Phagocytosis of Herpetomonas samuelpessoai by mouse peritoneal macrophages: effect of lidocaine, concanavalin A and carbohydrates.

ABSTRACT

Normal mouse peritoneal macrophages, as well as macrophages treated with Concanavalin A (Con A) and lidocaine, were incubated in the presence of normal, Con A-treated or glutaraldehyde-fixed Herpetomonas samuelpessoai. The percentage of infected macrophages, the mean number of protozoa per macrophage and the phagocytic index was determined after 1 and 2 h of protozoa-macrophage interaction. The uptake of H. samuelpessoai by the macrophages was increased when either the protozoa or the macrophages or both were treated with Con A. The effect of Con A was dependent on its concentration and was inhibited by alpha-methyl-D-mannoside. The uptake of H. samuelpessoai by macrophages was significantly inhibited by xylose, mannose and a polysaccharide isolated from the portozoan. Lidocaine-treated macrophages incorporated less protozoa than normal macrophages. Both Con A and lidocaine induced the formation of a large number of cytoplasmic vacuoles in the macrophages. Glutaraldehyde-fixed protozoa were more easily incorporated by the macrophages than living cell. However, their uptake was not stimulated by treatment of the macrophages with Con A.