RESUMO
The purpose of the work here reported was to determine whether or not the Mitsuda reaction can be produced by leproma emulsions in which the bacillary elements have been destroyed, at least to the point of loss of acid-fastness, by application of ultra-supersonic waves. Vaccines so prepared, it has been found, retain antigenic capacity, though it is much weakened. They are similar to the standard Mitsuda antigen in that they fail to cause positive reactions in lepromatous cases, while neural-type cases and healthy persons react positively. The quality of the U-vaccine is not affected by heating. In view of the fact that all of the components of the bacilli remain in the U-vaccine, the weakening of the reaction indicates that it depends upon the presence of the formed leprosy bacilli themselves. This is further indicated by the fact that a filtrate of the U-vaccine is incapable of producing positive reactions, though it must contain all of the soluble bacterial substances. On the other hand, it is also a fact that the small numbers of bacilli present in the U-vaccine can, in some healthy persons and maculo-neural cases, cause reactions approximately as strong as those induced by the Mitsuda antigen itself. The fact that few bacilli can cause strong reactions has already been proved with diluted Mitsuda vaccine in cases of "akuter Schub". The same results have been obtained with the U-vaccine containing small numbers of bacilli that are losing their acid-fastness. Why can the U-vaccine cause the Mitsuda reaction, despite the fact that it may contain nothing which can be stained by methylene blue or by the Ziehl-Neelsen method? It is a fact that this preparation is turbid, though of course much less so than the original Mitsuda vaccine. Yhis turbidity is due to a mass of fine bacillary particles that are not acid-fast. These particles still retain the capability of causing the Mitsuda reaction, though of much weakened grade. This agrees with Hayashi's findings with leprosy bacilli treated with hydrochloric acid. The fact that, contrary to our expectations, the filtrate of this vaccine does not cause the same reaction as the unfiltered substance is further evidence of the essential nature of the Mitsuda reaction. Comparing this filtrate and one of the Mitsuda vaccine, the former, in the first several days, caused stronger reactions than the latter in healthy and neural persons,...