Specificity of mycobacterial sensitins.

The influence of various inoculation routes on the development and specificity of mycobacterial hypersensitivity reactions was investigated. The results indicated that the rate of development of skin test reactions was not determined by the inoculation route. Skin test reactions were seen within two hours after antigen injection and were often highly developed within 8-10 hours. The reactions were characterized by maximum appearance of inflammation at 24-30 hours followed by a decline in size beginning at 48 and 72 hours. Latex agglutination tests carried out with guinea pig sera 3 weeks after sensitization indicated the presence of circulating antibody at the time skin tests were performed. The sensitivity patterns induced by M. kansasii and M. tuberculosis, strain H37Ra induced responses in the order of PPD-S greater than PPD-Y greater than PPD-A. M. kansasii induced responses in the order of PPD-Y greater than PPD A greater than PPD-S. Cell extracts M. kansasii obtained by freezing-thawing and ultrasonic disruption was subjected to polyacrylamide (disc) electrophoresis. At least 10 bands could be distinguished and 4 major bancs were separated. Chemical analysis of the material eluted from the 4 major bands indicated that skin test activity was correlated with polysaccharide in association with protein. Skin test bio-assay data were analyzed by computer analysis. Values for parallelism of the log-dose response curve for the unknown and standard indicated that one band (K-3) contained active material of similar chemical constitution of that of PPD-Y. Another band (K-4), although active, exhibited non-parallelism suggesting the presence of other or different active material. Material isolated from the cell extract of M. kansasii by disc electrophoresis was not more specific than presently available PPD-Y. However, the studies indicated that the band fractions met the definition of "sensitin" in that the agents were capable of detecting delayed hypersensitivity without inducting the production of antibody.