Walker D H, Henderson F W
Infect Immun. 1978 Apr;20(1):221-7. doi: 10.1128/iai.20.1.221-227.1978.
The role of the immune response in the pathogenesis of Rickettsia rickettsii infection in guinea pigs was investigated by immunosuppression, using antilymphocyte serum. Twenty guinea pigs were inoculated with R. rickettsii, Sheila Smith strain, on day 0. Fifteen animals received antilymphocyte serum on days --1, 0, 2, 4, and 6. Five animals received normal rabbit serum on the same schedule. At necropsy, specimens were collected for histological examination, rickettsial immunofluorescence, rickettsial titration, and antirickettsial antibody titration. All normal rabbit serum recipients and 12 of 15 antilymphocyte serum recipients developed typical disease. Comparison of animals in terminal stages of disease revealed the same clinical course and gross lesions, but differing rickettsial burden and cellular response. Immunosuppressed animals had higher titers of splenic rickettsiae and greater numbers of immunofluorescent rickettsiae. Thus, although antibody was undetectable in both groups, there appeared to be an inhibition of antirickettsial immunity. Microscopic vasculitis was similar quantitatively, but differed qualitatively, with immunocompetent animals having the typical monouclear/lymphocytic inflammation and immunosuppressed animals having neutrophilic predominance. This study demonstrates that immunopathological mechanisms are not necessary for the pathogenesis of experimental Rocky Mountain spotted fever. The rickettsiae themselves seem capable of causing cellular and tissue damage.
通过使用抗淋巴细胞血清进行免疫抑制，研究了免疫反应在豚鼠感染立氏立克次体发病机制中的作用。20只豚鼠在第0天接种了立氏立克次体希拉·史密斯菌株。15只动物在第-1、0、2、4和6天接受抗淋巴细胞血清。5只动物按相同时间表接受正常兔血清。尸检时，收集标本进行组织学检查、立克次体免疫荧光、立克次体滴定和抗立克次体抗体滴定。所有接受正常兔血清的动物以及15只接受抗淋巴细胞血清的动物中有12只出现了典型疾病。对处于疾病末期的动物进行比较发现，临床病程和大体病变相同，但立克次体负荷和细胞反应不同。免疫抑制的动物脾脏立克次体滴度更高，免疫荧光立克次体数量更多。因此，尽管两组均未检测到抗体，但似乎存在抗立克次体免疫的抑制。显微镜下血管炎在数量上相似，但在质量上不同，免疫活性动物具有典型的单核/淋巴细胞炎症，而免疫抑制动物以中性粒细胞为主。本研究表明，免疫病理机制对于实验性落基山斑疹热的发病机制并非必要。立克次体本身似乎能够引起细胞和组织损伤。
