The pathogenesis of Yaba virus-induced histiocytomas in primates.

Abstract

Benign histiocytomas, detectable histologically by the 3d day, regularly followed subcutaneous inoculation of cell-free saline suspensions of the tumor into rhesus monkeys. Proliferation proceeded rapidly during the initial 2 weeks, producing a tumor of characteristic cell type and pattern. No cell other than certain primate tissue histiocytes has been shown to be a susceptible host. Regression was an individual cell phenomenon, beginning while proliferation was still active but gaining in prominence over a period of 2–3 months. Circulating neutralizing antibody was ineffective in preventing growth of the established tumor. Following tumor regression, plasma cells and lymphocytes marked the site, but fibrosis did not occur. Intravenous inoculation of virus was followed by the appearance of many tumors in heart, lungs, muscles, and subcutaneous tissues of the monkeys. Similar tumors developed locally following direct inoculation of virus incorporated in Freund's complete adjuvant into liver, spleen, or kidney. No tumors developed when virus was injected subcutaneously into rats, guinea pigs, and rabbits. Although histiocytes predominated in the guinea pig reaction, the cells were not transformed, and fibrosis developed at the inoculum site.