Antigenic cross-reaction between the alpha types of human and mouse interferon

Cross-neutralization of the alpha and beta types of human and mouse interferons was tested using antibodies directed against the heterologous types of interferons. The alpha type of mouse interferon (MuIFN-alpha) prepared from L cells was found to be completely neutralizable by high-titered antibody against human alpha-type interferon (HuIFN-alpha), although the titers were much lower than those obtained in neutralization reactions with the homologous interferon. MuIFN-alpha from virus-induced lymphocytes, as well as non-glycosylated MuIFN-alpha from L cells, reacted similarly. The cross-reaction was also observed by the binding of anti-HuIFN-alpha antibody to a column of immobilized MuIFN-alpha. The binding experiment indicated that only a small fraction of the anti-HuIFN-alpha antibody population is heterologous reactive. Reciprocally, HuIFN-alpha from L cells, again with relatively low antibody titers, and the antibody responsible for the heterologous reaction was shown to be the anti-MuIFN-alpha and not anti-MuIFN-beta type. It is concluded that the alpha types of human and mouse interferon bear an antigenic homology. On the other hand, no significant antigenic cross-reactivity has been detected between the beta types of human and mouse interferons.