Analysis of deficient colony-forming performance of bone marrow cells in non-syngeneic cell milieu--the impact of non-immune interactions on the behaviour of pluripotent stem cells and the role of H-2 gene products

Acute rejection of murine bone marrow allografts by natural killer cells and T cells. Differences in kinetics and target antigens recognized

Lethally irradiated C.B-17 +/+, C.B-17 scid/scid (severe combined immunodeficiency, SCID), BALB/c-nu/nu (nude), and C57BL/6 (B6) mice were challenged with H-2-homozygous or H-2-heterozygous totally allogeneic bone marrow cell (BMC) grafts. Some of the irradiated mice were immunized simultaneously with large numbers of irradiated marrow and spleen cells syngeneic with the viable BMC transferred. Irradiated SCID and nude mice, devoid of T cells but with normal NK cell function, were able to reject H-2-homozygous BMC grafts within 4 d. However, they were unable to reject H-2-heterozygous BMC allografts by 7 d even if they were immunized. B6 and C.B-17 +/+ mice were able to reject H-2 heterozygous BMC allografts by 7-8 d, but not as early as 4 d, if they were immunized. The rejection of H-2-homozygous BMC on day 4 was inhibited by administration of anti-NK-1.1 antibodies, but not by anti-Lyt-2 antibodies. Conversely, the rejection of H-2-heterozygous allogeneic BMC on day 8 was prevented by anti-Lyt-2 but not by anti-NK-1.1 antibodies. The data indicate that both NK cells and Lyt-2+ T cells can mediate rejection of allogeneic BMC acutely, even after exposure of mice to lethal doses of ionizing irradiation. NK cells appear to recognize Hemopoietic histocompatibility (Hh) antigens on H-2 homozygous stem cells. The inability of SCID and nude mice to reject H-2 heterozygous totally allogeneic BMC indicate that NK cells do not survey donor marrow cells for self H-2 antigens and reject those cells that express nonself H-2 antigens. The T cells presumably recognize conventional H-2 antigens (probably class I) under these conditions.

Involvement of the K and I regions of the H-2 complex in resistance to hemopoietic allografts

Irradiated (H-2b X H-2k)F1 and (H-2b X H-2d)F1 recipients strongly resist the growth of H-2b parental bone marrow cells and do not resist marrow grafts from non-H-2b parents such as C3H and BALB/c. This phenomenon of hybrid resistance has been shown to be under genetic control of the H-2D-linked loci and was interpreted by Cudkowicz (9) as due to the existence of H-2D-linked recessive hemopoietic histocompatibility genes. To check whether the H-2D-linked loci are solely responsible for the fate of bone marrow allografts, we measured the strength of resistance of irradiated (B6 X C3H)F1 and (B6 X BALB/c)F1 recipients toward bone marrow grafts from a set of H-2 recombinant and F1 hybrid donors carrying either the H-2b, H-2d, and H-2k alleles. We found that growth of all H-2b grafts was resisted, although to different degrees. Resistance was minimal when donors shared with the input strain of a corresponding F1 hybrid the H-2K and H-2I regions, or when both F1 donors and F1 recipients formed identical unique hybrid Ia molecules. In addition, H-2b grafts were resisted by congenic, H-2D-identical, H-2K-and H-2I-incompatible recipients. The fate of grafts from H-2Dd donors seemed to depend on the incompatibility of the combinatorial determinant Ia.22. If both donor and recipient expressed such a determinant (either in the cis or in the transposition), or if neither could form such a determinant, grafts were not resisted. The H-2Dk allele is not the main or only factor that confers on the C3H parental bone marrow cells the ability to grow unresisted in (B6 X C3H)F1 recipients. Grafts from congenic C3H.OH donors, carrying the same H-2Dk alleles and differing in the left part of the H-2 complex, were resisted by the F1 recipients. We conclude that both class I (K and D) and class II (I-A and I-E) major histocompatibility complex genes, rather than hypothetical hemopoietic histocompatibility genes control hemopoietic resistance. To reconcile codominant inheritance of classic H-2 antigens with the apparent recessive inheritance of hybrid resistance, we assume that there exist parental determinants that are not formed in some F1 hybrids due to preferential association of either Ia alpha chains with allogeneic beta chains or of class I antigens with allogeneic or hybrid class II restriction elements.

Genetic resistance of CBA and A mice to transplanted lymphoid and hemopoietic cells of CBA.M523 mutants and their F1 hybrids

(CBA X M523)F1, (A X M523)F1 and M523 lymphocytes grafted into lethally irradiated CBA or A mice temporarily lose their capacity to respond to test antigens (SRBC, Vi-antigen, S. typhi). Immunoresponsiveness of F1 cells is affected to a lesser degree in lethally irradiated M523 mice. Depression of response is absent in the CBA leads to F1 combination, in the syngeneic combination and in CBA mice whch have received transplanted cells from F1 hybrids which do not share the M523 mutation. The number of hemopoietic (CBA X M523)F1 colonies was also reduced in CBA mice. Resistance of CBA mice to lymphoid (CBA X M523)F1 cells develops 18 days after birth. It can be reduced by additional recipient preirradiation or preinoculation with (CBA X M523)F1 spleen cells. The abrogated resistance can be partially restored by CBA spleen cells. The activity of (CBA X M523)F1 lymphocytes passaged through CBA spleen is restored in syngeneic F1 secondary recipients but inhibited again in the CBA secondary recipients. These results are consistent with the suggestion that resistance of lethally irradiated CBA mice to hemopoietic and lymphoid (CBA X M523)F1 cells is mediated by immunologically competent, radioresistant recipient cells rapidly reacting to transplantation antigens coded by the mutant H-2Kka allele. These cells temporarily suppress the functional activity of transplanted cells but do not eliminate them.