猪圆环病毒2型感染裸鼠及BALB/c小鼠的研究

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。

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

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.