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

The immunoglobulin fraction was purified from the plasma of an Antarctic teleost,Chionodraco hamatus(Lönnberg, 1906) by thiophilic adsorption chromatography and size-exclusion FPLC. Somatic proteins ofContracaecum osculatumlarvae were recovered by boiling whole nematodes in phosphate buffer containing 2% SDS and 10% β-mercaptoethanol. Immunoglobulins fromC. hamatusplasma recognisedC. osculatumsomatic antigens either blotted onto nitrocellulose or immobilised on a HiTrap NHS-activated column. The relative molecular mass of the majorC. osculatumantigen was 91 kDa. Plasma from specimens ofC. hamatus,Notothenia coriiceps(Richardson, 1844),Notothenia gibberifrons(Lönnberg, 1905),Chaenocephalus aceratus(Lönnberg, 1906),Pseudochaenichthys georgianus(Norman, 1937),Trematomus bernacchii(Boulenger, 1902) were tested in double immunodiffusion againstC. osculatumproteins. 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.