Brown W C, Zhu D, Shkap V, McGuire T C, Blouin E F, Kocan K M, Palmer G H
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, Washington 99164, USA.
Infect Immun. 1998 Nov;66(11):5414-22. doi: 10.1128/IAI.66.11.5414-5422.1998.
Major surface proteins of Anaplasma marginale are vaccine candidates. We recently demonstrated that immunization of calves with outer membranes of the Florida strain of A. marginale resulted in protective immunity that correlated with a memory CD4(+) T-lymphocyte response specific for major surface protein 1 (MSP-1), MSP-2, and MSP-3 (W. C. Brown, V. Shkap, D. Zhu, T. C. McGuire, W. Tuo, T. F. McElwain, and G. H. Palmer, Infect. Immun. 66:5406-5413, 1998). As immunogens, these proteins have been shown to induce complete or partial protection against homologous challenge. To further define the T helper (Th) cell response to these and other A. marginale antigens and to determine conservation of Th cell epitopes among genetically distinct A. marginale strains, Th cell clones obtained prior to challenge from three immunized calves were characterized for antigen-specific responses. Nine distinct antigenic profiles were defined by 11 Th cell clones derived by stimulation with the Florida strain. Several clones responded to MSP-2, MSP-3, or both. All of these MSP-2- or MSP-3-specific clones and the majority of other clones that did not respond to MSPs recognized all bovine blood-passaged strains of A. marginale. These results demonstrate conservation of certain Th cell epitopes between MSP-2 and MSP-3 and show that Th cell epitopes in MSP-2, MSP-3, and undefined antigens are conserved among strains of A. marginale. Of seven clones that responded to the blood-passaged Virginia strain, two did not recognize antigen prepared from this strain cultured in tick cells, suggesting differences in the antigenic composition between these stages. Analysis of the cytokines expressed by the Th cells revealed that all clones expressed gamma interferon and tumor necrosis factor alpha, and most coexpressed interleukin-4. Our results provide a rationale for identifying Th cell epitopes conserved among different strains of A. marginale for inclusion in a nucleic acid or recombinant protein vaccine.
边缘无形体的主要表面蛋白是疫苗候选物。我们最近证明，用边缘无形体佛罗里达菌株的外膜免疫犊牛可产生保护性免疫，这与针对主要表面蛋白1（MSP-1）、MSP-2和MSP-3的记忆性CD4(+) T淋巴细胞反应相关（W.C.布朗、V.什卡普、D.朱、T.C.麦圭尔、W.托、T.F.麦克尔韦恩和G.H.帕尔默，《感染与免疫》66:5406 - 5413，1998年）。作为免疫原，这些蛋白已被证明可诱导针对同源攻击的完全或部分保护。为了进一步确定T辅助（Th）细胞对这些及其他边缘无形体抗原的反应，并确定Th细胞表位在基因上不同的边缘无形体菌株间的保守性，对三只免疫犊牛在攻毒前获得的Th细胞克隆进行了抗原特异性反应特征分析。通过用佛罗里达菌株刺激产生的11个Th细胞克隆定义了9种不同的抗原谱。几个克隆对MSP-2、MSP-3或两者都有反应。所有这些对MSP-2或MSP-3特异的克隆以及大多数对MSP无反应的其他克隆都识别所有边缘无形体的牛血液传代菌株。这些结果证明了MSP-2和MSP-3之间某些Th细胞表位的保守性，并表明MSP-2、MSP-3和未定义抗原中的Th细胞表位在边缘无形体菌株间是保守的。在对血液传代弗吉尼亚菌株有反应的7个克隆中，有2个不识别由在蜱细胞中培养的该菌株制备的抗原，这表明这些阶段之间抗原组成存在差异。对Th细胞表达的细胞因子分析显示，所有克隆都表达γ干扰素和肿瘤坏死因子α，且大多数同时表达白细胞介素-4。我们的结果为鉴定在不同边缘无形体菌株间保守的Th细胞表位以纳入核酸或重组蛋白疫苗提供了理论依据。
