Zhao Xin, Alves e Silva Thiago Luiz, Cronin Laura, Savage Amy F, O'Neill Michelle, Nerima Barbara, Okedi Loyce M, Aksoy Serap
Yale School of Public Health, Department of Epidemiology of Microbial Diseases, New Haven, Connecticut, United States of America.
National Livestock Resources Institute, Tororo, Uganda.
PLoS Negl Trop Dis. 2015 Aug 27;9(8):e0004038. doi: 10.1371/journal.pntd.0004038. eCollection 2015.
Tsetse are vectors of pathogenic trypanosomes, agents of human and animal trypanosomiasis in Africa. Components of tsetse saliva (sialome) are introduced into the mammalian host bite site during the blood feeding process and are important for tsetse's ability to feed efficiently, but can also influence disease transmission and serve as biomarkers for host exposure. We compared the sialome components from four tsetse species in two subgenera: subgenus Morsitans: Glossina morsitans morsitans (Gmm) and Glossina pallidipes (Gpd), and subgenus Palpalis: Glossina palpalis gambiensis (Gpg) and Glossina fuscipes fuscipes (Gff), and evaluated their immunogenicity and serological cross reactivity by an immunoblot approach utilizing antibodies from experimental mice challenged with uninfected flies. The protein and immune profiles of sialome components varied with fly species in the same subgenus displaying greater similarity and cross reactivity. Sera obtained from cattle from disease endemic areas of Africa displayed an immunogenicity profile reflective of tsetse species distribution. We analyzed the sialome fractions of Gmm by LC-MS/MS, and identified TAg5, Tsal1/Tsal2, and Sgp3 as major immunogenic proteins, and the 5'-nucleotidase family as well as four members of the Adenosine Deaminase Growth Factor (ADGF) family as the major non-immunogenic proteins. Within the ADGF family, we identified four closely related proteins (TSGF-1, TSGF-2, ADGF-3 and ADGF-4), all of which are expressed in tsetse salivary glands. We describe the tsetse species-specific expression profiles and genomic localization of these proteins. Using a passive-immunity approach, we evaluated the effects of rec-TSGF (TSGF-1 and TSGF-2) polyclonal antibodies on tsetse fitness parameters. Limited exposure of tsetse to mice with circulating anti-TSGF antibodies resulted in a slight detriment to their blood feeding ability as reflected by compromised digestion, lower weight gain and less total lipid reserves although these results were not statistically significant. Long-term exposure studies of tsetse flies to antibodies corresponding to the ADGF family of proteins are warranted to evaluate the role of this conserved family in fly biology.
采采蝇是致病性锥虫的传播媒介，锥虫是非洲人类和动物锥虫病的病原体。采采蝇唾液（唾液组）的成分在吸血过程中被引入哺乳动物宿主的叮咬部位，对采采蝇高效进食的能力很重要，但也会影响疾病传播，并可作为宿主接触的生物标志物。我们比较了两个亚属中四种采采蝇的唾液组成分： morsitans亚属的 morsitans采采蝇（Gmm）和淡足采采蝇（Gpd），以及 palpalis亚属的冈比亚采采蝇（Gpg）和fuscipes采采蝇（Gff），并通过免疫印迹法利用来自用未感染的采采蝇攻击的实验小鼠的抗体评估了它们的免疫原性和血清学交叉反应性。唾液组成分的蛋白质和免疫图谱因同一亚属中的采采蝇种类而异，显示出更大的相似性和交叉反应性。从非洲疾病流行地区的牛获得的血清显示出反映采采蝇种类分布的免疫原性图谱。我们通过液相色谱-串联质谱法（LC-MS/MS）分析了Gmm的唾液组组分，鉴定出TAg5、Tsal1/Tsal2和Sgp3为主要免疫原性蛋白，5'-核苷酸酶家族以及腺苷脱氨酶生长因子（ADGF）家族的四个成员为主要非免疫原性蛋白。在ADGF家族中，我们鉴定出四种密切相关的蛋白（TSGF-1、TSGF-2、ADGF-3和ADGF-4），它们均在采采蝇唾液腺中表达。我们描述了这些蛋白的采采蝇种类特异性表达谱和基因组定位。使用被动免疫方法，我们评估了重组TSGF（TSGF-1和TSGF-2）多克隆抗体对采采蝇适合度参数的影响。采采蝇有限地接触具有循环抗TSGF抗体的小鼠后，其吸血能力略有受损，表现为消化功能受损、体重增加减少和总脂质储备减少，尽管这些结果没有统计学意义。有必要对采采蝇进行长期暴露于与ADGF蛋白家族相对应的抗体的研究，以评估这个保守家族在采采蝇生物学中的作用。
