title: The second immunoglobulin class is commonly present in cartilaginous fish belonging to the order Rajiformes.
abstract: Six species of cartilaginous fish distributed into four orders, Rajiformes (skates and guitarfishes), Myliobatiformes (rays), Heterodontiformes (sharks) and Carcharhiniformes (sharks), were investigated for the possible presence of a second class of immunoglobulin (Ig) other than IgM. Among those orders, fish belonging to the order Rajiformes were found to have a second Ig (IgR) with a non-covalently associated dimeric structure in which the H chain was different from that of IgM in mol. wt and antigenicity. Cartilaginous fish belonging to the other orders investigated had only one class of IgM.
mesh_terms: D000818:Animals; D004555:Electric Fish / Q000276:immunology*; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis; D005399:Fishes / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000032:analysis; D007147:Immunoglobulin Light Chains / Q000032:analysis; D007136:Immunoglobulins / Q000032:analysis / Q000145:classification*; D008970:Molecular Weight; D012860:Skates, Fish / Q000276:immunology*
chemical_list: D000939:Epitopes; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007136:Immunoglobulins