重组鸡痘病毒表达的鸡IL-1β、IL-2和髓细胞生长因子对新城疫La Sota疫苗免疫效果影响

Adjuvant effect of chicken IL-1β,IL-2 and myelomonocytic growth factor(MGF)expressed by recombinant fowlpox viruses on newcastal disease La Sota strain

为研究在新城疫LaSota疫苗免疫不全的情况下,重组鸡痘病毒(rFPV)表达的鸡白细胞介素1β(IL-1β)、白细胞介素2(IL-2)和髓细胞生长因子(MGF)是否具有免疫增强作用。10日龄SPF鸡随机分成8组(I～VIII),每组18只,每只接种1个半数保护剂量(PD50)的LaSota疫苗,同时免疫不同剂量的表达鸡IL-1β、IL-2或cMGF的rFPV(rFPV-IL-1β、IL-2、cMGF)。结果:rFPV表达的IL-1β、IL-2或cMGF可以消除鸡痘病毒在免疫早期对雏鸡体重增长的影响;一定剂量的IL-1β和IL-2可使鸡脾脏中CD4+T细胞和CD8+T细胞的总体水平提高;免疫21d后用新城疫的F48E8强毒经肌肉攻毒,一定剂量的IL-1β和IL-2(I和III组)能提高LaSota疫苗的免疫保护率,而cMGF却没有表现出这种作用。本研究表明rFPV表达的IL-1β和IL-2在一定的剂量下可以增强LaSota疫苗的免疫效果,具有免疫增强作用。

Three chicken cytokines（IL-1β, IL-2, cMGF）expressed by recombinant flowpox viruses （rFPVs） were evaluated for their adjuvant effect on a sub-optimal dose of newcastal disease La Sota strain. Groups of 10-day-old SPF chickens were given the La Sota virus （IPD50/chicken） plus a rFPV expressing chicken IL-1β, IL-2 or cMGF, respectively（103 and 105 PFU/chicken） or parental control virus （105 PFU/chicken） via the neck by subcutaneous inoculation, then were challenged with F48E8 virus （10^5ELD50/chicken） 21 days after immunizations. IL-1β, IL-2 or cMGF expressed by rFPV significantly protected against body weight loss induced by rFPV at 7 days post immunizations. Flow cytometric analysis of spleen lymphocytes showed chickens that received the rFPVs （10^3pFU/chicken） expressing chicken IL-1βor IL-2 had significantly increased CD4^＋ cells at 7 day or CD8^＋T cells at 14 day after immunizations compared to those vaccinated with parental virus. After lethal intra muscular challenge, chickens immunized with IL-1βor IL-2-expressing virus （10^3 PFU/chicken） were significantly protected against death compared with chickens received parental virus（10^5 PFU/chicken）. Taken together, our results suggest that a certain amount of IL-1β or IL-2 as adjuvant expressed by rFPVs can promote cell-mediate immunity and improve the protection efficacy of the La Sota vaccine.