SERINC5 and infection: To test whether Nef-dependent differences in infection of indicator cell lines (Fig 2B) were due to differential efficacies in SERINC5 antagonism, we cotransfected HEK293T cells with proviral HIV-1 NL4-3 constructs containing various nef alleles, as well as SERINC5 expression or control plasmid and measured infectious virus production two days later.