Ultrastructure of the Cuticle of Brugia pahangi: a Rich Source of Antigen

Abstract

Abstract

The cuticle is a rich source of antigen of the filarial parasite, Brugia pahangi, as revealed by indirect immunofluorescent study. Transmission electron microscopy reveals that the cuticle of the L3 and adult B. pahangi is surrounded by a discontinuous trilaminate membrane-like epicuticle. This is one of the richest sources of antigens, because this structure is in direct contact with host immunity. The cuticle comprises the basal, middle and cortical layers, with no clear demarcation between each layer. All layers comprise fine filamentous structures arranged in several directions. These fibrils of the cuticle are believed to be collagen-like protein, but comprised of finer fibrils, with no periodicity. These cuticular proteins may be slowly turned over and released to the environment and act as one source of immunogen. The hypodermis shows cellular components in the lateral cords. Each cell bears organelle characteristics of highly synthetic activity and infolded plasma membranes at both apical and basal regions. Therefore, in addition to its role in synthesizing cuticular proteins, the infolded plasma membrane may play roles in controlling and facilitating the exchange of nutrient and waste materials through the cuticle. These excreted materials may also be another source of antigen.

Keywords : ultrastructure, cuticle, Brugia pahangi