Expression of a human Coxsackie/adenovirus receptor transgene permits adenovirus infection of primary lymphocytes

Replication-defective adenoviruses are effective vehicles for gene transfer , both for the repair of defective genes and for studies of gene function i n primary cells. Many cell types, including lymphocytes, are refractory to adenovirus infection because they lack the Coxsackie/adenovirus receptor (C AR) needed for virus attachment. To extend the advantages of adenovirus-med iated gene transfer to primary lymphoid populations and other cell types la cking endogenous CAR, we produced a mouse that expresses human (h) CAR as a transgene under control of a murine MHC class I promoter. hCAR protein is expressed on T and B lymphocytes from a variety of organs (spleen, lymph no de, bone marrow, thymus, and peritoneum). These lymphocytes are susceptible to adenovirus infection, as demonstrated by reporter green fluorescent pro tein gene expression, with the fraction of expressing cells as high as 70%. Some lymphocyte subpopulations required stimulation subsequent to adenovir us infection for reporter expression. This activation requirement is a rest riction imposed by the promoter used in the adenovirus construct. In subpop ulations requiring activation, the elongation factor 1 promoter was far sup erior to a hCMV promoter for directing green fluorescent protein production . We also find that hCAR mRNA is produced in nonlymphoid tissues from all f ounder lines, including tissues that do not express endogenous murine CAR, suggesting the opportunity for effecting gene delivery to and testing gene function in a wide variety of primary cell types previously resistant to ge ne transfer.