Application of an intermediate concentration of cyclophosphamide does not specifically deplete regulatory T cells in a mouse experimental model

• Published in: Archives of biological sciences Vol. 75; no. 4; pp. 397 - 406
• Main Authors: Radulovic, Natasa, Pilipovic, Ivan, Stojanovic, Ivana
• Format: Journal Article
• Language: English
• Published: University of Belgrade, University of Novi Sad 2023
• Subjects: cyclophosphamide; immunosuppression; lymphocytes; mouse experimental model; regulatory t cells (tregs)
• ISSN: 0354-4664; 1821-4339
• DOI: 10.2298/ABS230715032R

Cyclophosphamide (CP) is a cytostatic, widely used to treat different carcinomas and autoimmune diseases. It is commonly used in experimental designs modeling immunosuppression in laboratory animals, with different approaches for CP treatment but without a consensus on the dose, timing, and route of administration. We aimed to establish if treatment with CP in C57BL/6 mice depletes regulatory T cells (Tregs). Tregs are a crucial component of the immune system that helps maintain immune tolerance and prevent excessive immune reactions. They are significant in autoimmune diseases, allergies, and immune-related therapies. CP was applied intraperitoneally (i.p.) twice in a 5-day interval in doses of 100 mg/ kg. Monitoring of Treg prevalence in peripheral blood after each treatment and in the spleen after the second treatment with CP revealed a drop in the number of Tregs after two doses of CP because of the decreased number of total lymphocytes but not as a specific response of the Tregs. The prevalence of Tregs in peripheral blood after CP treatment mirrored the change in Treg number in the spleen. CP treatment induced a decrease in the number of CD3+ cells in the spleen while increasing their proportion, indicating that CP affected the B lymphocyte population rather than T cells. Our results suggest that CP treatment cannot be used as a specific Treg-depleting agent in the C57BL/6 animal model.