表达H3N2亚型猪流感病毒血凝素蛋白的重组腺病毒在猪体内的免疫试验

Elicitation of protective immune responses by a recombinant adenovirus expressing hemagglutinin of H3N2 SIV in swine

摘要:

摘要:【目的】本研究旨在评价表达H3N2亚型猪流感病毒血凝素蛋白的重组腺病毒在猪体内的免疫效果。【方法】以10-8 TCID50、2×10-8 TCID50和4×10-8 TCID50的剂量经肌肉注射接种后2到6周每周检测血凝抑制（HI）抗体；比较肌肉注射、滴鼻、灌胃三种接种途径对仔猪免疫效果的影响，并通过攻毒保护试验进一步考察重组腺病毒rAd-HA-GFP在猪体内的免疫效力。【结果】以不同的剂量分别经肌肉注射免疫后， HI抗体水平与接种剂量呈正相关。三种接种途径均能刺激仔猪产生特异性抗体，肌肉注射组的HI抗体要高于其他两组，差异显著（P<0.01）。通过滴鼻和肌注注射方式进行攻毒后，阴性对照组仔猪在攻毒2d后出现体温升高、打喷嚏、咳嗽、流鼻液、精神沉郁、体重减轻等症状；而各免疫组仔猪未观察到明显的临床症状，各免疫组的病毒分离率也明显低于阴性对照组。【结论】重组腺病毒rAd-HA-GFP诱导的HI抗体达到1:320可以有效抵抗H3N2亚型猪流感病毒的侵袭，可以作为候选疫苗株。

Abstract:

Abstract: [Objective] To evaluate the immunity of the adenovirus recombinant rAd-HA-GFP encoding an H3N2 swine influenza virus hemagglutinin. [Methods] Thee groups of 6-week-old pigs (5 pigs per group) were vaccinated intramuscularly with the recombinant, one group was immunized with 10-8 TCID50 recombinant adenovirus rAd-HA-GFP, the other groups were vaccinated with 2×10-8 TCID50 and 4×10-8 TCID50. A control groups (5 pigs) were vaccinated with recombinant adenovirus rAd-GFP. virus-specific hemagglutination-inhibition(HI) antibody was detected by 2-6 weeks post vaccination. Compared the difference of vaccinated intramuscularly, intragastric administration and intranasal inoculation，thee groups of different HI antibody pigs and one control group were challenged with a virulent H3N2 field virus. [Results] The results showed that pigs in the groups given higher immunizing dose were developed higher levels HI antibody. All of vaccinated intramuscularly, intragastric administration and intranasal inoculation could produce HI antibody, but the titer of vaccinated intramuscularly was higher significantly(P<0.01).Three groups of pigs(5 pigs per group) which HI titers were 1:80，1:160，1:320 respectively were challenged with a virulent H3N2 field virus, include the negative control group. The immunization efficacy was evaluated by clinical signs,the rate of virus isolation and HI titer. It suggested that immunological response induced by rAd-HA-GFP could resist attack of SIV effectively. [Conclusion] The adenovirus vaccines rAd-HA-GFP are efficacious for SIV and have the additional advantage over commercial vaccines that suckling piglets have no pre-existing maternally-derived antibody to block early life vaccination.