CMV-seropositive donor PBMCs exposed to CMV antigen results in endothelial cell damage in cocultures. (A) PBMCs isolated from a CMV-seropositive donor and cocultured with endothelial cells after 5 days are shown. (B) The same donor PBMCs cocultured on endothelial monolayers for 5 days are shown, in the presence of CMV antigen. (C) Control in which endothelial monolayers alone were maintained for 5 days. (D) CMV-seronegative donor PBMC exposed to the same conditions had no effect on endothelial cell monolayers and are indistinguishable from panel C. Results are representative of 6 different CMV-seropositive and -seronegative donor pairs.