Suppression of adjuvant disease by bacterial extracellular products.

The intradermal injection of a suspension of heatkilled mycobacteria in oil (Freund's adjuvant) produces in the rat a generalized disease, adjuvant arthritis or adjuvant disease (Pearson and Wood, 1959). This can be transferred to syngeneic recipients with lymphoid cells from adjuvant-injected donors but not with serum (Waksman and Wennersten, 1963; Pearson and Wood, 1964a; Quagliata and Phillips-Quagliata, 1972) and is therefore considered to be a manifestation of delayed-type or cellular hypersensitivity to disseminated component(s) of the mycobacterium (Quagliata and Phillips-Quagliata, 1972). In addition, the inflammatory reaction at the site of adjuvant injection provides a useful experimental model for the study of inflammation (Perper, Alvarez, Schroder, and Colombo, 1971). Antilymphocyte serum (ALS), among its many immunosuppressive properties, has been shown to suppress adjuvant disease (Currey and Ziff, 1968). Another property of ALS is that it stimulates the transformation of lymphocytes into large blast-like cells capable of mitosis (Woodruff, Reid, and James, 1967). Streptococcal culture filtrates have recently been shown to have a similar effect on lymphocytes (Taranta, Cuppari, and Quagliata, 1969; Taranta and Cuppari, 1970); we therefore thought it might be of interest to investigate the effect of such filtrates on adjuvant disease. Cellular components of Gramnegative bacteria have previously been shown to prevent adjuvant disease if injected in incomplete adjuvant, but not in saline, before the eliciting adjuvant injection (Wood and Pearson, 1962). We report that some preparations of Grampositive as well as Gram-negative bacterial extracellular products injected subcutaneously (s.c.) in saline starting the day before the adjuvant injection markedly suppress adjuvant disease. Material and methods