Immunosuppression induced by talc granulomatosis in the rat.

Granulomatosis caused by four subcutaneous talc powder-suspension injections induced strong immunosuppression in rats. The disturbance included reduction of mononuclear white blood cell count in the peripheral blood, atrophy of the thymic cortex, spleen enlargement with predominance of red over the white pulp, increase in the number of lymph node germinal centres and a significant delay of the first-set and second-set allograft rejection. Neither phagocytic function of reticuloendothelial system nor erythrocyte count and humoral immune response were found to be altered.

The effectiveness of intravenously administered immune lymphoid cells against intraperitoneally growing tumor correlates with their homing in the recipients' lymphoid organs.

Intraperitoneally growing Ehrlich ascites tumor (EAT) was eradicated by both i.p. and i.

Allergy induced by Parietaria officinalis pollen in southern Croatia.

Pollen of Parietaria officinalis causes season-associated respiratory symptoms. In Southern Croatia (Yugoslavia) we found 65% patients with rhinitis and/or asthma to be allergic to this pollen. They showed positive cutaneous reactions and had specific IgE antibodies to the respective isolated allergen.

Incidence and growth of methylcholanthrene-induced tumors in mice with altered immunological status.

BALB/c mice were treated s.c. with 3-methylcholanthrene (MCA), and tumor incidence and growth were followed for 9 months.

Bone marrow-derived T lymphocytes responsible for allograft rejection.

Lethally irradiated mice reconstituted with syngeneic bone marrow cells were grafted with allogeneic skin grafts 6-7 weeks after irradiation and reconstitution. Mice with intact thymuses rejected the grafts whereas the mice thymectomized before irradiation and reconstitution did not. Thymectomized irradiated mice (TIR mice) reconstituted with bone marrow cells from donors immune to the allografts rejected the grafts.

Interference of anti-tumor and immunosuppressive effects of cyclophosphamide in tumor-bearing rats. Analysis of factors determining resistance or susceptibility to a subsequent tumor challenge.

Adult rats were given 10(5) or 10(6) Yoshida ascites sarcoma (YAS) cells IP and were treated with cyclophosphamide (CY) given IP in single doses of 20 mg/kg or 100 mg/kg, 2 or 5 days after YAS inoculation. Both the curative effect of CY and subsequent resistance to tumor challenge in rats that survived depended on the dose of injected tumor cells and on the dose and time of administration of CY. These three factors determined whether the host's immune response to tumor antigens would develop and contribute to the overall anti-tumor effects of the chemotherapy.

Failure of parental T cells to restore T-cell deficient F1 mice.

The ability of normal, parental type T cells to initiate an immune response and to generate memory T cells in T-cell deficient F1 mice was investigated using two types of F1 recipients: Congenitally athymic (nude) mice and thymectomized, lethally irradiated, syngeneic bone marrow reconstituted (TIR) mice. In contrast to normal syngeneic T cells, normal parental type T cells elicited neither immune response nor memory T cells in F1 T-cell deficient mice. Parental T cells were ineffective even when obtained from chimeric donors tolerant to the second parental type transplantation antigens and normal, parental T cells did not counteract the restorative activity of F1 T cells in F1 T-cell-deficient recipients.

Involvement of Mhc loci in immune responses that are not Ir-gene-controlled.

Twenty-nine randomly chosen, soluble antigens, many of them highly complex, were used to immunize mice of two strains, C3H and B10.RIII. Lymph node cells from the immunized mice were restimulated in vitro with the priming antigens and the proliferative responses of the cells was determined.

Cooperation of murine F T and parental B lymphocytes in rejection of a xenogeneic tumour: adaptive differentiation of B lymphocytes?

The primary humoral immune response to rat Yoshida ascites sarcoma (YAS) grown in mice was used to study thymus-dependent (T) and bone marrow-derived (B) lymphocyte cooperation. It was shown that B6D2F1 T lymphocytes that do not cooperate with parental B lymphocytes enabled parental B lymphocytes from B6 leads to B6D2F1 radiation chimaeras to reject the tumour. However, when the bone marrow cells from B6 leads to B6D2F1 chimaeras were used to reconstitute parental B6 mice, these B6 leads to B6D2F1 leads to B6 mice lost their tolerance to D2 transplantation antigens, and their B lymphocytes were not able to cooperate with B6D2F1 T lymphocytes.

Immunological recovery of thymectomized and sham-thymectomized lethally irradiated mice reconstituted with syngeneic bone marrow cells.

Immunological functions of lethally irradiated mice reconstituted with syngeneic bone marrow cells recover after 5--6 weeks. In mice that had been thymectomized before irradiation and reconstitution, T-cell function is deficient but the B-cell function is preserved.