Rejection of bone marrow cell allografts by natural killer cell subsets: 5E6+ cell specificity for Hh‐1 determinant 2 shared by H‐2d and H‐2f

Abstract

The 5E6 antigen, defined by anti‐5E6 mAb, is expressed on one‐half of murine natural killer (NK) cells, and we have previously demonstrated (C. L. Sentman et al., J. Exp. Med. 1989. 170: 1991) that 5E6⁺ NK cells are necessary for the rejection of BALB/c (Hh‐1^d) but not C567BL/6 (Hh‐1^b) bone marrow cells (BMC). In experiments described here, we have characterized the specificity of 5E6⁺ and 5E6⁻ NK cell subsets for hemopoietic histocompatibility‐1 (Hh‐1) antigens. Prospective recipient mice were treated with anti‐5E6 mAb and challenged with BMC from a variety of donors. In addition, H‐2^d/Hh‐1^d C.B‐17 scid 5E6⁺ or 5E6⁻ NK cells were adoptively transferred into irradiated, NK cell‐depleted hosts and challenged with H‐2^b/Hh‐1^b BMC. The data indicate that the 5E6⁺ NK cells are necessary for the rejection of only those BMC that express the Hh‐1 determinant 2 shared by H‐2^d and H‐2^f haplotypes of strains BALB/c (d), A.Ca (f), and B10.M (f). No reactivity to other Hh‐1 antigens resides in the 5E6⁺ population. In contrast, the ability of NK cells to lyse H‐2^d or H‐2^b tumor cells was independent of 5E6 expression. These results suggest that the 5E6 molecule is likely to be important in the specific recognition and rejection of BMC that express Hh‐1 determinant 2, and is probably not involved in recognition of „tumor target cell structures”︁.