Though we still observed some loss of ITS103.01LS-F(ab’)2 binding to SIV Env expressing cells in the presence of some chronic plasma samples due to competing endogenous proteins, the loss was more variable and significantly lower than 7D3 binding loss (% loss = 0–58%, average loss = 18%, n = 15, Log10 PVL range = 1.6–7.8 copies/mL) with some animals showing no loss, and as expected, the loss strongly correlated with the length of untreated SIV-infection (ρ = 0.77, P < 0.001, Fig. 2d). This evidence concerns the gene ERVW-1 and infection.