Hines S A, Kanaly S T, Byrne B A, Palmer G H
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040, USA.
Vet Microbiol. 1997 Jun 16;56(3-4):177-85. doi: 10.1016/s0378-1135(97)00086-2.
Rhodococcal pneumonia is an important, life threatening disease of foals and immunosuppressed humans. Increased knowledge of the mechanisms of protective immunity are required in order to develop an effective immunoprophylaxis strategy for horses and immunotherapeutic regiments for people. Both humoral and cellular components of the immune system may be involved in immune clearance of R. equi. The susceptibility of foals less than 4-6 months of age is postulated to reflect waning maternal antibody, and passive transfer of hyperimmune plasma can provide protection on endemic farms. However, effective clearance is likely to require appropriate cellular responses, including the secretion of cytokines. In murine models, both CD4+ and CD8+ T lymphocytes can reduce bacterial counts in the lung. CD4+ cells appear to be both required and sufficient, and IFN-gamma is a primary mediator. Clearance appears to be a type 1 immune response while type 2 responses may lead to a failure to clear and lesion development. It remains to be determined how the cellular immunity experiments reported in mice relate to horses and humans. Likewise, the role of specific R. equi antigens in protective immunity has not been determined.
马红球菌肺炎是一种重要的、可危及马驹及免疫抑制人群生命的疾病。为了开发针对马匹的有效免疫预防策略以及针对人类的免疫治疗方案，需要更多关于保护性免疫机制的知识。免疫系统的体液和细胞成分都可能参与马红球菌的免疫清除。据推测，4至6月龄以下马驹的易感性反映了母源抗体的衰减，而超免疫血浆的被动转移可在地方病流行的养殖场提供保护。然而，有效的清除可能需要适当的细胞反应，包括细胞因子的分泌。在小鼠模型中，CD4+和CD8+ T淋巴细胞都可减少肺部的细菌数量。CD4+细胞似乎既是必需的也是足够的，而γ干扰素是主要介质。清除似乎是一种1型免疫反应，而2型反应可能导致清除失败和病变发展。小鼠细胞免疫实验与马和人类的关系仍有待确定。同样，马红球菌特定抗原在保护性免疫中的作用尚未确定。
