Importantly, no CasBrE Env immunostaining was observed in control NSCs with or without 4070A infection; however, CasE-NSCs, showed significant CasBrE Env expression both in the presence and absence of 4070A infection, with a small but reproducible increase in cell surface CasBrE Env after 4070A infection. The gene discussed is ERVW-1; the disease is infection.