Murphy J W
Department of Botany-Microbiology, University of Oklahoma, Norman 73019.
Infect Immun. 1989 Jul;57(7):1946-52. doi: 10.1128/iai.57.7.1946-1952.1989.
To assess the effects of cryptococcal antigen-induced immunosuppression on a Cryptococcus neoformans infection, CBA/J mice were injected intravenously with saline or suppressive doses of cryptococcal antigen (CneF) at weekly intervals and were then infected with viable C. neoformans cells. By the second week after infection, the cryptococcal antigen-injected mice had suppressed anticryptococcal delayed-type hypersensitivity (DTH) responses compared with the responses of the saline-treated, infected control mice. In addition, the immunosuppressed mice had higher numbers of cryptococcal CFU cultured from their lungs, livers, spleens, lymph nodes, and brains than did the control animals. A direct correlation of suppression of the anticryptococcal DTH response and reduced clearance of cryptococci from tissues was also observed after mice were given a single intravenous injection of CneF and infected. To determine whether or not the cryptococcal antigen was specifically reducing the clearance of C. neoformans or had a more generalized effect, mice were injected with saline or suppressive doses of CneF, infected with Listeria monocytogenes, and then followed daily for 7 days for the clearance of L. monocytogenes from spleens and on day 7 for DTH reactivity to Listeria antigen. There were no differences between the saline- and CneF-treated mice with respect to anti-Listeria DTH responses or clearance of L. monocytogenes from spleens, indicating that CneF was not altering natural resistance mechanisms responsible for early clearance of L. monocytogenes, nor was the CneF influencing the induction of the acquired immune response which was responsible for the late clearance of the bacteria. Together, these data indicate that the specific suppression of this cell-mediated immune response induced by cryptococcal antigen reduces the ability of the animals to eliminate the homologous organism (C. neoformans) but not a heterologous infectious agent, such as L. monocytogenes.
为评估隐球菌抗原诱导的免疫抑制对新型隐球菌感染的影响，每周一次给CBA/J小鼠静脉注射生理盐水或抑制剂量的隐球菌抗原（CneF），然后用活的新型隐球菌细胞进行感染。感染后第二周，与注射生理盐水、受感染的对照小鼠相比，注射隐球菌抗原的小鼠抗隐球菌迟发型超敏反应（DTH）受到抑制。此外，免疫抑制小鼠肺、肝、脾、淋巴结和脑中培养出的隐球菌CFU数量比对照动物多。在给小鼠单次静脉注射CneF并感染后，还观察到抗隐球菌DTH反应的抑制与组织中隐球菌清除率降低之间存在直接相关性。为确定隐球菌抗原是特异性降低新型隐球菌的清除率还是具有更广泛的作用，给小鼠注射生理盐水或抑制剂量的CneF，用单核细胞增生李斯特菌进行感染，然后每天跟踪7天以观察脾脏中单核细胞增生李斯特菌的清除情况，并在第7天观察对李斯特菌抗原的DTH反应性。在抗李斯特菌DTH反应或脾脏中单核细胞增生李斯特菌的清除方面，注射生理盐水和CneF的小鼠之间没有差异，这表明CneF没有改变负责早期清除单核细胞增生李斯特菌的天然抵抗机制，CneF也没有影响负责后期清除该细菌的获得性免疫反应的诱导。总之，这些数据表明，隐球菌抗原诱导的这种细胞介导免疫反应的特异性抑制降低了动物清除同源生物体（新型隐球菌）的能力，但不影响清除异源感染因子，如单核细胞增生李斯特菌的能力。
