Evidence for two types of non-specific suppressor cells activated by the graft-versus-host reaction in mice

In vitro experiments were carried out to investigate the immunosuppressive efect of different populations of spleen cells obtained from animal experiencing a graft-versus-host reaction (GVHR). To induce the GVHR, parental lymphoid cells were injected into adult F1 hybrid mice. GVHR-activated spleen cells (GVH-sc) taken at different times post-GVHR induction were separated into adherent and non-adherent fractions and treated with anti-theta serum plus complement. The different types of GVH-SC were added to either parental (donor-type) of F1 (host-type) normal spleen cells and cultured with sheep erythrocytes in a modified Marbrook chamber. It was found that both adherent and non-adherent 10-day GVH-SC significantly inhibited the plaque-forming cell response of F1 normal spleen cells but not that of parental normal spleen cells. Significant suppression of the parental response was observed following the addition of 15-day GVH-SC or anti-theta treated adherent and non-adherent 7-day GVH-SC. The results suggest that the non-specific immunosuppressive effect of GVH-SC is mediated by GVHR-activated macrophages and B lymphocytes found in the anti-theta treated adherent and non-adherent fractions of the GVH-SC suspensions respectively.

Subpopulations of mouse T lymphocytes. II. Suppression of graft-vs.-host reactions by naturally proliferating splenic T cells

The immunological role of a naturally proliferating subpopulation of splenic T cells was investigated using the graft-vs.-host (GvH) reaction on the mouse. Normal parental spleen cells, purified splenic T cells or lymph node cells were pulse-treated for one hour in vitro with tritiated thymidine of high specific activity ([3H]dThd, "thymidine suicide"). The treatment specifically and selectively kills proliferating cells which are actively synthesizing DNA, i.e. cells in S phase. Following treatment, the cells were transferred to F1 recipients and the GvH reaction measured by the splenomegaly assay. The results showed that the GvH effector cells in the donor spleen and lymph node are nonproliferating T cells. Furthermore, donor spleen cells treated with [3H]dThd consistently had enhanced GvH reactivity when compared to the controls, while the phytohemagglutinin response of these same treated cell suspensions was significantly inhibited. When purified splenic T cells were used, treatment with [3H]dThd also caused an increase in the GvH reaction, showing that a T cell population was being affected by the cycleactive agent. These results indicated that some naturally proliferating T cells have suppressor functions, and their specific inactivation allows nonproliferating effector T cells to mount a more vigourous GvH reaction.

Adoptive immunochemotherapy of a transplantable AKR leukemia (K36)

Adoptive immunotherapy of a transplantable AKR leukemia (K36) was carried out as an adjunct to cytoxan chemotherapy using normal allogeneic H-2-incompatible spleen cells as well as sensitized H-2-matched allogeneic spleen cells. A significant therapeutic effect was obtained with cytoxan and allogeneic C57BL/6 splenocytes, demonstrating the potential use of the graft-versus-host reaction. Utilizing specific adoptive immunochemotherapy, a maximum effect was found with splenocytes from allogeneic but H-2-compatible CBA/J mice immunized against an allogeneic Gross-virus-induced lymphoma (E female G2). This therapeutic effect was most likely the result of prior sensitization of donor lymphocytes to common virus-associated tumor antigens.

Effect of aflatoxin on the humoral and cell-mediated immune systems of the chicken

Chickens fed 2.5 microgram of aflatoxin/g of diet from 2 to 4 weeks of age or from hatching to 4 weeks were deficient in cell-mediated immunity, as measured at 4 weeks of age by the graft-versus-host reaction. Delayed-type hypersensitive skin reactions to tuberculin were also reduced in chickens given dietary aflatoxin from hatching to 7 weeks of age. Humoral immunity, as measured by the ability of 4-week-old chicks to produce natural agglutinins to rabbit red blood cells, was not significantly altered by dietary aflatoxin. A significant decrease in concentrations of serum immunoglobulins (Ig) IgG and IgA, but no IgM, however, did occur in chicks given dietary aflatoxin from hatching to 4 weeks or between 2 and 4 weeks of age. Aflatoxin consumption from 0 to 2 weeks of age produced no marked effect on either cell-mediated or humoral immunity in 4-week-old chicks.

[Graft-versus-host reaction following granulocyte transfusion from a normal donor (author's transl)]

Graft-versus-Host disease following the transfusion of leukocytes from normal donor occured during remission-reinduction therapy in a 5 years old girl with acute lymphocytic leukemia. The clinical picture consisting of rash, diarrhea and somnolence was congruent with the diagnosis. Graft-versus-Host disease was confirmed by histology of skin biopsy and exclusion of other causes. The child survived the disease. We recommend the irradiation of leukocyte concentrates before transfusion.

Bone marrow transplantation between mixed leukocyte culture reactive siblings

Bone marrow transplantation from an HLA identical MLC reactive sibling has been performed in a patient with acute myelogenous leukemia resistant to drug treatment. Prompt engraftment was documented; however, the patient died of septicemia 34 days after transplant. Clinical manifestation of graft vs. host reaction was mild but was moderately strong expressed at autopsy tissue samples. Recurrence of persistence of leukemia was found at the time of death.

Analysis of the major histocompatibility complex in Syrian hamsters. II. Linkage studies

The genetic control of the histocompatibility antigens that induce strong alloreactions in Syrian hamsters was examined. Genetic studies revealed that the alloantigens involved in skin graft rejection, graft-versus-host reactions, and mixed lymphocyte reactions are under dominant single gene control and that these genetic loci are closely linked. These data suggest that this strong histocompatibility locus (i) may represent the major histocompatibility complex equivalent in this species, and this locus or group of loci has been called Hm-1. In addition, studies concerning the genetic control of the immune response to bovine serum albumin suggest that the high response is under dominant, single gene control; however, this gene is not linked to Hm-1.

Immunopathology

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Mice bearing the ob/ob mutation have impaired immunity

The obese mutant mouse C57BL/6J ob/ob showed impaired ability to reject skin grafts or react to a contact-sensitising agent in comparison with littermate controls (either +/ob or +/+). Ability of spleen cells from mice bearing the ob/ob mutation to produce a graft-versus-host reaction in C57BL/6J X DBA/2J F1 hybrid mice was not impaired.

Experimental models for prevention of graft-versus-host reaction in bone marrow transfution. III. Reversible and irreversible differentiation of lymphocytes destined for cytotoxicity to effector cells for splenomegaly

When lymphoid cells were obtained from AKR donors 12 h after a treatment with C57BL/L cells in complete Freund's adjuvant and transferred to (AKR X C57BL/6) F1 mice, splenomegaly in F1 recipients was augmented but cytotoxicity was suppressed. The suppression of cytotoxicity was antigen-specific. When cell transfer was carried out at stages as early as 3 or 6 h after the treatment of donors, cytotoxicity was enhanced but splenomegaly was suppressed. Irreversible deviation of immune response from the generation of cytotoxicity to the development of splenomegaly appears to occur within 12 h after such a treatment of donors.

Methotrexate and citrovorum factor after histoincompatible allogeneic bone marrow transplants in dogs

Methotrexate (MTX) followed by citrovorum factor (CVF) rescue was evaluated for its effectiveness in reducing graft-versus-host disease (GVHD) in lethally irradiated dogs transplanted with bone marrow from unrelated histoincompatible donors. Animals were given no immunosuppressive therapy (group A) or a combined regimen of MTX and CVF (group AMC). These two groups were compared with a group of animals transplanted earlier given MTX alone (group AM). Ainmals in the AMC group lived significantly longer than the A group (p less than 0.05). Engraftment rate, hematopoietic recovery and incidence of GVHD were similar in all three groups. Incidence of early deaths was significant in the AM group (p less than 0.05). It is concluded that MTX combined with CVF increases survival and is an effective posttransplantation immunosuppressive regimen with minimal toxicity.