Presence of antibodies specific for proteins of Contracaecum osculatum (Rudolphi, 1908) in plasma of several Antarctic teleosts

The immunoglobulin fraction was purified from the plasma of an Antarctic teleost, Chionodraco hamatus (Lonnberg, 1906) by thiophilic adsorption chromatography and size-exclusion FPLC. Somatic proteins of Contracaecum osculatum larvae were recovered by boiling whole nematodes in phosphate buffer containing 2% SDS and 10% P-mercaptoethanol. Immunoglobulins from C. hamatus plasma recognised C. osculatum somatic antigens either blotted onto nitrocellulose or immobilised on a HiTrap NHS-activated column. The relative molecular mass of the major C. osculatum antigen was 91 kDa. Plasma from specimens of C. hamatus, Notothenia coriiceps (Richardson, 1844), Notothenia gibberifrons (Lonnberg, 1905), Chaenocephalus aceratus (Lonnberg, 1906), Pseudochaenichthys georgianus (Norman, 1937), Trematomus bernacchii (Boulenger, 1902) were tested in double immunodiffusion against C. osculatum proteins. Immunoprecipitates were observed with individual plasma of five out of six species. The results demonstrate the presence of nematode-specific antibodies in Antarctic fish plasma. (C) 1998 Academic Press Limited.