Nayar J K, Knight J W, Vickery A C
J Med Entomol. 1989 May;26(3):159-66. doi: 10.1093/jmedent/26.3.159.
Intracellular melanization responses to developing larvae of Brugia species (B. malayi (Buckley), B. pahangi (Buckley and Edeson), and B. patei (Buckley, Nelson, and Heisch] in the thoracic muscle fibers of eight strains of Anopheles quadrimaculatus Say were first observed 48 to 72 h after an infective blood meal. Three to 4 d later, large numbers of melanized first-stage larvae were found within the thoracic muscle fibers. These intracellular responses were in addition to the extracellular responses to microfilariae and microfilarial sheaths of B. pahangi in the abdominal hemocoel of An. quadrimaculatus described in literature. Simultaneously, normal development of larvae of the three Brugia species also was observed in all eight strains of An. quadrimaculatus. Comparisons of melanized first-stage larvae and normally developing larvae of the three Brugia species in the thoracic muscle fibers of the eight strains of An. quadrimaculatus showed that there were distinct variations in numbers of melanized and developing larvae and percentage of females with melanized and developing larvae in different strains. Numbers of melanized first-stage larvae reflected the extent of refractoriness of An. quadrimaculatus strains. Fully melanized larvae showed no abnormalities in parasite organelles, indicating that refractoriness is due to an enhanced ability of the host to recognize the living parasite. Further comparison among the strains suggested that the mutants, Yellow Larvae and Vero Beach Colony were significantly more susceptible, and Red Stripe was the most refractory to all three Brugia species. Thus, the gene(s) controlling susceptibility and refractoriness to all three Brugia species probably occurs on the same autosomal chromosome as the mutations in these strains. The significance of intracellular melanization of filarial larvae is discussed with reference to the melanization responses to different parasites in other mosquitoes.
在感染性血餐后48至72小时首次观察到，八株四斑按蚊Say的胸肌纤维对马来布鲁线虫（Buckley）、彭亨布鲁线虫（Buckley和Edeson）及帕氏布鲁线虫（Buckley、Nelson和Heisch）发育幼虫的细胞内黑化反应。三至四天后，在胸肌纤维内发现大量黑化的第一期幼虫。这些细胞内反应是文献中描述的四斑按蚊腹部血腔对彭亨布鲁线虫微丝蚴和微丝蚴鞘的细胞外反应之外的反应。同时，在所有八株四斑按蚊中也观察到三种布鲁线虫幼虫的正常发育。对八株四斑按蚊胸肌纤维中三种布鲁线虫黑化的第一期幼虫和正常发育幼虫的比较表明，不同菌株中黑化和发育幼虫的数量以及带有黑化和发育幼虫的雌蚊百分比存在明显差异。黑化的第一期幼虫数量反映了四斑按蚊菌株的抗性程度。完全黑化的幼虫在寄生虫细胞器方面没有异常，表明抗性是由于宿主识别活寄生虫的能力增强。菌株之间的进一步比较表明，突变体黄幼虫和维罗海滩群体对所有三种布鲁线虫明显更易感，而红条纹对所有三种布鲁线虫最具抗性。因此，控制对所有三种布鲁线虫易感性和抗性的基因可能与这些菌株中的突变位于同一条常染色体上。参考其他蚊子对不同寄生虫的黑化反应，讨论了丝虫幼虫细胞内黑化的意义。
