Ganta Roman Reddy, Peddireddi Lalitha, Seo Gwi-Moon, Dedonder Sarah Elizabeth, Cheng Chuanmin, Chapes Stephen Keith
Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506, USA.
Front Biosci (Landmark Ed). 2009 Jan 1;14(9):3259-73. doi: 10.2741/3449.
Several tick-transmitted Anaplasmataceae family rickettsiales of the genera Ehrlichia and Anaplasma have been discovered in recent years. Some species are classified as pathogens causing emerging diseases with growing health concern for people. They include human monocytic ehrlichiosis, human granulocytic ewingii ehrlichiosis and human granulocytic anaplasmosis which are caused by Ehrlichia chaffeensis, E. ewingii and Anaplasma phagocytophilum, respectively. Despite the complex cellular environments and defense systems of arthropod and vertebrate hosts, rickettsials have evolved strategies to evade host clearance and persist in both vertebrate and tick host environments. For example, E. chaffeensis growing in vertebrate macrophages has distinct patterns of global host cell-specific protein expression and differs considerably in morphology compared with its growth in tick cells. Immunological studies suggest that host cell-specific differences in Ehrlichia gene expression aid the pathogen, extending its survival. Bacteria from tick cells persist longer when injected into mice compared with mammalian macrophage-grown bacteria, and the host response is also significantly different. This review presents the current understanding of tick-Ehrlichia interactions and implications for future.
近年来，已发现几种由蜱传播的埃立克体属和无形体属的无形体科立克次氏体。一些物种被归类为病原体，引发了人们日益关注的新兴疾病。它们包括人单核细胞埃立克体病、人粒细胞尤因埃立克体病和人粒细胞无形体病，分别由恰菲埃立克体、尤因埃立克体和嗜吞噬细胞无形体引起。尽管节肢动物和脊椎动物宿主具有复杂的细胞环境和防御系统，但立克次氏体已经进化出逃避宿主清除并在脊椎动物和蜱宿主环境中持续存在的策略。例如，在脊椎动物巨噬细胞中生长的恰菲埃立克体具有独特的全宿主细胞特异性蛋白质表达模式，并且与其在蜱细胞中的生长相比，形态有很大差异。免疫学研究表明，埃立克体基因表达中的宿主细胞特异性差异有助于病原体延长其生存期。与在哺乳动物巨噬细胞中生长的细菌相比，将来自蜱细胞的细菌注射到小鼠体内后存活时间更长，并且宿主反应也有显著差异。本综述介绍了目前对蜱 - 埃立克体相互作用的理解及其对未来的影响。
