Investigation on Immunomodulatory Activity of Calf Spleen Extractive Injection in Cyclophosphamide‐induced Immunosuppressed Mice and Underlying Mechanisms

Calf spleen extractive injection (CSEI), extracted from the spleen of healthy cows (within 24 h of birth), is a small peptides enriched extraction while the ratio between peptide and ribose is 76 ± 15.2 mg/μg. CSEI is usually used as an ancillary agent to assist cancer patients with immune dysfunction. The present study aims to evaluate the immunomodulatory activity of CSEI in cyclophosphamide (CTX)‐induced mice model of immunosuppression and its underlying mechanisms. During the experiment, thymosin ɑ1 (0.16 mg/kg) was served as the positive control drug. In CTX‐induced immunosuppressed mice, CSEI significantly increased bodyweights and spleen indexes, and upgraded the natural killer activity together with lymphocytes proliferation. CSEI regulated the production of IgG and IgA, and the levels of IL‐2, 6, 10, 12 and IFN‐ɑ, γ and TNF‐ɑ in serum of CTX‐induced immunosuppressed mice. Furthermore, CSEI markedly downregulated nuclear factor kappa‐B (NF‐κB) expression which was controlled by IKKβ. Taken together, CSEI effectively improved immune function in CTX‐induced immunosuppression related to NF‐κB signalling pathway via regulating the production of immunoglobulins, interleukins and some inflammatory factors.