FIG. 2.

Skin test reactivity of multiantigen cocktails in guinea pigs immunized with M. bovis BCG (solid symbols) and with M. avium (open symbols). Six guinea pigs were sensitized and skin tested as described in Materials and Methods. In this set of experiments, animals were skin tested with 10 TU of PPD and increasing amounts (0.5 to 8 μg) of multiantigen cocktails. Results are expressed as means of the diameters of erythema measured 24 h after antigen injection. Cocktail A, four M. tuberculosis complex-specific antigens (MPT63, MPT64, MTC28, and MPT70); cocktail B, four cross-reactive antigens (MPT51, Ag85B, MPT32, and KatG); cocktail C, eight-antigen cocktail (antigens in cocktails A plus B). ■, □, M. bovis PPD; ▴, ▵, M. avium PPD; •, ○, cocktails of purified antigens.