STUDY ON THE TUBERCULOSTATIC FACTOR OF MAMMALIAN SERUM.

Abstract

Studies of the effects of serum from various mammals upon the tubercle bacillus have generally been limited in the time of contact between the bacillus and the investigated serum, and in the use of diluting media which can neutralize tuberculostasis. It was shown in previous reports that the latter limitation is mainly responsible for failures to demonstrate a strong antimycobacterial activity in immune guinea pig and normal human serum (1, 2)when these sera were diluted in various citrateor phosphate-containing media, tuberculostasis was vitiated. The use of different media for the dilution of investigated serum is the principal cause of the contradictory results reported in the literature. Thus, Kirchner (3) and Boissevain (4) diluted human, guinea pig, sheep, rabbit, and horse serum in synthetic media and concluded that these sera stimulated the growth of human tubercle bacilli, and that such serummedium mixtures could serve as an excellent medium for the growth of these organisms. Raffel (5), in discussing immunity in tuberculosis, indicated that there is no specific evidence in the literature to suggest that the serum of normal animals is tuberculostatic-virulent as well as avirulent bacilli grow very well in vitro in normal serum as a medium. Contrary to these findings, Hedvall (6) reported that serum specimens from man, horse, cow, dog, cat, rabbit, and guinea pig act as inhibitors of bacillary growth. In the present work, the effects of various mammalian serum samples upon the growth of tubercle bacilli were tested and an investigation made of ways of purification of the tuberculostatic factor which is present in most of the tested serum.