- The trophoblastic epithelial barrier is not infected in full-term placentae of human immunodeficiency virus-seropositive mothers undergoing antiretroviral therapy. Tscherning-Casper, C., Papadogiannakis, N., Anvret, M., Stolpe, L., Lindgren, S., Bohlin, A.B., Albert, J., Fenyö, E.M. J. Virol. (1999)