Microneme secretion in Coccidia: confocal laser scanning and electron microscope study of Sarcocystis muris in cell culture
Entzeroth, R.; Kerckhoff, H.; König, A.
European Journal of Cell Biology 59(2): 405-413
1992
ISSN/ISBN: 0171-9335 PMID: 1493806 Document Number: 398460
A monoclonal antibody (MAb) raised against a subcellular fraction of Sarcocystis muris cystozoites was used to localize microneme antigens before, during and after invasion of cultured cells. The MAb recognized a 20 000 and a 22 000 MW protein under reducing and non-reducing conditions on Western blots and localized an antigen in cystozoites in the apical part of the parasites. Confocal laser scanning microscopy of invading cystozoites revealed the secretion of a microneme antigen at the apical tip of the parasite. The secreted microneme antigen was attached to the host cell surface at the invasion site and spread along the surface of the infected cells. Electron microscopy using immunogold labeling showed that the microneme antigen was distributed in patches on the surface of infected cells and present on infected cells more than 60 minutes pi. The function of microneme antigens during parasite-host interactions is discussed.