Huo-Luo-Xiao-Ling Dan modulates antigen-directed immune response in adjuvant-induced inflammation

Ethnopharmacological relevance: HLXL is a traditional Chinese medicine that has long been used in folk medicine for the treatment of chronic inflammatory diseases. However, the precise immunological mechanisms by which HLXL mediates its anti-inflammatory activity are not fully defined. Aim of the study: To determine the effects of HLXL on antigen-specific immune parameters in adjuvant-induced inflammation model in the Lewis rat. Materials and methods: Rats were fed daily with either HLXL (2.3 g/kg) or vehicle (water) beginning 3 days before subcutaneous injection of heat-killed Mycobacterium tuberculosis H37Ra (Mtb), and then continued for another 6 days. After 9 days of Mtb injection, the draining lymph node cells were tested for T cell proliferative and cytokine responses against mycobacterial heat-shock protein 65 (Bhsp65). Moreover, sera were tested for anti-Bhsp65 antibodies and nitric oxide (NO). Results: HLXL-treated rats showed reduced T cell proliferative response to Bhsp65 compared to control rats. Furthermore, HLXL suppressed IL-17 response but enhanced IL-10 response without much effect on IFN-γ. HLXL treatment also reduced the levels of anti-Bhsp65 antibodies but not that of NO. Conclusions: HLXL feeding modulated both the cellular and the humoral immune response to Bhsp65 favoring an anti-inflammatory milieu for the suppression of adjuvant-induced inflammation.