XENOGENEIC MOUSE FIBROBLASTS PERSIST IN HUMAN CULTURED EPIDERMAL GRAFTS - A POSSIBLE MECHANISM OF GRAFT LOSS

Recent reports suggest that long-term graft take of cultured epidermal autografts (CEAs) is less than 50% when late graft loss is considered , The characteristics of late CEA loss suggest that it may occur as a result of an immunologic reaction to persistent xenogeneic cells and/o r proteins used to grow CEA, In this study we examined whether immunol ogically reactive, mouse 3T3 fibroblasts used as feeder layers can per sist in primary, secondary, and tertiary human CEA, We cocultured kera tinocytes from 11 separate burn patients,vith growth-arrested 3T3 fibr oblasts, After removing visible 3T3 fibroblasts from CEA with trypsini zation, we allowed CEA to reach confluence, We then harvested CEA eith er as primary, secondary, or tertiary cultures, We detected mouse fibr oblasts using fluorescence activated cell sorting (FAGS) with a monocl onal antibody specific for mouse major histocompatibility (MHC) antige ns, We detected mouse MHC class II antigens by performing Western immu noblotting with another mouse MHC-specific monoclonal antibody, By FAG S we identified mouse fibroblasts in 100, 75, and 62.5% of primary, se condary, and tertiary passage CEAs, respectively. Similarly by immunob lotting we found mouse MHC class II antigen in 100, 80, and 66.7% of p rimary, secondary, and tertiary CEAs. These results demonstrate that x enogeneic fibroblast feeder layers capable of generating immunogenic t ransplantation antigens persist in CEAs. The persistence of these cell s and their antigen expression may contribute to CEA loss.