Hao Shan Shan, Zong Man Man, Zhang Ze, Cai Jia Xi, Zheng Yang, Feng Xiu Li, Wang Chen
Key Laboratory of Animal Microbiology of China's Ministry of Agriculture, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Protein Pept Lett. 2019;26(7):542-549. doi: 10.2174/0929866526666190405123932.
Bursa of Fabricius is the acknowledged central humoral immune organ. The bursal-derived peptides play the important roles on the immature B cell development and antibody production.
Here we explored the functions of the new isolated bursal hexapeptide and pentapeptide on the humoral, cellular immune response and antigen presentation to Avian Influenza Virus (AIV) vaccine in mice immunization.
The bursa extract samples were purified following RP HPLC method, and were analyzed with MS/MS to identify the amino acid sequences. Mice were twice subcutaneously injected with AIV inactivated vaccine plus with two new isolated bursal peptides at three dosages, respectively. On two weeks after the second immunization, sera samples were collected from the immunized mice to measure AIV-specific IgG antibody levels and HI antibody titers. Also, on 7th day after the second immunization, lymphocytes were isolated from the immunized mice to detect T cell subtype and lymphocyte viabilities, and the expressions of co-stimulatory molecule on dendritic cells in the immunized mice.
Two new bursal hexapeptide and pentapeptide with amino acid sequences KGNRVY and MPPTH were isolated, respectively. Our investigation proved the strong regulatory roles of bursal hexapeptide on AIV-specific IgG levels and HI antibody titers, and lymphocyte viabilities, and the significant increased T cells subpopulation and expressions of MHCII molecule on dendritic cells in the immunized mice. Moreover, our findings verified the significantly enhanced AIV-specific IgG antibody and HI titers, and the strong increased T cell subpopulation and expressions of CD40 molecule on dendritic cells in the mice immunized with AIV vaccine and bursal pentapeptide.
We isolated and identified two new hexapeptide and pentapeptide from bursa, and proved that these two bursal peptides effectively induced the AIV-specific antibody, T cell and antigen presentation immune responses, which provided an experimental basis for the further clinical application of the bursal derived active peptide on the vaccine improvement.
法氏囊是公认的中枢体液免疫器官。法氏囊衍生肽在未成熟B细胞发育和抗体产生中发挥重要作用。
在此，我们探讨了新分离的法氏囊六肽和五肽在小鼠免疫中对体液、细胞免疫反应以及禽流感病毒（AIV）疫苗抗原呈递的作用。
采用反相高效液相色谱法纯化法氏囊提取物样品，并用串联质谱法分析以鉴定氨基酸序列。小鼠分别皮下注射三次不同剂量的AIV灭活疫苗加两种新分离的法氏囊肽。第二次免疫后两周，从免疫小鼠中采集血清样本，检测AIV特异性IgG抗体水平和血凝抑制（HI）抗体效价。此外，在第二次免疫后第7天，从免疫小鼠中分离淋巴细胞，检测T细胞亚群和淋巴细胞活力，以及免疫小鼠树突状细胞上共刺激分子的表达。
分别分离出两种氨基酸序列为KGNRVY和MPPTH的新的法氏囊六肽和五肽。我们的研究证明了法氏囊六肽对AIV特异性IgG水平和HI抗体效价以及淋巴细胞活力具有强大的调节作用，并且显著增加了免疫小鼠中T细胞亚群以及树突状细胞上MHCII分子的表达。此外，我们的研究结果证实，在用AIV疫苗和法氏囊五肽免疫的小鼠中，AIV特异性IgG抗体和HI效价显著提高，T细胞亚群显著增加，树突状细胞上CD40分子的表达也显著增加。
我们从法氏囊中分离并鉴定了两种新的六肽和五肽，证明这两种法氏囊肽能有效诱导AIV特异性抗体、T细胞和抗原呈递免疫反应，为法氏囊衍生活性肽在疫苗改进方面的进一步临床应用提供了实验依据。
