Antigenic characterization of Enteromyxum leei (Myxozoa: Myxosporea)

Abstract

Enteromyxum leei, an intestinal myxozoan parasite affecting a wide range of fish, was partially purified, and the immunogenic composition of its glycoproteins as well as the proteolytic activity were studied. Parasite extracts, mainly containing spores, were separated by SDS-PAGE, and thereafter, immunoblots were carried out with a polyclonal antiserum (Pab) raised against E. leei. Periodic acid/Schiff staining of gels, periodate- and Proteinase K-treated Western blots and Lectin blots were performed to analyse the terminal carbohydrate composition of the parasite's antigens. Additionally, the cross-reaction of the parasite extracts with a Pab raised against the polar filament of the myxozoan Myxobolus pendula was studied. Both Pabs detected proteic epitopes on antigenic proteins and glycoproteins of E. leei, ranging between 15 and 280 kDa. In particular, 2 glycoproteic bands (15 and 165 kDa), immunoreactive to both Pabs and with glucose and mannose moieties, could correspond to common antigens shared among myxozoans. The 165 kDa band also presented galactose, N-acetyl-galactosamine and N-acetyl-glucosamine, pointing to its possible origin on chitin-built spore valves and to its possible involvement in host-parasite interactions. The molecular weight of the 15 kDa glycoproteic antigen matches that of minicollagen, a cnidarian-specific protein of nematocysts with a myxozoan homologue. Several proteases with apparent molecular weights ranging between 43 and 245 kDa were found in zymographies of E. leei extracts, and these may have a potential role in the parasite's pathogenesis. This is a useful approach for further studies to detect targets for antiparasitic therapy.

Insights into myxozoan composition and physiology revealed by histochemical properties of myxospores

“…The Luna stain, used to identify the chitinous endospore walls of microsporidia, uniformly highlighted shell valves in six of the eight myxozoan species examined (Peterson, Spitsbergen, Feist, & Kent, 2011). This is consistent with previous reports of chitin as a component of shell valves, and occasionally other myxospore structures, demonstrated by lectin histochemistry (Estensoro, Álvarez‐Pellitero, & Sitjà‐Bobadilla, 2013; Lukes, Volf, & Lom, 1993). The PTAH stain, commonly used to demonstrate fibrin and muscle striations, presumptively stained the microfibrils and sutural junction of the valve cells.…”

Acquired protective immune response in a fish-myxozoan model encompasses specific antibodies and inflammation resolution

“…One of these studies also detected up-regulation of soluble and membrane IgM only at the PI 64 days after anal intubation with the parasite, which provoke a faster progression of the infection [26]. With both experimental transmission methods a concomitant significant increase of IgM + B cells occurred in the PI and HK [27,32] [26,27,61]. These Igresponses by the host were now shown to shift quite late during parasite invasion from non-specific to specific.…”

The kinetics of cellular and humoral immune responses of common carp to presporogonic development of the myxozoan Sphaerospora molnari

“…To elucidate the nature of the B cell responses, we investigated the presence of specific antibodies to S. molnari by SDS PAGE of parasite antigens and subsequent western blotting with sera of infected fish, which identified a single protein of 16 kDa. While the identity of this protein remains to be determined, it is noteworthy that an antigenic protein of the same size (and an additional 165 kDa protein) was characterized in E. leei , using a similar approach [99]. The two proteins could well correspond to common antigens shared among myxozoans.…”