[Immunomodulating properties of khlotazol].

A nonsteroidal anti-inflammatory agent khlotazol administered to rats in doses of 40-80 mg/kg for 5 days stimulated synthesis of IgM- and IgG-antibodies to ram erythrocytes and increased the number of antibody-forming cells (AFC) and rosette-forming cells (RFC) in the spleen. When the doses were increased to 160-320 mg/kg, the stimulating effect of the drug on the production of hemagglutinins retained but dose-dependent inhibition of the number of AFC and RFC was found. When administered in a dose of 80 mg/kg khlotazol markedly activated the reaction of hypersensitivity of delayed type induced by ram erythrocytes.

Further studies of the adjuvant properties of homologous IgG split products: mode of action of F(ab')2 and related fragments.

Peptic bivalent and monovalent Fab' fragments as well as F(ab')2 fragment from a purified rabbit anti-DNP antibody were equally effective in enhancement of the immune response to SRBC. In contrast, the papain Fab fragment of normal IgG possessed a considerably lower enhancing activity. These data indicate that the effector site(s) controlling the adjuvant activity of F(ab')2 and related fragments is structurally distinct from the antibody active site(s) within the fragment molecule, and is located in C-terminal region of the heavy chain Fd fragment.