of cutaneous reactions were examined, comparing with those in animals sensitized with heat-killed tubercle bacilli.
It was found that the sensitization of guinea pigs to defatted leprosy bacilli is achieved by the injection of about 10 times larger amount of the bacilli and after longer period of incubation than the sensitization with dead tubercle bacilli. However, the cutaneous reaction in guinea pigs sensitized with the former was relatively specific to the Dharmendra antigen.
Adjuvant effect of lipid fractions extracted from leprosy nodules on the sensitizing as well as cutaneous reactivity of defatted leprosy bacilli was also examined, and it was found that the alcohol-insoluble fraction has an intensifying effect on the protency of the Dharmendra antigen, in contrast to the inhibitory action of the alcohol-soluble one. However, skin-sensitizing activity of defatted leprosy bacilli was not influenced by the addition of acetone-insoluble lipid which composed of the above two fractions, because of contradictory effect of each other.
