- Primary human immunodeficiency virus type 2 (HIV-2) isolates, like HIV-1 isolates, frequently use CCR5 but show promiscuity in coreceptor usage. Mörner, A., Björndal, A., Albert, J., Kewalramani, V.N., Littman, D.R., Inoue, R., Thorstensson, R., Fenyö, E.M., Björling, E. J. Virol. (1999)