将16头断奶仔猪随机分成两大组即直接感染组和间接感染组,再将每大组用ELISA测抗体水平并排序分成两小组,即高抗体水平的4头为高起始抗体组,低抗体4头为低起始抗体组。直接感染组注射PCV2攻毒后再注射钥匙孔血蓝蛋白(KLH)刺激,间接感染组不注射与直接感染组混养。Q-PCR检测血清中病毒拷贝数,血常规检测全血中淋巴细胞数,定时称量体质量,屠宰后采样制作HE染色病理切片。结果,HE染色病理切片和临床分析显示感染猪只表现断奶仔猪多系统衰竭综合征(PMWS)症状;直接感染组和间接感染组攻毒后抗体水平持续降低,且分别在攻毒后20、30d降到相对最低值。直接感染组在攻毒后4d检测到抗原,攻毒后7d低起始抗体组病毒拷贝数显著高于高起始抗体组,间接感染组分别在攻毒后4、7d检测出抗原,攻毒后24、29d低起始抗体组抗原显著高于高起始抗体组;两组中外周血淋巴细胞数量在攻毒后减少,攻毒期间两大组中低起始抗体组和高起始抗体组体质量无差异。结果表明,PCV2+KLH能够复制出PMWS症状;PCV2母源抗体的半衰期为15d左右;低起始抗体组更容易感染病毒;攻毒后起始母源抗体的高低对断奶仔猪增重差异不明显。 Sixteen weaned piglets were randomly divided into two groups, direct infection group and indirect infection group, and then each group was divided into two groups according to the ELISA antibody level, that is, 4 high antibody groups were high-start antibody group and low Antibody 4 heads for the low initial antibody group. Direct infection group injected PCV2 challenge and then injected keyhole limpet hemocyanin (KLH) stimulation, indirect infection group was not injected and direct infection group polyculture. The number of virus copies in serum was detected by Q-PCR, the number of lymphocytes in whole blood was measured by blood routine, the body weight was weighed at regular intervals, and HE-stained sections were made after slaughtering. Results HE staining and clinical analysis showed that infected pigs showed the symptoms of multiple system failure syndrome (PMWS) in weanling piglets. The antibody levels of the infected and indirect infection groups continued to decrease after challenge, Drop to a relatively low value. In the direct infection group, the antigen was detected 4 days after challenge, and the copy number of the low initial antibody group at 7 days after challenge was significantly higher than that of the high initial antibody group. The indirect infection group detected the antigens at 4 and 7 days after challenge, respectively After 24 and 29 days, the number of low initial antibody group antigen was significantly higher than that of the high initial antibody group; the number of peripheral blood lymphocytes in both groups decreased after challenge, and the low initial antibody group and high initial antibody No difference in group quality. The results showed that PCV2 + KLH could replicate the symptoms of PMWS. The half-life of PCV2 maternal antibody was about 15 days. The low-antibody group was more susceptible to virus infection. The weight of starting maternal antibody after challenge was not significantly different .