Department of Pathogenic Biology, Guangzhou Medical College, Guangzhou, Guangdong, 510182, China.
Parasitol Res. 2013 Mar;112(3):1255-60. doi: 10.1007/s00436-012-3259-1. Epub 2013 Jan 16.
The immune responses of Angiostrongylus cantonensis infection are closely relevant to the host's self-protection and the nematode's pathogenesis. In the present study, BALB/c mice were randomly divided into uninfected control group, infection group 1, and infection group 2. The infection group 1 and infection group 2 were infected with 20 and 40 third-stage larvae of A. cantonensis per mouse, respectively. The splenocytes from the mice were collected and cultured on the 19th and 25th days post-infection; the subtypes of T cells in splenocytes were detected by flow cytometry with fluorescence staining method, and the cytokines in cultured supernatants of splenocytes were assayed by the method of ELISA. The specific IgG and IgE antibodies in sera of the mice were periodically detected by ELISA. The results showed that the percentages of CD4(+) and CD4(+) IL-4(+) T cells in splenocytes of infected mice were much higher (P < 0.05) than those in control mice; however, the percentages of CD4(+) IL-17(+) and CD4(+) IFN-γ(+) T cell were much lower(P < 0.01) after the infection. The levels of CD8(+) T cells in infected mice also rose, but differences between control mice and infected mice were not significant. In comparison with control mice, the concentration of IL-4 in the cultured supernatants of splenocytes in infected mice increased significantly (P < 0.05), but that of IL-17 decreased significantly (P < 0.01). In addition, the number of larvae infected and days after infection may influence levels of the T cell subtypes and the cytokines in spleen, too (P > 0.05). On humoral immunity, the levels of specific IgG antibodies in sera rose a bit at the fifth day post-infection, and reached a peak at the 20th day post-infection; the specific IgE antibodies gradually heightened during first 10 days post-infection; then, it showed a downward trend during the 15th to 25th days post-infection. It is evident that the percentages of CD4(+) T lymphocytes of spleen in the mice infected with A. cantonensis markedly increase and polarize to Th2 phenotypes, and the function of Th17 cells is inhibited. In addition, the elevation of specific IgG antibodies in sera of the infected mice is more significant than that of specific IgE antibodies.
广州管圆线虫感染的免疫反应与宿主的自我保护和线虫的发病机制密切相关。本研究将 BALB/c 小鼠随机分为未感染对照组、感染组 1 和感染组 2。感染组 1 和感染组 2 分别感染 20 和 40 条广州管圆线虫第三期幼虫/只。于感染后第 19 天和第 25 天收集小鼠脾细胞进行培养；采用流式细胞术荧光染色法检测脾细胞 T 细胞亚群，采用 ELISA 法检测脾细胞培养上清液中细胞因子的水平。定期采用 ELISA 法检测小鼠血清中特异性 IgG 和 IgE 抗体。结果显示，感染组小鼠脾细胞中 CD4(+)和 CD4(+)IL-4(+)T 细胞的百分比明显高于对照组（P<0.05）；但感染后 CD4(+)IL-17(+)和 CD4(+)IFN-γ(+)T 细胞的百分比明显降低（P<0.01）。感染组小鼠 CD8(+)T 细胞水平也升高，但与对照组相比差异无统计学意义。与对照组相比，感染组小鼠脾细胞培养上清液中 IL-4 浓度明显升高（P<0.05），而 IL-17 浓度明显降低（P<0.01）。此外，感染幼虫数量和感染后天数也可能影响脾内 T 细胞亚群和细胞因子的水平（P>0.05）。在体液免疫方面，血清中特异性 IgG 抗体水平在感染后第 5 天略有升高，第 20 天达到高峰；特异性 IgE 抗体在感染后前 10 天逐渐升高；然后在感染后第 15 天至第 25 天呈下降趋势。由此可见，感染广州管圆线虫的小鼠脾内 CD4(+)T 淋巴细胞百分比明显升高并向 Th2 表型极化，Th17 细胞功能受到抑制。此外，感染小鼠血清中特异性 IgG 抗体的升高比特异性 IgE 抗体更为显著。
