VARIATION IN THE NATURE OF ATTACHMENT OF PHOSPHORYLCHOLINE TO EXCRETORY-SECRETORY PRODUCTS OF ADULT BRUGIA-PAHANGI

The mechanism of linkage of phosphorylcholine (PC) to excretory-secret ory products (ES) of adult Brugia pahangi has been investigated. Biosy nthetic radio-isotope labelling of ES with [H-3]choline followed by SD S-PAGE/fluorography revealed a smear of molecular weight approximately 40-100 kDa which loses its radiolabel following exposure to N-glycosi dase F, but not mild alkali. PC is thus attached to this smear of mole cules via N-type glycans, a mechanism of linkage previously observed w ith respect to PC-ES of Acanthocheilonema viteae. Western blotting ana lysis of nonradiolabelled ES demonstrated the existence of additional PC-ES which were insensitive to N-glycosidase F, but not to alkali. Th is second group of molecules is therefore likely to contain PC linked to O-glycans. Filarial nematodes may thus utilize 2 classes of glycan for attachment of PC. Examination of B. pahangi and A. viteae whole wo rm extracts by Western blotting indicated that their PC content could not be cleaved by N-glycosidase F and hence the use of N-type glycans may be restricted to a subset of ES products. The implications of thes e findings with respect to developing inhibitors of PC attachment for use as anti-filarial drugs are discussed.