Comparison of techniques for recovering murine cytomegalovirus from a macrophage-enriched subpopulation of mice.

We previously demonstrated the transmission of murine cytomegalovirus to syngeneic mice and preformed monolayers of mouse embryo fibroblasts with plastic-adherent peritoneal exudate cells from infected mice as a source of macrophages. In the present studies we compared this standard feeder layer method with a reverse feeder layer method in which the adhering peritoneal exudate cells remained attached to plastic and to which were added mouse embryo fibroblasts. Recovery of virus from the adherent peritoneal exudate cells of infected mice was achieved with both methods. Whereas the standard method achieved greater accuracy and usually recovered more virus, the reverse method appeared to recover virus more frequently and required fewer cells to perform the assay. Furthermore, the reverse method demonstrated the survival of murine cytomegalovirus in adhering cells after culture periods of up to 2 weeks.