Immunosuppressed Murine Model for Studies in Allergy: Evaluation of Immunosuppression Induced by Cyclophosphamide, Dexamethasone and Cyclosporin in Balb-C Mice

Immunosuppressed animals are important research models for studies in allergy, oncology, immunology, and infectious diseases. Immunosuppressive drugs have been experimentally used to obtain a state of immunodeficiency in mice. This investigation aimed to quantify the circulating T and B cells of mice treated with the immunosuppressive agents dexamethasone (Dx), cyclosporin (CsA) and cyclophosphamide (CY), as well as to observe the behaviour of lymphocytic populations in the spleen of these animals. Balb-C mice were divided into 4 groups: I - mice immunosuppressed with CY (75 mg/kg, twice a week, intraperitoneal route - ip); II - mice treated with Dx (5 mg/kg, daily, ip); III - mice which received CsA (10 mg/kg, 3 times a week, ip); and IV - control group. The animals were sacrificed at 7, 14 and 28 days after the beginning of the treatment. On those days blood samples were collected for counting the total peripheral blood leukocytes and T and B lymphocytes using flow cytometry with monoclonal antibodies to CD3 and CD19, respectively. Total leukocytes of mice treated with the three drugs in all days showed a significant decrease when compared to the results of the control group. The proportion of B and T lymphocytes from the treated animals also decreased significantly in all dates. Spleen sections revealed a severe decrease in the cellularity of the white pulp and the development of lymphocyte apoptosis in mice from groups I and II. The results showed that the proposed experimental models demonstrated to be suitable for studies of murine immunodeficiency.