Immune Response to P. vivax in Duffy (-) Humans

描述(申请人提供)：每年3-5亿疟疾病例中，至少有20%是由间日疟原虫感染引起的。虽然间日疟很少致死，但在许多疟疾流行国家，它造成了巨大的人类痛苦，并抑制了经济发展。与最致命的人类疟疾寄生虫恶性疟原虫相比，对间日疟原虫的研究相对较少，主要是因为它不能在体外培养。因此，与恶性疟原虫相比，间日疟原虫疫苗的研发进展要少得多。间日疟原虫裂殖子对网织红细胞的侵袭依赖于网织红细胞表面达菲抗原/趋化因子受体(DARC)的表达。缺乏DARC[F(y-)J]的个体对间日疟原虫血液期感染完全抵抗，但应易受由子孢子入侵引起的肝期感染。此外，肝期寄生虫应该在FY(-)个体中正常发育，但从肝脏释放的裂殖子不会引发血期感染。因此，居住在间日疟原虫流行区的FY(-)个体暴露于受感染的蚊子后，应主要对肝期抗原产生免疫反应，而FY(+)个体应对肝期和血期抗原均有反应，主要反应针对血期抗原。在这里提出的新的检测方法中，应该可以使用来自FY(-)个体的淋巴细胞来鉴定间日疟原虫红细胞前期抗原。 它们是细胞免疫反应的目标。淋巴细胞和血清将从居住在哥伦比亚间日疟原虫流行区的FY(+)和FY(-)个人身上收集。新的ELISPOT分析和IF AS将用于表征对从间日疟原虫基因组序列中鉴定的100种新蛋白的免疫反应。免疫原性研究将在小鼠身上进行，以证实通过体外筛选过程在人类免疫细胞中鉴定的抗原蛋白在体内具有免疫原性，并产生用于亚细胞定位的抗血清以确认新抗原的阶段特异性。

DESCRIPTION (provided by the applicant): At least 20% of the 300-500 million annual cases of malaria are caused by infection with Plasmodium vivax. Although P. vivax malaria is rarely lethal, it causes a great deal of human suffering and inhibits economic development in many malaria-endemic countries. P. vivax is relatively little studied compared to the most lethal human malaria parasite P. falciparum, primarily because it cannot be cultured in vitro. Consequently, far less progress has been achieved in P. vivax vaccine development compared to P. falciparum. Invasion of P. vivax merozoites into reticulocytes is dependent upon the expression of the Duffy antigen/receptor for chemokines (DARC) on the reticulocyte surface. Individuals lacking DARC [F(y-)J are completely resistant to infection by P. vivax blood stages, but should be susceptible to liver stage infections initiated by the invasion of sporozoites. Furthermore, liver stage parasites should develop normally in Fy(-) individuals, but the merozoites released from the liver would not be expected to initiate blood stage infections. Consequently, Fy(-) individuals residing in P. vivax endemic areas who are exposed to infected mosquitoes should exhibit immune responses primarily to liver stage antigens, whereas Fy(+) individuals should respond to both liver and blood stage antigens, with a predominant response directed to the blood stage antigens. It should be possible to use lymphocytes from Fy(-) individuals in novel assays proposed here to identify pre-erythrocytic stage P. vivax antigens that are targets of cellular immune responses. Lymphocytes and sera will be collected from Fy(+) and Fy(-) individuals living in P. vivax endemic areas in Columbia. Novel ELISPOT assays and IF As will be used to characterize the immune responses to 100 novel proteins identified from the P. vivax genome sequence. Immunogenicity studies will be conducted in mice to confirm that the antigenic proteins identified through the in vitro screening process in human immune cells are immunogenic in vivo, and to generate the antisera for subcellular localization to confirm the stage specificity of the novel antigens.