HHV-6BPL1 entry correlates with the expression of CD46 isoform patterns. High expression of CD46-BC2 correlates with HHV-6BPL1 infection. Low expression of CD46-CYT-1 inversely correlates with HHV-6BPL1 infection. Anti-CD46 antibodies block HHV-6BPL1 entry in SupT1 cells. Heparin does not affect binding of HHV-6BPL1 to Molt3 cells.