Detection of Vmp-1. Immunoblotting of selected isolates using the polyclonal antisera generated against the C-terminal part of Vmp-1 from isolate 132. Isolates 132, 5941, DC63 and SC4 show a sharp band around 160 kDa, thus demonstrating the expression of Vmp-1 in these isolates. The polyclonal antiserum additionally reacted with multiple bands around 100 kDa. These bands probably corresponds to a ~100 kDa M. hominis protein which previously has been shown to bind Ig-molecules unspecifically. This protein has not been observed in PG21. The right panel shows the coomassie stained, recombinant Vmp-1 C-terminal fragment used for immunization.