[A study of neutralizing activity and cross-reactivity of monoclonal antibodies to ectromelia virus with orthopoxviruses pathogenic for man].
ABSTRACT An extensive collection of 125 rat hybridomas secreting monoclonal antibodies (Mabs) to ectromelia virus (EV) polypeptide (Poxviridae family, Orhtopoxvirus genus) was set up. A significant portion of Mabs (37 types) recognized epitopes of the 14 kDa polypeptide as well as the 37 and 35 kDa polypeptides. However, a majority of Mabs interacted with conformation-dependent epitopes, which were destroyed in immunoprecipitation. One hundred and thirteen of Mabs cross-interacted with antigenic determinants of vaccinia viruses (VV), cowpox virus (CPV) and smallpox virus (SPV); only 12 of them were found to be specific to EV. The Mabs antigenic activity was tested for 46 types of cross-reactivity Mabs in VV neutralization on Vero cells. Only the 112H12, 113D5, 113F8, 122H9 and 125G9 Mabs, which were specific to the kDa 14 polypeptide (gene A30L EV), had the neutralizing activity. The 122H9 and 125G9 Mabs were able to neutralize SPV. Therefore, it can be assumed that the 14 kDa polypeptide carries, on its surface, cross-reactivity neutralizing epitopes typical of orthopoxviruses.