Specific mAbs against HLA-DR antigens functionally convert BMo to a CMo-like virus.

CMo- and BMo-derived virions were incubated with saturating concentration of anti-HLA class II DR subset mAb D1.12 for 2 hours at 4°C and for 2 hours at 37°C before contact with the IL-3–deprived TF-1 cells. (A) EMSA using the PRE probe and 8 μg WCE from TF-1 cells exposed to either CMo or BMo viruses that were pretreated (lanes 3-4) or left untreated (lanes 1-2) with anti-HLA-II/DR specific mAbs D1.12. (B) Immunoblot analysis using the same WCEs (15 μg) of the EMSA of panel A and anti–phospho-STAT5 antibodies (first panel). In the second panel the filter, after stripping, was hybridized with a mixture of anti-STAT5A and anti-STAT5B antibodies.