Production, characterization, and evaluation of polyclonal antisera specific to stellate sturgeon (Acipenser stellatus) immunoglobulin

Sturgeon species are commercially important species in finfish aquaculture industry. Till now, a small number of studies have been reported on the immune responses in sturgeon species against infectious diseases. Monoclonal and polyclonal antibodies in fish immunoglobulins (Igs) are essential to evaluate the humoral immune response. This study aimed to produce, characterize, and evaluate the polyclonal antisera against stellate sturgeon Igs. For the production of polyclonal antibodies against fish Igs, stellate sturgeon serum Igs was isolated using the ammonium sulfate precipitation method. The purified Igs with the Freund adjuvant was injected subcutaneously in to sheep (Ovis aries). Then, anti- stellate sturgeon Ig antibody titer and specificity were determined using ELISA and Western blot techniques. Stellate sturgeon Ig antibodies were detected in the immunized animals and were significantly higher in the immunized group compared to the non-immunized group. The polyclonal antisera showed a high specificity to the immunoglobulin heavy )H( chain of stellate sturgeon and moderately cross-reacted with the immunoglobulin H chain in Siberian (Acipenser baerii) and ship (A. nudiventris) sturgeons but did not show reactivity with rainbow trout (Oncorhynchus mykiss) serum Igs. It was indicated that the produced polyclonal antisera should be further investigated to be used for immune-diagnostic purposes in sturgeon species upon exposure to various infectious diseases.