COMPARISON OF THE ABILITIES OF MHC-COMPATIBLE BONE NARROW CELLS AND LYMPH-NODE CELLS TO INDUCE TOLERANCE OF SKIN ALLOGRAFTS IN RATS

A comparison has been made of the abilities of bone marrow cells and l ymph node cells to induce tolerance of skin when inoculated into neona tal rats known to differ only with regard to non-MHC incompatibilities , including putative skin-specific (Skn) antigens. Each recipient rece ived 50x10(6) cells, and tolerance was confirmed by the permanent acce ptance of donor-strain neonatal heart tissue transplanted to the pinna of the ear. In 5 of the 8 MHC-compatible strain combinations tested, BMC were significantly more effective than LNC in inducing tolerance o f skin, whereas in one situation LNC proved more efficient. Although t he results are in accord with the occurrence of Skn antigens in rats, it appears that at least some of the antigens involved must also be ex pressed by BMC or LNC, but not equally by both of these tissues. The r esults also provide evidence that in rats, as in mice, the MHC can pla y a major role in determining the response to, and/or the immunogenici ty of, Skn antigens.