ERVW-1 and HIV-1 infection: Retroviral enveloped VLPs presenting HIV-1 envelope are based on the concept that chimeric simian immunodeficiency virus (SIV) Gag VLPs exhibit altered HIV-1 Env glycoproteins with loss of glycosylation and suppression of the V1/V2 loop, which can elicit both humoral and cellular immunity and consequently neutralizing antibodies against HIV-1 infection (Chen et al., 2020). The biggest challenge in this type of HIV-1 based vaccine is focused on downstream purification (Chen et al., 2020).