Two major antigenic polypeptides of molluscum contagiosum virus

A library of molluscum contagiosum virus (MCV) transferred into the cowpox vector expression system was screened with 12 sera from molluscum patients. Two recombinant proteins of 70 and 34 kDa were detected by immunoblotting and mapped to the open-reading frames MC133L and MC084L, respectively. Consensus sites were found between the C-terminus of the 70-kDa MCV protein and the 14-kDa fusion protein of vaccinia and variola virus, and between the 34-kDa MCV protein and the 37.5-kDa viral membrane-associated protein of vaccinia and variola virus. Rabbit antisera against these two proteins were prepared. An immunofluorescence study demonstrated that the 70- and 34-kDa proteins were predominantly expressed on the surface of recombinant virus-infected HeLa cells, indicating the potential to be inserted into the membrane. On immunoelectron microscopy, antiserum against 70-kDa protein showed significant labeling of the MCV membrane, while the antiserum against 34-kDa protein failed to do so.