Phagocytosis of Giardia muris by macrophages in Peyer's patch epithelium in mice

Abstract

No mechanism for the initiation of immunological clearance of Giardia from the mammalian intestinal tract has been identified. In normal and nude mice experimentally infected with G. muris, we examined antigen-sampling epithelium over Peyer's patch follicles by electron microscopy for evidence of interaction between G. muris and lymphoid cells. Invading G. muris were found in the epithelium near dying or desquamating columnar cells. Macrophages beneath the basal lamina extended pseudopods into the epithelium, trapping invading G. muris and enclosing them in phagolysosomes. In normal mice, which clear G. muris in 4 to 6 weeks, macrophages containing digested G. muris were surrounded by rosettes of lymphoblasts in the epithelium. In nude mice deficient in lymphocytes, there was apparent hyperplasia of macrophages, which filled the follicle domes, resulting in more frequent entrapment of G. muris but no contact between macrophages and lymphoblasts in the epithelium. In nude mice, which require 6 months to control G. muris infection, lymphoblast contact with macrophages containing distinctive microtubular remnants of G. muris was only identified in the follicle dome. This close physical association of lymphoblasts and macrophages containing G. muris remnants suggests that this macrophage activity represents intraepithelial antigen processing as well as a defense against the effects of the uncontrolled entrance of microorganisms and other antigenic particles into Peyer's patch lymphoid follicles.

Morphometric and cytochemical analysis of lysosomes in rat Peyer's patch follicle epithelium: Their reduction in volume fraction and acid phosphatase content in M cells compared to adjacent enterocytes

“…Presence of activated lymphoblasts in the meshes of M cell cytoplasm is consistent with the hypothesis that M cells take up particulate antigen from the intestinal lumen and transport it across their cytoplasm to the intercellular spaces ( Fig. 31, (Owen et al, 1981(Owen et al, , 1986aBockman and Boydston, 1982). In macrophages the process of endocytosis stimulates lysosome formation (Cohn, 1963), which we have not observed in M cells even when great numbers of transport vesicles are present.…”

Immune effector responses to an excretory-secretory product of Giardia lamblia

“…Alternatively there may have been an interaction of viable trophozoites with the surface epithelium resulting in activation and uptake by tissue macrophages. In support of this hypothesis is the work by Owen et al [68], who demonstrated phagocytosis of G. muris by macrophages present in mouse PP. The immunisation of animals with ES antigen resulted in a signi¢cant titre of anti-ESP antibodies indicating that this protein is highly immunogenic and it seems that ESP is one of the major antigens of G. lamblia responsible for protection against the disease.…”

Differential distribution of lymphocytes and accessory cells in mouse Peyer's patches

“…Cells within the dome of the Peyer's patch have also been considered to defend against microorganisms entering uncontrolled into the lymphoid follicle (Owen et al, 1981). Although macrophages have been observed in the dome epithelium with electron microscopic techniques (Abe and Ito, 1977;Owen et al, 19811, labeling with anti-Mac-1 indicates that they are found primarily in the subepithelial region.…”

“…In addition to lymphocytes, dendritic cells and macrophages have been found in the epithelium and subepithelial area of the dome (Mayrhofer et al, 1983;Wilders et al, 1983;Abe and Ito, 1977;LeFevre et al, 1979;Owen et al, 1981). These accessory cells have been implicated in the processing of intestinal antigens and defense against microbial invasion, respectively Inaba et al, 1984;McGhee et al, 1984;Owen et al, 1981). In vitro studies have shown that interaction of Ia+ dendritic cells and helper T cells is necessary for the production of antibody by isolated Peyer's patch B cells Spalding et al, 1984); however, where these interactions occur in vivo is not known.…”