Purified protoplasmic peptides of mycobacteria: isolation of species-specific peptides from protoplasm of mycobacteria.

Infections with mycobacteria other than tubercle bacilli are responsible for a variable percentage of cross-reactions to tuberculin. Two major suggestions for circumventing this problem have been made: the first, development of a quantitative tuberculin test, is based on the fact that most cross-reactions are smaller than those caused by true tuberculous infections; the second, preparation of purified skin test antigens from other mycobacteria, is based on the hope that greater specificity will be displayed by homologous sensitin. Effort so far has been focused on the culture filtrates as the source of antigen. This article describes the preparation of low molecular weight purified protoplasmic peptides (PPP) of specificity and sensitivity superior to purified protein derivatives.