New derivatives of 5-amino-3-methyl-4-isothiazolecarboxylic acid and their immunological activity.

Several new compounds - 4 and 5-substituted derivatives of 3-methyl-4-isothiazolecarboxylic acid were synthesized. These compounds have aminoacylamino groups in position 5 of the isothiazole ring. In position 4, the carboxylic group was replaced by ethyl ester. The biological activites of the obtained compounds were analyzed in the humoral immune response and delayed type hypersensitivity reaction to sheep red blood cells (SRBC) in the mouse model, as well as in the proliferative response of splenocytes to T-cell and B-cell mitogens in vitro.