The Immunological Response to Antigens of Mycobacterium Tuberculosis in the Guinea-Pig

Abstract

Results of an experiment in which guinea pigs were injected with antigens of M. tuberculosis in various forms (tuberculoprotein, living bacilli etc.). Subsequently blood was taken and serum antibodies were estimated by hemagglutination and hemolysis techniques. The animals were also skin tested with tuberculin and the details of the reactions were noted at intervals after the skin injection for 3 days. The best antibody response was in animals injected with phenol-killed bacilli in oil. Other groups with fairly high antibody levels were those injected with un-heated tuberculin (twice), with unheated tuberculin in water-in-oil emulsion (once), and with BCG (twice). Animals injected with phenol-killed bacilli in saline and with 5 mg BCG responded less well; there was no evidence of an antibody response in the animals injected once with 0.001 mg BCG. In the skin test animals injected with tuberculoprotein in saline or in water-in-oil emulsion reacted with early type reactions, which were more severe in the latter group. Maximum readings from these reactions were at 3 hours after the intradermal injection of tuberculin. Injections of killed or living bacilli produced skin sensitivity of the delayed type with little or no evidence of an early type reaction, regardless of whether or not circulating antibodies were present. These reactions reached their peak at 24-72 hours, the stronger reactions tending to reach their peak later than weak reactions.