Hematopoietic long-term culture (hLTC) for human cytomegalovirus latency and reactivation

Of the many research challenges posed by human cytomegalovirus latency, perhaps the most notable is the requirement for primary hematopoietic cell culture. Culturing hematopoietic subpopulations while maintaining physiological relevance must be given utmost consideration. We describe a long-standing primary CD34(+) hematopoietic progenitor cell (HPCs) system as an experimental model to study human cytomegalovirus (HCMV) latency and reactivation. Key aspects of our model include infection of primary human CD34(+) HPCs prior to ex vivo expansion, maintenance of undifferentiated cells in a long-term culture with a stromal cell support, and an assay to quantitate infectious centers produced prior to and following a reactivation stimulus. Our method offers a unique way to quantitatively assess HCMV latency and reactivation to study the contribution of viral and host genes in latency and reactivation.