A study of H-2 mutations in mice. V. Detection of mutations M505, Hzl and M506 in the host vs transplant reaction]

H-2 mutant/normal pairs of congenic mouse strains C57BL/6equilibriumB6.M505 (H-2Kbd), C57BL/6equilibriumB6.C(Hz1) (H-2Kba) and A.CAequilibriumA.CA(M506) (H-2fa) were studied in the graft versus host assay. All the three mutations were expressed in these tests as gain and loss of H-2 antigen. The data obtained confirm an earlier suggestion that the H-2K antigenic molecule bears antigenic determinants which could be detected by a variety of immunological techniques.     

Reciprocal influence of the graft vs. host reaction and pregnancy]

The graft versus host reaction (GVHR) was induced in mouse females-hybrids F1 (CBA X C57BL/6) by intravenous injection of suspension of the lymphoid cells of the spleen and of lymphoid nodes from C57BL/6 mouse females. Pregnancy resulted from interbreeding of the test females with syngenic males 1--5 days before, and 1--10, 10--20, 30--40 and more than 40 days after the moment of the lymphoid cells injection, aggravated the GVHR induced transplantation disease. At the same time the GVHR under these conditions decreased the percentage of pregnant animals and brought to child-bearing disfunction of the test animals (stillbirth, death of pregnant females, miscarriage). In some of the test mice aggravation of the GVHR was observed after delivery. Survival of the progeny decreased.     

Immunogenetic analysis of H-2 mutations. III. Genetic mapping and involvement in immune reactions of the H-2ka mutation.

Mutation M523 (H-2ka) occurred spontaneously in strain CBA/CaLacSto and was discovered during routine skin graft testing for genetic homogeneity. By linkage and complementation tests, the mutation was previously mapped in the K end of the H-2 complex. We demonstrate that the mutation occurred in the K region, without affecting the I region in the K end of the complex. The mutant antigens cause rejection of skin grafts, stimulate cells in mixed lymphocyte culture, and function as stimulators as well as targets in cell-mediated lymphocytotoxicity. Yet, they are serologically indistinguishable from the antigens of the original strain and do not induce formation of humoral antibodies upon immunization of the CBA strain. Together with the results obtained on testing of other H-2 mutants, the data strongly support the notion that classical H-2 antigens (i.e., products of the H-2K and H-2D loci) can function as lymphocyte-stimulating determinants, and that I-region differences are not required for the induction of strong cell-mediated lymphocytotoxicity.     

Diminution by vesicular stomatitis virus of acute graft vs host mortality in mice.

Preincubation of parental spleen cells with vesicular stomatitis virus (VSV) in vitro reduces their subsequent ability to cause lethal GVH disease in irradiated F₁ hybrid recipients. Antibody to VSV is needed to protect the irradiated mice against the virus. Protection is afforded even to the acute GVH induced by spleen cells presensitized to the other parent. No reduction of the late-occurring GVH mortality is obtained with VSV, even though this late GVH is mediated by T cells as it is completely abolished by pretreatment of BM with anti-Thy 1.2 + C. The results suggest that the known ability of VSV to replicate in activated T cells may be used selectively to inhibit certain unwanted immune reactions in vivo.     

Graft vs host reaction in reciprocal combinations of mouse strains differing by the H-2 complex of histocompatibility]

Intraperitoneal transplantation of 0.5 x 10(7), 1 x 10(7) or 2 x 10(7) spleen cells from the C57BL mice to newborn CBA recipients induced an acute form or runt disease which resulted in the death of 43%, 86% or 95% of the recipient mice, respectively, in the course of 2--3 weeks after the cell transfer. Preliminary immunization of C57BL donors with CBA isoantigens led to a marked enhancement, and immunization with foreign antigens (sheep red blood cells)--to weakening the reaction. In reverse combination of mouse strains the runt disease was 4--5 times less severe and no "preimmunization effect" occurred. In C57BL leads to CBA combination the reaction was accompanied by proliferation of pyroninophilic mononuclears and follicular destruction, while in the CBA leads to C57BL combination-by the retardation of their growth.     

Morphological changes in the late periods of life in mice born after the induction of the graft vs. host reaction in their mothers]

Histological changes were studied in various organs of 1--2-year-old mice born after induction of the graft-versus-host reaction in mothers. The lymphoid tissue showed predominant atrophic changes, and a number of mice (61.2%) developed amyloidosis in the spleen and liver. The lymphoid infiltrates were found in the liver, kidneys, lungs and heart. In some cases glomerulonephritis, vasculitis and liver distrophy were recognized. Lymphoid malignancies were recorded in 17.7% of cases, wherease neoplasms in the control mice of the same age were incident only in 4.1%. Some neoplasms could be transplanted to adult F1 mice. A cell-free extract inocualted into newborn mice did not produce tumours during observational period of 14 months.     

Study ofH-2 mutations in mice VI. M523, a newK end mutant

A newH-2 mutation was found in a mouse belonging to CBA/CaLacSto (H-2 ^k ) strain and designated 523, the proposed haplotype symbol for which isH-2 ^ka . The line CBA.M523 carries this mutation and is fully congenic with the parental strain, except for the mutant site 523. The mutation 523 is located within theK- end of theH-2 gene complex. Phenotypically, it causes prompt skin graft rejection and pronounced graft-versus-host activity in strain combination CBA/Sto⇄C-BA.M523. Attempts to produce active alloantisera in the same strain combination have so far been unsuccessful.     

Correlation of splenomegaly and blood picture changes in graft vs host reaction of the mouse]

The early phase of graft-versus-host-reaction is characterized by a rapid decline of lymphocytes in the peripheral blood, with a minimum between days 9 and 11, and return to normal until day 20 after spleen cell grafting. Erythrocytes and hematocrit do not change during this period. There is no causal correlation between splenomegaly and lymphopenia. Lymphopenia provides a criterium for experimental graft-versusu-host-reaction equivalent to the spleen-index.     

Immuno- and erythropoiesis in mice with graft vs host disease against a background of immunodeficiency

In BALB/c mice immunodeficiency was induced by the transfer of lymphocytes immune to alloantigen. This model is one of experimental models of AIDS. The work was aimed at the study of disturbances in the immuno--and erythropoiesis in immunodeficient mice. The state of erythropoiesis was evaluated by the level of level of hemoglobin, hematocrit and the content of reticulocytes in peripheral blood, by the number of erythroid bursitis-forming units and the percentage of erythrokaryocytes in the marrow, as well as by the number of colony-forming units in the spleen by days 5 and 8. The study revealed that in BALB/c mice hypoplastic anemia, accompanied by the decreased phagocytic activity of macrophages and the reduced production of interleukin 1 and tumor necrosis factor, developed on months 5-6 of the disease. Macrophagal dysfunction was supposed to be one of the causes of hypoplastic anemia in immunodeficient mice.     

Immunogeneic analysis of H-2 mutations. II. Cellular immunity to the H-2DA mutation.

The H-2da haplotype was derived from the H-2d haplotype by a mutation localized to the D end of the H-2 complex. Coculture of H-2d and H-2da spleen cells gives rise to bidirectional MLR. However, the H-2d anti-H-2da response is much stronger than that of H-2da anti-H-2d. Both haplotypes give rise to reciprocal CML. B10.D2(R103) strain spleen cells, which differ only at the D end of the H-2 complex from the H-2d haplotype, kill H-2da target cells in CML when sensitized to H-2d stimulators and vice versa. Therefore, both the mutant and strain of origin share a D end CML specificity. H-2d and H-2da reject skin grafts in both directions, although some H-2d grafts show prolonged acceptance on H-2da recipients. These data are consistent with a mutation in the D end of the H-2d haplotype resulting in gain-loss of an antigen(s) that gives rise to reciprocal MLR, CML, and skin graft rejection. Further, the mutant can be distinguished from the strain of origin on the basis of the strength of immune response in MLR.     

Impairment of host vs graft reaction in pregnant mice. I. Suppression of cytotoxic T cell generation in lymph nodes draining the uterus.

The fetus resulting from an allogenic (interstrain) mating represents a type of graft that is not rejected by the mother. Nevertheless, the maternal immune system seems to recognize and to react to the presence of the fetus in a number of ways. One such manifestation is significant enlargement of the lymph nodes that drain the uterus (DLN) of pregnant rodents. We have tested the DLN lymphocytes of mice for reactivity to paternal H-2 alloantigens after interstrain mating. The DLN lymphoid cells obtained from pregnant mice killed fewer newborn F1 recipients in a graft-vs-host mortality assay, and generated less cytotoxic T cell activity against paternal H-2 antigens both in vivo and in vitro. In vitro mixing experiments demonstrated the presence of a cell-associated suppressor activity in the DLN of pregnant mice. This suppressor proved resistant to treatment with mitomycin C, and appeared in the DLN early in pregnancy.     

Study of H-2 mutations in mice. IV. A comparison of the mutants M505 and Hz1 by skin grafting and serological techniques

The line B6.M505 is congenic with C57BL/6JY and carries a mutant form of theH-2 ^b haplotype designatedH-2 ^bd . The mutant site 505 was located by the F₁ tests in theK end of theH-2 gene complex. The M505 mice are histoincompatible with the B6.C(Hz1) line (haplotypeH-2 ^ba ) carrying another mutation in theK end ofH-2 ^b . Inability of M505 to complement Hz1 in tests with B6 skin grafting is considered as an evidence that the same gene was altered by both mutations. The gained H antigens of two mutants can cross-react in vivo as revealed by accelerated rejection of Hz1 skin grafts by B6 recipients presensitized with M505 spleen cells. The lost antigenic determinants are not identical as shown by accelerated rejection of B6 skin grafts by Hz1 hosts preimmunized with M505 spleen cells. Absorptions of the antiserum ASY-015, (d×a) anti-i, anti-H-2.33 with M505 spleen cells did not clear forH-2 ⁱ ,H-2 ^b andH-2 ^ba , and absorptions with Hz1 did not clear forH-2 ⁱ ,H-2 ^b , andH-2 ^bd . These results show that changes of histocompatibility determinants may be accompanied by loss of some haptenic determinants in the Hz1 and M505 mutations.     

Induction in vivo of specific T suppressors in mice of mutant lines H-2KbT

The differences in the generation of specific suppressor T cells (SSTC) against H-2Kb wild type were investigated in H-2Kbm1, H-2Kbm3 and H-2Kbm4 mutants. Anti-Kb SSTC were produced only by bm3 mutant and F1(BALB/c X bm3) hybrid. T-cell nature of SSTC of bm3 mutant was confirmed by anti-Thy 1.2 monoclonal antibodies described in the same study.