4 serum samples were collected on diﬀerent days after primary immunization for NDV-speciﬁc antibody assay. As Table 2 shows, HI titers of the three experimental groups were 1 or 2 log2 higher than that of the normal saline control group. Among the three doses tested, the 2 mg group had HI titers about 1 log2 higher than those of the other two groups from day 17 after SLS treatment. To further investigate the enhancive eﬀect of SLS on anti- body response in vaccinated chickens, blood samples were collected on diﬀerent days after vaccination and CD4+/CD8+ T-cell ratios in PBMCs were measured by ﬂow cytometry. As Table 3 shows, all the three experimental groups had signiﬁcant higher (P < .05) CD4+/CD8+ T-cell ratios than that of the saline control group from day 31 after SLS treatment. Similar to the antibody response, the 2-mg group has slightly higher CD4+/CD8+ T-cell ratio than that of the other two experimental groups. 3.3. Inﬂuence of SLS on Chicken Immune Organs. On dif- ferent days after SLS treatment and NDV vaccination, the thymus, spleen, and bursa of Fabricius of each chicken were collected and weighted for organ index calculation. As Table 4 shows, the indices of the three representative immune organs of the three SLS dose groups had no signiﬁcant diﬀerences compared to that of the saline control group. 3.4. Anti-Immunosuppressive Eﬀect of SLS in Chickens. After treatment with SLS plus thiamphenicol, thiamphenicol, or normal saline for successive 3 days, all birds were immunized with LaSota NDV vaccine and their serum samples and PBMCs were collected for NDV-speciﬁc antibody titration and CD4+/CD8+ T-cell ratio determination. As Table 5 shows, HI titer of the SLS plus thiamphenicol-treated group was signiﬁcantly higher than that of the thiamphenicol- treated group from day 10 after SLS treatment, which was comparable to that of the saline control group. For the CD4+/CD8+ T-cell ratio, the SLS-plus-thiamphenicol-treated group had higher score than that of thiamphenicol-treated group from day 10, but signiﬁcant diﬀerences were found only from day 31 after SLS treatment (Table 6). 4. Discussions Traditional Chinese medicine (TCM) has been widely used for thousands of years, and Chinese scientists have unveiled that many recipes of TCM have played a role in helping to improve the immune system of humans and animals [13]. But it is also facing many challenges; especially, the active ingredients of the most herbs and the role of the active components are still unclear or indistinct. SLS is synthesized artiﬁcially by using sodium bisulﬁte and houttuynin and has been used in the clinic for many years. Recent research has revealed the adjuvant activity and the possible mechanism of SH [13–16]. Whether SLS, the analogue of SH, has a similar eﬀect still needed to be demonstrated. To this end, in this study the immunoadjuvant eﬀects of SLS were investigated in vitro and in vivo. The results showed that SLS with suitable dose could not only promote the Veterinary Medicine International proliferation of chicken PBMCs in vitro but also enhance the NDV-speciﬁc antibody response in chickens. The possible reason(s) for this could be due to the increase in chicken CD4+/CD8+ T-cell ratio, which indicates the shift of cellular immune response to humoral response [23], since no signiﬁcant diﬀerences in lymphoid organ development were found after SLS treatment. Whether this eﬀect occurs also for other vaccines needs further research. Thiamphenicol is a popular antibiotic, which is widely used for treatment of bacterial diseases in animals. However, like many other antibiotics, the antibiotic has overt side eﬀects including immunosuppression [24]. Interestingly, the data of this study showed that SLS could promote NDV-speciﬁc antibody response in thiamphenicol-treated chickens. Although the detailed mechanism(s) remains to be deﬁned, the experimental data warrant us to further investigate the feasibility of SLS to reverse humoral immuno- suppression in other antibiotic(s)-used chickens. This may further widen our knowledge about the role and utilization of TCM in the future. Acknowledgments This work was supported by Natural Science Foundation of Jiangsu Province, China (Grant no. BK2006085). The authors would like to give our thanks to all the staﬀ of the Testing Centre of Yangzhou University for their help with some experiments. References [1] J.-S. Chang, L.-C. Chiang, C.-C. Chen, L.-T. Liu, K.-C. Wang, and C.-C. Lin, “Atileukemic activity of Bidenspilosa l. var. minor (Blume) sherﬀ and houttuynia cordata thunb,” American Journal of Chinese Medicine, vol. 29, no. 2, pp. 303– 312, 2001. [2] Y.-Y. Chen, C.-M. Chen, P.-Y. Chao, T.-J. Chang, and J.-F. Liu, “Eﬀects of frying oil and Houttuynia cordata thunb on xenobiotic-metabolizing enzyme system of rodents,” World Journal of Gastroenterology, vol. 11, no. 3, pp. 389–392, 2005. [3] Y.-Y. Chen, J.-F. Liu, C.-M. Chen, P.-Y. Chao, and T.-J. Chang, “A study of the antioxidative and antimutagenic eﬀects of Houttuynia cordata Thunb. Using an oxidized frying oil-fed model,” Journal of Nutritional Science and Vitaminology, vol. 49, no. 5, pp. 327–333, 2003. [4] L.-C. Chiang, J.-S. Chang, C.-C. Chen, L.-T. Ng, and C.-C. Lin, “Anti-herpes simplex virus activity of Bidens pilosa and Houttuynia cordata,” American Journal of Chinese Medicine, vol. 31, no. 3, pp. 355–362, 2003. [5] K. Hayashi, M. Kamiya, and T. Hayashi, “Virucidal eﬀects of the steam distillate from Houttuynia cordata and its components on HSV-1, inﬂuenza virus, and HIV,” Planta Medica, vol. 61, no. 3, pp. 237–241, 1995. [6] Y. Hou and X. Zhang, “Antiphlogistic action of Houttuynia cordata injection in vitro and in mice,” Zhongguo Zhong Yao Za Zhi, vol. 15, no. 4, pp. 221–222, 1990 (Chinese). [7] S.-H. Hu and A.-F. Du, “Treatment of bovine mastitis with houttuynin sodium bisulphate,” Journal of Veterinary Medicine Series B, vol. 44, no. 6, pp. 365–370, 1997.