Induction of oral tolerance in splenocyte recipients toward pretransplant recipient lymphocytes decreased skin collagen production.

Skin biopsies were performed on splenocyte recipients 52 days after transplantation. Skin collagen α1 mRNA content was determined by in situ hybridization of skin section with a mouse collagen α1(I) probe. Mice in experimental group A, fed with homogenates of splenocytes derived from recipient strain BALB/c mice, 7 days after transplantation, showed much less collagen α1 (I) gene expression (panel A). In contrast, control nontolerant recipients in groups B and C, fed after transplantation, with homogenates prepared from B10.D2 mouse splenocytes or BSA, respectively, showed significantly higher levels of collagen αI gene expression (panels B and C). (Original magnification ×10.)