Carl M, Dasch G A
J Immunol. 1986 Apr 1;136(7):2654-61.
An in vitro culture and assay system was used to determine whether cytotoxic lymphocytes are generated in humans after rickettsial infection. Peripheral blood mononuclear cells (PBMC) were obtained from six individuals with serologic evidence of prior infection with typhus group rickettsiae and from six nonimmune individuals. After PBMC from immune individuals were stimulated in vitro for 7 days with rickettsial antigen, they were capable of lysing typhus group rickettsia-infected, autologous phytohemagglutinin (PHA)-induced blasts, but not uninfected PHA-blasts. No cytotoxic effector cells were generated when either PBMC from immune individuals were placed in culture for 7 days without antigenic stimulation, or when PBMC from nonimmune individuals were stimulated in vitro with antigen for 7 days. Freshly isolated PBMC from immune donors were also unable to lyse typhus group rickettsia-infected autologous PHA-blasts or an autologous rickettsia-infected lymphoblastoid cell line (LCL). Neither supernatants from antigen-stimulated cultures of PBMC from immune donors nor recombinant human interferon-gamma were capable of significantly lysing typhus group rickettsia-infected PHA blasts by this assay. Populations of cytotoxic effector cells depleted of OKT3, OKT4, or OKT8-positive cells by treatment with the respective monoclonal antibodies and complement were assayed for their cytotoxic capacity. The results suggest that the cytotoxic effector cell population is predominantly OKT3 and OKT8-positive, but OKT4-negative. Positive selection with the use of a fluorescence-activated cell sorter also suggested that most of the cytotoxic effector cells are OKT8-positive. PBMC from immune donors after in vitro stimulation with rickettsial antigen were capable of significantly lysing infected autologous LCL or infected HLA-mismatched LCL as compared with the respective uninfected controls. In addition, PBMC from either immune donors or nonimmune donors after stimulation in vitro for 7 days with media containing purified lymphokines were capable of significantly lysing autologous infected LCL as compared with the uninfected autologous control. We conclude that lysis of cells infected with typhus group rickettsiae is mediated by a lymphokine-activated killer.
采用体外培养和检测系统来确定立克次体感染后人体是否会产生细胞毒性淋巴细胞。从6名有斑疹伤寒群立克次体既往感染血清学证据的个体以及6名无免疫力的个体获取外周血单个核细胞（PBMC）。来自免疫个体的PBMC在体外用立克次体抗原刺激7天后，能够裂解斑疹伤寒群立克次体感染的、自体植物血凝素（PHA）诱导的母细胞，但不能裂解未感染的PHA母细胞。当来自免疫个体的PBMC在无抗原刺激的情况下培养7天，或者当来自无免疫力个体的PBMC在体外用抗原刺激7天时，均未产生细胞毒性效应细胞。来自免疫供体的新鲜分离的PBMC也无法裂解斑疹伤寒群立克次体感染的自体PHA母细胞或自体立克次体感染的淋巴母细胞样细胞系（LCL）。通过该检测，来自免疫供体的PBMC抗原刺激培养上清液和重组人干扰素-γ均不能显著裂解斑疹伤寒群立克次体感染的PHA母细胞。用相应的单克隆抗体和补体处理耗尽OKT3、OKT4或OKT8阳性细胞的细胞毒性效应细胞群体，检测其细胞毒性能力。结果表明，细胞毒性效应细胞群体主要为OKT3和OKT8阳性，但OKT4阴性。使用荧光激活细胞分选仪进行阳性选择也表明，大多数细胞毒性效应细胞为OKT8阳性。与各自未感染的对照相比，来自免疫供体的PBMC在体外用立克次体抗原刺激后，能够显著裂解感染的自体LCL或感染的HLA不匹配LCL。此外，与未感染的自体对照相比，来自免疫供体或无免疫力供体的PBMC在体外用含纯化淋巴因子的培养基刺激7天后，能够显著裂解自体感染的LCL。我们得出结论，斑疹伤寒群立克次体感染细胞的裂解是由淋巴因子激活的杀伤细胞介导的。
