不同品系小鼠对卡氏肺孢子虫的易感性及其免疫反应的研究

目的　探讨不同品系小鼠对卡氏肺孢子虫 (P.c)的易感性及其免疫反应。　方法　以接触传播方式使BAL B/ c和 C5 7BL / 6小鼠 (各 15只 )感染 P.c。观察小鼠与传染源接触 4、5、6 wk后肺内虫数、支气管肺泡灌洗液中CD4 + T细胞和 CD8+ T细胞及血清 Ig G水平的变化。　结果　与传染源接触 4 wk,小鼠肺内均可检出 P.c,之后 ,BAL B/ c小鼠虫数继续增高 ,5 wk末达高峰。4 wk时 C5 7BL/ 6小鼠虫数无明显变化 ,5 wk时显著少于 BAL B/ c小鼠。两组小鼠支气管肺泡灌洗液内 CD4 + CD6 2 low T细胞和 CD8+ CD6 2 low T细胞数明显增多 ,血清 Ig G抗体水平显著上升。6 wk小鼠肺内 P.c均转阴。　结论　 BAL B/ c比 C5 7BL / 6小鼠更易感染 P.c。 BAL B/ c和 C5 7BL / 6小鼠感染 P.c后5 wk可产生有效的细胞和体液免疫反应并清除肺内感染的 P.c

Susceptibility and Immune Responses to Pneumocystis carinii Infection in Different Strains of Mice by Contagious Transmission

Objective To explore the susceptibility of different strains of mice to P.carinii infection and the host immune response to the organism. . Methods. C57BL/6 and BALB/c strains of mice (15 each) were exposed to SCID mice infected with P.carinii by co-housing. Observations were made on the number of parasites in the lungs, level of CD4+ T cell and CD8+ T cell in BALF, and serum IgG at 4, 5 and 6 wk after contagion.. Results . The number of P.carinii grew in the lungs of BALB/c mice was found much greater than those in C57BL/6 mice. A few number of P.carinii cysts were detected in the lungs of both strains of mice by 4 wk after co-housing, the number of cysts increased at 5 wk in the lungs of BALB/c mice but not in that of C57BL/6 mice. P.carinii-specific IgG in the sera and high level of CD62.{low.} CD4-and CD8-positve T cells in the lungs were found at 5 wk. The parasites were cleared from the lungs at 6 wk in all infected mice, shortly after acquired immune response was initiated. . Conclusion . BALB/c mice are more susceptible to P.carinii than the C57BL/6 mice by natural transmission, and all the immunocompetent mice can clear the infection of P.carinii by cellular and humoral immune responses.