Department of Medical Entomology and Vector Control, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
PLoS One. 2013 Sep 23;8(9):e75413. doi: 10.1371/journal.pone.0075413. eCollection 2013.
There are varying degrees of compatibility between malaria parasite-mosquito species, and understanding this compatibility may be crucial for developing effective transmission-blocking vaccines. This study investigates the compatibility of different biological forms of a malaria vector, Anopheles stephensi, to Plasmodium berghei ANKA strain.
Several biologically different and allopatric forms of A. stephensi were studied. Three forms were isolated from different regions of southern Iran: the variety mysorensis, the intermediate form and the native type form, and an additional type form originated from India (Beech strain).The mosquitoes were experimentally infected with P. berghei to compare their susceptibility to parasitism. Anti-mosquito midgut antiserum was then raised in BALB/cs mice immunized against gut antigens from the most susceptible form of A. stephensi (Beech strain), and the efficacy of the antiserum was assessed in transmission-blocking assays conducted on the least susceptible mosquito biological form.
The susceptibility of different biological forms of A. stephensi mosquito to P. berghei was specifically inter-type varied. The Beech strain and the intermediate form were both highly susceptible to infection, with higher oocyst and sporozoite infection rates than intermediate and mysorensis forms. The oocyst infection, and particularly sporozite infection, was lowest in the mysorensis strain. Antiserum raised against midgut proteins of the Indian Beech type form blocked infection in this mosquito population, but it was ineffective at blocking both oocyst and sporozoite development in the permissive but geographically distant intermediate form mosquitoes. This suggests that a strong degree of incompatibility exists between the mosquito strains in terms of midgut protein(s) acting as putative ookinete receptors.
The incompatibility in the midgut protein profiles between two biological forms of A. stephensi demonstrates a well-differentiated population structure according to geographical origin. Therefore, the design of potential transmission-blocking strategies should incorporate a more thorough understanding of intra-species variations in host-parasite interactions.
疟原虫-蚊子种间存在不同程度的兼容性，了解这种兼容性对于开发有效的传播阻断疫苗可能至关重要。本研究调查了不同生物型的疟疾媒介按蚊，即 A. stephensi，与 P. berghei ANKA 株的兼容性。
研究了几种不同的、地理上不同的 A. stephensi 生物型。三种形式分别从伊朗南部的不同地区分离出来：变种 mysorensis、中间形式和本地类型形式，以及一种来自印度的额外类型形式（Beech 株）。用 P. berghei 实验感染蚊子，以比较它们对寄生的敏感性。然后，用 BALB/cs 小鼠免疫来自最易感 A. stephensi 形式（Beech 株）的肠道抗原产生抗蚊中肠抗血清，并在最不敏感的蚊子生物型上进行传播阻断试验评估抗血清的功效。
不同生物型 A. stephensi 蚊子对 P. berghei 的敏感性具体为种间变化。Beech 株和中间型都高度易感感染，其卵囊和孢子感染率高于中间型和 mysorensis 型。在 mysorensis 株中，卵囊感染率，特别是孢子感染率最低。针对印度 Beech 型中肠蛋白产生的抗血清阻断了该蚊群的感染，但在允许但地理上遥远的中间型蚊子中，它对卵囊和孢子的发育都没有作用。这表明在作为假定的动合子受体的中肠蛋白方面，蚊子种群之间存在很强的不兼容性。
两种 A. stephensi 生物型的中肠蛋白不兼容性表明，根据地理起源，存在分化良好的种群结构。因此，潜在的传播阻断策略的设计应纳入对宿主-寄生虫相互作用种内变异的更深入了解。
