Charles C. Shepard

The preparation of antigens from yolk sacs infected with rickettsiae.

The preparation of antigens from the yolk sacs of eggs infected with the rickettsial agents has proved somewhat difficult. Use by Craigie (1) of diethyl ether as a lipoid solvent as well as a means of selectively removing tissue impurities was a definite advance in the preparation of rickettsial antigens from infected yolk sacs. The demonstration of a soluble antigen released from Rickettsia prowazeki when exposed to diethyl ether by Topping and Shear (2) added an active fraction that could be extracted from ether-processed yolk sacs. However, it has been found that no single procedure is applicable to all of the various rickettsial agents, therefore several modifications of the original techniques are necessary when working with different agents. For example, a soluble antigen is released by diethyl ether from both murine and epidemic typhus and from Rocky Mountain spotted fever but not from the rickettsiae of Q fever. The usual ether-extraction method fails to release a soluble antigen from both Q fever and tsutsugamushi rickettsiae, yet the method used for the preparation of Q fever antigens is not applicable to tsutsugamushi. It is the purpose of this paper to outline briefly three basic methods for the preparation of rickettsial antigens and to present the results of the three methods when applied to five of the rickettsiae.

Comparison of B1912 and Clofazimine (B663) in Mycobacterium leprae Infections

Summary The effect of clofazimine was compared with another, more newly developed rimino-compound, B1912, in M. leprae infections in mice. The two drugs were found to have very similar activity.

Discontinuous Administration of Clofazimine (B663) in Mycobacterium leprae Infections

Summary The prophylactic and spaced administration of clofazimine was studied. The drug had an effect when given orally for 2 days immediately after infection, but had no effect when given 5 weeks before infection. When given once every 4 weeks from Day 70 to Day 140 after infection, the drug had a distinct effect. It was also active when injected intraperitoneally on the day of infection.