被动免疫预防犊牛轮状病毒感染的研究

目的 轮状病毒灭活疫苗免疫孕牛后，研究产下犊牛通过母源抗体获得的被动免疫在预防牛轮状病毒感染中的作用。方法 孕牛产前2月和1月分别接种轮状病毒灭活疫苗，检测产牛后乳汁和犊牛血样中BRV特异性IgG、IgA及中和抗体滴度。犊牛21日龄时口服2mL10^4,59 TCID50／ml的牛轮状病毒，观察犊牛腹泻及排毒情况。结果 免疫组乳清和犊牛血清中产生了高水平的牛轮状病毒特异性IgG、IgA及中和抗体，与对照组差异极显著（P〈0．01）；攻毒后，对照组6头犊牛全部发生腹泻，免疫组6头中有1头腹泻，发病的潜伏期及发病率差异显著。结论 被动免疫可显著提高犊牛血清中牛轮状病毒特异性抗体水平，使犊牛获得一定的免疫保护力抵抗轮状病毒的感染。

Passive antibody immunization against bovine rotavirus infection

Cows were immunized with bovine rotavirus vaccine and then the effect of passive antibody from colostrum and serum on the immunity against bovine rotavirus infection was investigated, in which cows were immunized at two and one month before calving, and IgG, IgA and neutralizing rotavirus antibody in colostrum or serum were determined. A virulent bovine rotavirus was given orally to the calves at 21 days after birth, and the infection rate after challenge were compared. It was demonstrated that the titer of the anti-rotavirus antibody in colostrum and serum in the vaccinated group of cows was significantly increased compared with that of the control group (P<0.01), however, 6 calves born from control cows and one calve born from vaccinated cows developed diarrhea after challenge. The incubation periods and the infection rates appeared to be quite different between these two groups of cows(P<0.01). It is apparent that the passive antibody immunization can elevate significantly the level of the specific antibodies against bovine rotavirus infection and can prevent infection after rotavirus challenge.