Inhibition of lymph node metastasis of P388 leukemia by bestatin in mice.

Bestatin, a chemically defined immunostimulant of low molecular weight, suppressed the gradually-occurring lymph node metastasis of P388 leukemia in CDF1 mice when administered i.p. at the doses of 1 approximately 30 micrograms/mouse. It could not, however, suppress the established large metastasis of P388 leukemia. Lymph node cells isolated from the mice given bestatin i.p. at 1 and 30 microgram/mouse showed cytostatic activity against P388 leukemic cells in vitro than those from the untreated mice.