We infected K562 cells expressing human or sparrow PCDH10 with Imperial 181 RVPs at different multiplicities of infection (MOI), with RVP titers determined on Vero E6 cells, which can be infected by Imperial 181 RVPs independently of PCDH10 or LDLR-related proteins.15 Though Imperial 181 RVPs recognized sparrow PCDH10 to infect K562 cells, they required a much higher MOI than McMillan or 71V RVPs to reach 50% infection (Figure 4D), suggesting that Imperial 181 uses sparrow PCDH10 less efficiently as a receptor. Here, LDLR is linked to infection.