Evaluation of difficulties in the standardization of human and bovine tuberculins.

The tuberculins are made of mixtures of antigens. Certain elements are common to all tuberculins, others are particular to each one. Bovine and human tuberculins are widely different.

Search of a standard for the titration of antigen L.

The Antigen L is made of the 10 p.100 TCA precipitable proteins that remained after 2 p.100 TCA proteins precipitation of a live BCG culture filtrate.

[Antigen L, a new antigen from tubercle bacilli active in delayed hypersensitivity in animals sensitized with living bacilli (B.C.G.)].

This report described the occurrence of an antigen in the tubercle bacilli. The antigen, designated antigen L, was mainly active in delayed hypersensitivity reaction in Guinea Pigs sensitized with living bacilli such as the B.C.

[Comparative dose-effect relationship of a tuberculin standard on guinea pig sensitivity, using living and dead tuberculosis bacilli].

The sensitization of guinea pigs utilized for tuberculin titration may be obtained by a BCG primo-vaccination followed by an inoculation of live, virulent Myc. tuberculosis. This method, which results in a sub-evolutive form of tuberculosis, gives a satisfactory sensitization level but has the disadvantage of utilizing animals which are germ carriers and therefore dangerous.