NOVEL LACTO-GANGLIO TYPE GANGLIOSIDES WITH G(M2)-EPITOPE IN BOVINE BRAIN WHICH REACT WITH IGM FROM A PATIENT OF THE AMYOTROPHIC LATERAL SCLEROSIS-LIKE DISORDER

A motor neuron disorder resembling that of amyotrophic lateral scleros is was found in a patient who had received the intramuscular administr ation of a mixture of bovine brain gangliosides (Yuki, N., Sato, S., M iyatake, T., Sugiyama, K., Katagiri, T., and Sasaki, H. (1991) Lancet 337, 1109-1110). A very high titer of anti-G(M2) IgM was detected in t he patient's serum and the patient quickly recovered after plasmaphere sis. The clinical course of the patient appeared to be different from amyotrophic lateral sclerosis and the anti-G(M2) IgM was thought to be the culprit. The IgM reacted with G(M2), G(M1b)-GalNAc, SPG(alpha2-3) -GalNAc, and G(D1a)-GalNAc, but not with G(A2) or G(D2), meaning that the epitope recognized by the IgM was the G(M2)-like terminal structur e, GalNAcbeta1-4(Neu-Acalpha2-3)Galbeta1-. In this study, we found two novel G(M2)-epitope containing gangliosides, X1 and X2, in bovine bra in gangliosides by TLC immunostaining using the patient's IgM. They we re characterized as unique lacto-ganglio type gangliosides containing the following branching structures. Their unusual structures may be im munogenic to humans to induce anti-G(M2) antibody.