One Health: From Chinese traditional medicine to immunomodulation using Astragalus polysaccharides in a model of infectious bursal disease virus in

Introduction: Astragalus membranaceus, var mongholicus a member of the pea family, has been used in traditional Chinese and native American medicine for thousands of years to decrease morbidity of viral infections. As part of research into the ways immune systems can be controlled, the specific application of astragalus polysaccharides (APS) on chicken’s erythrocyte immune adherence was investigated with application to peri‐vaccinational stress. Immunomodulation encompasses selective regulation of parts of the immune response. Cytokines or their antagonists, gene therapy and vaccination with designer adjuvants have all been proposed and antibiotics such as macrolides have been shown to have effects. Immune responses are complex and inter‐dependent with neurological, endocrine and gastro‐intestinal systems. Cost effective and practical short‐term immuno‐modulation to address specific challenges such as vaccinational stress (common in children and livestock) is still poorly understood. Materials and Methods: 240 Specific Pathogen Free (SPF) Leghorn chickens were randomly divided into four groups reared in isolated pens. Chickens tested negative for infectious bursal disease virus (IBDV) at 25 days old. Group 1 was treated with saline, Groups 2, 3 and 4 were inoculated with 0.3 ml IBDV suspension intranasally the next day. Groups 3 and 4 were also administered APS intramuscularly twice daily at 5 or 10 mg kg−1 (0.05–0.1 ml), respectively, until 31 days old. The erythrocyte‐C3b receptor rosette rate (E‐C3bRR) and erythrocyte‐C3b immune complex rosette rate (E‐ICRR) were measured at 25, 29, 32, 35 and 38 days old. Duncan’s multiple range tests were used to test significance between groups for E‐C3bRR and E‐ICRR and rank sum analysis was performed on morbidity and mortality. Results: IBDV significantly reduced E‐C3bRR and E‐ICRR of chickens compared with the control group (p < 0.05, respectively), while simultaneous administration of APS with IBDV maintained E‐C3bRR at similar levels to control group and increased E‐ICRR compared with control group and the group non‐treated with APS (p < 0.05). APS treatment also reduced the morbidity and mortality of chickens inoculated with IBDV (p < 0.05). Conclusion: APS can modulate aspects of the immune response as evidenced by the enhanced immune adherence of chicken erythrocyte complement receptor type 1. This provides an objective insight into the mechanism of action to correlate with clinical outcomes from traditional usage patterns in man and animals where it has been used to up‐regulate immune responses in the face of viral and peri‐vaccinational stress