IMMUNOLOGY OF BABESIOSIS

血液寄生虫病在世界上一半的家畜中流行 生产地区和是改善的最重要的障碍 发展中国家的肉类和牛奶生产。据估计，超过 仅巴贝斯虫病一项就有5亿头牛面临风险，尽管几十年来 研究表明，目前尚无有效、实用、安全的防治手段。 使牲畜对这种疾病免疫。牛巴贝斯虫的病理学 牛的感染与恶性疟原虫引起的感染非常相似 人类感染，以全身性循环为特征 毛细管内寄生红细胞的干扰和隔离 床，尤其是在大脑里。开发一种成功的 Babesial疫苗是基于从急性肺炎中恢复的观察 感染与保护性免疫的发展有关，而且 寄生虫粗提物免疫可产生部分保护作用 对抗随后的挑战。然而，人们对此知之甚少。 保护性抗原的性质或它们引起的免疫反应。因为 细胞介导的免疫效应机制在获得 针对其他原生动物感染的保护性免疫，我们建议研究 巴贝斯虫特异性T细胞与巴贝斯虫蛋白的相互作用 在细胞和分子水平使用牛T细胞克隆和 纯化抗原和重组抗原。T细胞产生细胞因子的研究 刺激后的细胞和巨噬细胞及其对寄生虫的影响 生存能力，也将被检验。这项建议的目的是 识别保护性巴贝斯虫抗原及其免疫效应机制 在负责控制巴贝斯虫病的牛身上。这样的信息是 有助于合理设计针对这种疾病的疫苗以及 其他疾病，如疟疾，是由血原虫寄生虫引起的。

Hemoparasitic diseases are endemic in half of the world's livestock production areas and are the most important obstacle to the improvement of meat and milk production in developing nations. It is estimated that over 500 million cattle are at risk for babesiosis alone, and despite decades of research, there is still no effective, practical and safe means of immunizing livestock against this disease. The pathology of Babesia bovis infection in cattle is very similar to that caused by Plasmodium falciparum infection in humans, and is characterized by a generalized circulatory disturbance and sequestration of parasitized erythrocytes in the capillary beds, especially in the brain. The feasibility of developing a successful babesial vaccine is based on observations that recovery from an acute infection is associated with development of protective immunity, and that immunization with crude parasite extracts can induce partial protection against subsequent challenge. However, very little is known about the nature of protective antigens or the immune responses they evoke. Because cell-mediated immune effector mechanisms are crucial in obtaining protective immunity against other protozoan infections, we propose to study the interactions of Babesia-specific T cells and defined babesial protein antigens at the cellular and molecular level using bovine T cell clones and purified as well as recombinant antigens. The production of cytokines by T cells and macrophages following stimulation, and their effect on parasite viability, will also be examined. The intent of this proposal is to identify protective babesial antigens and immunologic effector mechanisms in cattle responsible for controlling babesiosis. Such information is useful for the rational design of a vaccine against this disease as well as others, such as malaria, caused by hemoprotozoan parasites.