Studies on Tuberculin Fever

Abstract

Evidence has been presented that the fever elicited by intravenous administration of old tuberculin (O.T.) in BCG-infected rabbits is a specific property of this hypersensitivity system and is probably not due to contamination of tuberculin with bacterial endotoxins. Daily injections of O.T. in sensitized animals resulted in a rapid tolerance to its pyrogenic effect. Tuberculin tolerance can be differentiated from that occurring with endotoxins and was invariably associated with the development of a negative skin test. The mechanism of this tolerance would thus appear to be desensitization. A circulating pyrogen found during tuberculin fever was indistinguishable in its biologic effects from endogenous pyrogens obtained in several other types of experimental fever. This material produced fevers in normal recipients and therefore may be clearly differentiated from O.T. itself which was pyrogenic only to sensitized animals. Since the titer of serum pyrogen was directly proportional to the degree of fever induced by injection of O.T. in the donor animals, a causal relation is suggested. On the basis of these findings, it is postulated that tuberculin fever is due to a circulating endogenous pyrogen released by a specific action of O.T. on sensitized cells of the host.

Studies on Tuberculin Fever

“…4 a depicts the mean changes in body temperature induced in both BCG-sensitized and normal rabbits given 100 mg OT intravenously. As previously reported, sera transferred from sensitized donors during fever produced immediate transient fevers in normal recipients indicating the presence of a circulating EP (1,10). Normal animals, on the other hand, remained afebrile after a similar injection of OT and their sera were nonpyrogenic when given intravenously to recipient rabbits.…”

“…Techniques for plotting temperature responses and fever indices of injected rabbits have been presented earlier (1,2).…”

“…Sensitization of Rabbits.--The strain of BCG used, techniques for its culture and harvesting, and methods of inoculating donor rabbits were identical, except where indicated, to those already presented (1,2). Sensitization to products of this bacterial strain was achieved by intravenous injection of 2 mg BCG in fine suspension in saline.…”

“…Temperature Recording.--Rectal temperatures were measured with Foxboro rabbit scanning equipment (1,2). Rabbits were restrained either in stalls or in metal boxes with openings for the head and tall.…”

ANALYSIS OF HISTAMINE RECEPTORS IN THE CENTRAL THERMOREGULATORY MECHANISM OF Mastomys natalensis

“…The 'temperature index' for each animal and each group along with s.e. was also calculated according to the planimetric method of Hall & Atkins (1959) to take into account the magnitude as well as duration of change of temperature. The significance of the difference between the treated and the untreated group was assessed by Student's t 3test.…”