Immunomodulation by the new synthetic thiazole derivative tiprotimod. 2nd communication: immunopharmacological...

The thiazole derivative [2-(3-carboxy-1-propylthio)-4-methyl-1,3-thiazole] acetic acid (tiprotimod, HBW 538) a new synthetic immunopotentiator of low molecular weight, has been tested in vivo and ex vivo in various experimental models. Its influence on parameters of macrophage functions, on DTH (delayed type hypersensitivity)-reaction and antibodies to sheep erythrocytes (SRBC), Tetanus toxoid and heatkilled E. coli bacteria in mice, and in the popliteal lymph node assay in rats was investigated. When mice were treated with the test substance i.v., i.p., or p.o. in a dose range from 1-100 mg/kg, a time and dose-dependent stimulation of macrophage activity was observed. The drug was able to enhance the DTH-response against SRBC and to stimulate the humoral immune response against Tetanus toxoid and heat-killed E. coli. In the popliteal lymph node assay, a murine graft-vs-host model, a stimulating effect of the substance was observed when it was administered at the same time of the grafts to rats. These results demonstrate that tiprotimod is a potent immunopotentiator for both humoral and cell mediated immune response in experimental animals.