Development and characterisation of monoclonal antibodies against seabass immunoglobulinsDicentrarchus labraxLinnaeus, 1758

Two monoclonal antibodies (MAbs) against seabass (Dicentrarchus labrax) immunoglobulin (IgM) were obtained after lymphocytic hybridisation made from mouse splenocytes. Screening, using an indirect enzyme-linked immunosorbent assay (ELISA), revealed two probes which had a specific activity against seabass IgM and did not react with turbot, sea bream, eel and rainbow-trout IgM. These probes belonged to a sub-class of IgG2a and recognised exclusively the heavy chains (H) of seabass IgM on immunoblotting. Their immunological activity was characterised by using ELISA and immunocytochemistry tests. The 50% binding titers were approximately at dilution 105and the MAbs reacted with IgM+cells from smears of the head kidney and spleen of the seabass. In both methods, the specific activity was inhibited by using seabass IgM in solution.