The number of CD/ lymphocytes subpopulation in the immune organs and tissues of CIAV-infected chicks decreased lower than CD8+ T cells. The results indicated that CIAV infection destroyed CD4+ T-cell subsets more serious than CDg+.

• CIAV感染雏鸡ND免疫后28天内，胸腺、法氏囊、脾脏等免疫器官的CD_4~+、CD_8~+T细胞和IgG、IgM、IgA抗体生成细胞数量及CD_4~+与CD_8~+T细胞比值，均明显低于未感染CIAV的ND免疫雏鸡，表明CIAV感染雏鸡免疫器官对ND疫苗的免疫应答机能下降。