ERVW-1 and infection: In Jurkat cells infected with a spinoculation method, HIV Env-V4/V5 sfGFP constructs all displayed a lower infection efficiency as compared with wild type Env construct NL-sfGI, and the increase in GFP over time was less sustained over time, relative to MT4 cell infection, indicative of a lower efficiency of spread in these cells (Figure 1G).