猪圆环病毒2型感染裸鼠及BALB/c小鼠的研究

Experimental infection with porcine circovirus type 2 in nude mice and BALB/c mice

用猪圆环病毒2型(PCV2)经腹腔注射BALB/c小鼠及裸鼠各15只,每隔2周1次,共感染3次。BALB/c小鼠初次、再次感染后均未出现明显的临床症状,仅有2只小鼠出现病理变化;从血清中可检测到PCV2核酸及其ORF2抗体;同时淋巴细胞增殖反应显著增强,NK和CTL细胞杀伤率显著升高;CD4+、CD8+、CD3+T淋巴细胞及CD19+B淋巴细胞数量显著减少。裸鼠也未出现明显的临床症状,从血清中可检测到PCV2核酸,但未检测到PCV2 ORF2抗体;除NK细胞杀伤率显著升高外,其余免疫学指标无显著改变。结果表明,BALB/c小鼠比裸鼠对PCV2易感,各项免疫学指标变化与PCV2感染猪一致,但不表现临床症状,仅个别BALB/c小鼠出现病理变化,说明BALB/c小鼠对PCV2不如猪易感。

Nude mice and BALB/c mice of fifteen each group were inoculated with porcine circovirus type 2 （PCV2） intraperitoneally three times at intervals of two weeks respectively. No obvious clinical symptoms were observed and PCV2 DNA was detected both in nude mice and BLAB/c mice. Two BALB/c mice manifested a light microscopic lesion. Compared with those in the control group, the antibody titers, splenocyte activity,cytotoxic activity of NK cells and CTLs of BALB/c mice in the treatment group increased significantly and the numbers of CD4^＋ ,CD8^＋ ,CD3^＋T cells and CD19^＋ B cells decreased obviously. The nude mice in the experiment group were not significantly different in antibodies titers, splenocyte activity and CTL activity,as well as the numbers of CD4^＋ ,CD8^＋ ,CD3^＋ T cells and CD19^＋ B cells from those in the control group,but NK activity was inclined. Although no clinical signs were observed,2 of 15 BALB/c mice had a microscopic lesion and the numbers of T,B lymphocyte subgroups in the BALB/c mice declined. The above-mentioned immunological indexes in the infected BALB/c mice were compatible With those in swine with PMWS. In conclusion, BALB/c mice were less susceptible to PCV2 than swine and more susceptible than nude mice.