6. Immunoglobulins In bony fish and other jawed vertebrates, the adaptive immune system relies on B and T cells and on the tremendous variety and specificity of their antigen receptors, the immunoglobulins (IG) or antibodies, and the T cell receptors, respectively [165,166]. Immunoglobulins are the main constituents of the immune response against pathogens [30]. Among the mechanisms implying hum..