Immunomodulatory Activity of Polysaccharide-Protein Complex of Longan (Dimocarpus longan Lour.) Pulp

The immunomodulatory function of longan pulp polysaccharide-protein complex (LP3) was investigated in immunosuppressed mice models. Compared with the model control, peroral administration of 100 mgkg(−1)d(−1) LP3 could significantly increase/enhance antibody production against chicken red blood cell (CRBC), concanavalin A (ConA)-induced splenocyte proliferation, macrophage phagocytosis, NK cell cytotoxicity against YAC-1 lymphoma cell, and interferon-gamma (INF-γ) and interleukin-2 (IL-2) secretion in serum (P < 0.05). The immunomodulatory effects, except for those on splenocytes and macrophages (P > 0.05), were also observed in mice administered with 50 or 200 mgkg(−1)d(−1) LP3 (P < 0.05). The beneficial effects of 50–200 mgkg(−1)d(−1) LP3 were comparable to those of 50 mgkg(−1)d(−1) ganoderan. The strong immunomodulatory activity of LP3 confirmed its good potential as an immunotherapeutic adjuvant.