Parasite and Vector Biology Research Unit, Department of Microbiology and Parasitology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.
Research Foundation in Tropical Diseases and the Environment, P.O. Box 474, Buea, Cameroon.
Parasit Vectors. 2020 Feb 7;13(1):51. doi: 10.1186/s13071-020-3921-x.
Different immune mechanisms are capable of killing developmental stages of filarial nematodes and these mechanisms are also likely to vary between the primary and a challenge infection. However, the lack of a detailed analysis of cytokine, chemokine and immunoglobulin levels in human loiasis is still evident. Therefore, detailed analysis of immune responses induced by the different developmental stages of Loa loa in immune-competent BALB/c mice will aid in the characterization of distinct immune responses that are important for the immunity against loiasis.
Different developmental stages of L. loa were obtained from human peripheral blood (microfilariae, MF), the transmitting vector, Chrysops (larval stage 3, L3) and infected immune-deficient BALB/cRAG2γc mice (L4, L5, adult worms). Groups of wildtype BALB/c mice were then injected with the isolated stages and after 42 days post-infection (pi), systemic cytokine, chemokine and immunoglobulin levels were determined. These were then compared to L. loa-specific responses from in vitro re-stimulated splenocytes from individual mice. All parameters were determined using Luminex technology.
In a pilot study, BALB/c mice cleared the different life stages of L. loa within 42 days pi and systemic cytokine, chemokine and immunoglobulin levels were equal between infected and naive mice. Nevertheless, L. loa-specific re-stimulation of splenocytes from mice infected with L5, MF or adult worms led to induction of Th2, Th17 and chemokine secretion patterns.
This study shows that although host immunity remains comparable to naive mice, clearance of L. loa life-cycle development stages can induce immune cell memory leading to cytokine, chemokine and immunoglobulins secretion patterns which might contribute to immunity and protection against reinfection.
不同的免疫机制能够杀死丝虫的发育阶段，这些机制在初次感染和挑战感染之间也可能有所不同。然而，人体罗阿丝虫病细胞因子、趋化因子和免疫球蛋白水平的详细分析仍然明显缺乏。因此，详细分析罗阿丝虫的不同发育阶段在免疫功能正常的 BALB/c 小鼠中诱导的免疫反应将有助于描述对罗阿丝虫病免疫力至关重要的独特免疫反应。
从人外周血（微丝蚴，MF）、传播媒介 Chrysops（幼虫第 3 期，L3）和感染免疫缺陷 BALB/cRAG2γc 小鼠（L4、L5、成虫）中获得不同的发育阶段的 L. loa。然后，将野生型 BALB/c 小鼠分组注射分离的阶段，在感染后 42 天（pi），测定系统细胞因子、趋化因子和免疫球蛋白水平。然后将其与来自个体小鼠体外再刺激脾细胞的 L. loa 特异性反应进行比较。所有参数均使用 Luminex 技术确定。
在一项初步研究中，BALB/c 小鼠在 42 天 pi 内清除了 L. loa 的不同生活阶段，感染和未感染小鼠的系统细胞因子、趋化因子和免疫球蛋白水平相等。尽管如此，L5、MF 或成虫感染的小鼠脾细胞的 L. loa 特异性再刺激导致 Th2、Th17 和趋化因子分泌模式的诱导。
本研究表明，尽管宿主免疫仍然与未感染的小鼠相当，但 L. loa 生活史发育阶段的清除可以诱导免疫细胞记忆，导致细胞因子、趋化因子和免疫球蛋白分泌模式的产生，这可能有助于对再感染的免疫和保护。
