ERVW-1 and infection: A high number of copies of proviral DNA was determined in nuclei isolated from rhesus monkey PBMC infected by SIV with full length Env, and a significantly lower amount in nuclei infected by SIV with truncated Env at 24 hr post infection: about 1.39 × 106 DNA copies infected by SIVmac239 and about 1.3 × 106 DNA copies infected by SIVmac18, or about 4 × 104 DNA copies infected by SIVmac239T and about 5.3 × 103 DNA copies infected by SIVmac18T (Fig. 3).