Monoclonal antibodies specific for the G1 glycoprotein of La Crosse virus that react with other California serogroup viruses.

Various degrees of cross-reactivity have been observed among members of the California serogroup of bunyaviruses. Since the G1 glycoprotein of La Crosse (LAC) virus, a member of this serogroup, has been shown to contain the antigenic determinants involved in neutralization, monoclonal antibodies to this glycoprotein were used in enzyme immunosorbent and kinetics of neutralization assays with the other California viruses to detect cross-reactive sites that may be involved in neutralization. The results first indicated that five of the antigenic regions previously mapped on the LAC G1 glycoprotein contained overlapping epitopes within them. In all, a total of 16 epitopes within eight antigenic regions were identified on the G1 glycoprotein of LAC virus. One epitope was found on all of the California viruses and is therefore a group-specific antigenic determinant. A LAC-specific epitope was also identified. Different patterns of reactivity were observed among the California viruses for the rest of the antibodies. When the monoclonal antibodies (MAbs) were assayed with the uncloned reference strain of LAC and with two New York isolates, differences were found for epitopes within two antigenic regions. With one exception (snowshoe hare virus, a variety of LAC), pairs of antibodies shown to enhance neutralization of LAC virus did not increase neutralization of the other California viruses having the corresponding pairs of epitopes.