Complete replication of human cytomegalovirus in explants of first trimester human placenta

Tissue integrity and viability of first trimester placenta explants were obtained in culture for 3 weeks. Explants were infected with human cytomegalovirus (HCMV), several cycles of HCMV replication were obtained and the progression of the infection was observed within a tissue that maintains its normal cellular organization. In agreement with recent clinical data, 3 weeks were necessary for the virus to colonize the placenta fully. Complete HCMV replication was observed in trophoblasts, followed by subsequent transmission of the infection to the stromal fibroblasts and fetal endothelial capillary cells. Viral DNA replication was monitored and the production of infectious viral progeny documented.