Heavy and light chain sequences of four monoclonal antibodies that bind galactosylgloboside (GalGb4)

Abstract We recently described IgM monoclonal antibodies directed against the glyco‐spingolipid galactosylgloboside (GalGb 4 ; Marcus, M. D. et al., Arch. Biochem. Biophys . 1988. 262 : 620). We now present the nucleotide and deduced amino acid sequences of the heavy and light chains of these antibodies. The antibodies were generated in a single fusion, their heavy as well as their light chains are almost identical, and they appear to be clonally related. The light chains were encoded by J x 5 and a V x gene belonging to the Oxl family, but they are only 93% homologous to the most closely related germ‐line gene, and they are probably encoded by a germ‐line gene that has not yet been identified. The heavy chains were all encoded by V H 441 and J H 2, and have identical N segments. The V H 441 germ‐line gene encodes a potential glycosylation site at Asn 58 in the complementarity‐determining region 2. This site, which has been retained in all V H 441‐encoded monoclonal antibodies sequenced previously, was mutated out by a single base change in all four anti‐GalGb 4 antibodies.