Immune Transfer Protects Severely Immunosuppressed Mice from Murine Cytomegalovirus Retinitis and Reduces the Viral Load in Ocular Tissue

Cytomegalovirus (CMV) retinitis is a sight-threatening disease that affects immunosuppressed people and is prevalent in people with AIDS. The purpose of this study was to evaluate murine CMV (MCMV) retinitis in a replenishing model with adoptive immune transfer into severely immunosuppressed animals. Adult BALB/c mice, immunosuppressed with cyclophosphamide, were infected subretinally with 5x102 plaque-forming units of MCMV. Four to six hours later, 3-4x107 donor cells were transferred by intravenous infusion. Eight days after the transfer, the eyes that had received donor cells were studied histologically, titered for infectious virus, and analyzed with polymerase chain reaction (PCR). Adoptive transfer of total MCMV-immune lymph node (LN) cells or enriched LN lymphocytes specifically and significantly protected immunosuppressed mice from retinitis even after the initiation of infection. The transfer resulted in a reduced viral load, as measured by both plaque assay and PCR. This replenishment model will be useful for determining the specific immune parameters of protection from CMV retinitis.