Brown S J
Department of Biology, Loyola Marymount University, Los Angeles, CA 90045.
Vet Parasitol. 1988 May;28(3):245-59. doi: 10.1016/0304-4017(88)90112-4.
Feeding by adult Amblyomma americanum ticks induced a level of immunity in rabbits to subsequent tick feeding that resulted in a significant decrease in tick feeding success and fecundity. Histological analysis of tick feeding sites in hosts expressing resistance revealed a predominant eosinophil response, with weak basophil and neutrophil infiltrates. While the basophil was never the dominant granulocyte at the tick feeding sites in resistant hosts, this cell exhibited the greatest increase in density (tenfold) over levels observed in hosts experiencing their first infestation; eosinophils and neutrophils exhibited increases of five- and twofold, respectively. Serum from animals that expressed resistance was tested for the presence of anti-tick antibodies to tick-derived salivary gland substances (SGA) by Western blotting. Western blot analysis of female-derived SGA compared to male-derived SGA, using the Avidin/Biotin technique, resulted in the identification of approximately 25 proteins from the female preparation, but only seven from the male. The use of 125I labeled protein-A as the probe for anti-tick antibody in Western blot analysis resulted in fewer recognized proteins. Serum from rabbits immunized with A. americanum-derived SGA emulsified with complete (CFA) Freund's adjuvant recognized most of the proteins identified by active serum, whereas serum from animals immunized with SGA in incomplete (IFA) Freund's adjuvant did not. Furthermore, both sera recognized a multiplicity of proteins from extracts of larval A. americanum Dermacentor variabilis and Boophilus microplus ticks, suggesting the presence of common antigens between these distantly related ticks. The results from this study demonstrate that rabbits acquire a strong immunity to A. americanum ticks characterized by the production of antibody. Furthermore, ticks secrete a number of substances into rabbits during feeding, as seen by Western blot analysis but only three may be crucial to the induction of host immunity; proteins at 41, 40 and 39 kDa. The purified anti-tick antibody will be used for subsequent isolation and characterization of crucial antigens.
成年美洲钝眼蜱的取食可使兔子对后续蜱虫取食产生一定程度的免疫力，从而导致蜱虫取食成功率和繁殖力显著下降。对表现出抗性的宿主中蜱虫取食部位进行组织学分析，发现主要是嗜酸性粒细胞反应，伴有较弱的嗜碱性粒细胞和中性粒细胞浸润。虽然在抗性宿主的蜱虫取食部位，嗜碱性粒细胞从未成为主要的粒细胞，但该细胞的密度相较于首次感染的宿主增加最为显著（十倍）；嗜酸性粒细胞和中性粒细胞的密度分别增加了五倍和两倍。通过蛋白质印迹法检测表现出抗性的动物血清中是否存在针对蜱虫唾液腺物质（SGA）的抗蜱抗体。使用抗生物素蛋白/生物素技术，对雌性来源的SGA与雄性来源的SGA进行蛋白质印迹分析，结果从雌性样本中鉴定出约25种蛋白质，而从雄性样本中仅鉴定出7种。在蛋白质印迹分析中使用¹²⁵I标记的蛋白A作为抗蜱抗体的探针，可识别的蛋白质数量较少。用完全弗氏佐剂乳化的美洲钝眼蜱来源的SGA免疫的兔子血清可识别活性血清鉴定出的大多数蛋白质，而用不完全弗氏佐剂免疫的动物血清则不能。此外，两种血清均可识别美洲钝眼蜱、变异革蜱和微小牛蜱幼虫提取物中的多种蛋白质，这表明这些亲缘关系较远的蜱虫之间存在共同抗原。本研究结果表明，兔子可通过产生抗体获得针对美洲钝眼蜱的强大免疫力。此外，如蛋白质印迹分析所示，蜱虫在取食过程中会向兔子分泌多种物质，但其中只有三种可能对诱导宿主免疫至关重要；分子量分别为41 kDa、40 kDa和39 kDa的蛋白质。纯化的抗蜱抗体将用于后续关键抗原的分离和鉴定。
