Role of Heat Shock Protein against Protozoan Infection

将细胞暴露在各种应激条件下，如高温、化学中毒或感染，会导致一系列基因的转录，随后合成一系列称为热休克蛋白(HSPs)的多肽。这些蛋白质在从原核生物到真核生物的整个进化过程中都保留了高度保守的氨基酸序列。由于热休克蛋白被认为是与无菌微生物感染有关的常见免疫原，这些蛋白正在被详细研究。然而，很难定义HSPs在感染和免疫中的作用，因为它们都是处于感染状态的宿主和微生物中的HSPs，而且它们具有高度的同源性。对于细胞内的寄生虫，热休克蛋白可能是这些生物适应宿主的严格环境以及将生物转化为传染性形式所必需的。寄生虫的热休克蛋白也是免疫优势肽，可被宿主体液和…识别。更多的细胞免疫系统。另一方面，在某些感染过程中对压力做出反应时合成的热休克蛋白实际上可能在宿主防御中发挥作用。因此，表达宿主或寄生虫的HSPs可能具有调节宿主-寄生虫关系的潜力。我们研究了65 kDa热休克蛋白(HSP65)在专性胞内原生动物弓形虫(T.Gondii)感染中的作用。在人类中，这种普遍存在的寄生虫很少会在免疫功能正常的人身上引起疾病，但它会在免疫功能低下的宿主(例如艾滋病患者)中产生严重的机会性感染症状。考虑到全世界艾滋病宿主的数量不断增加，了解这种原虫的生命周期以及保护性免疫是如何实现对这种寄生虫和其他寄生虫的保护是很重要的。我们在这里提出，HSP65在宿主巨噬细胞上/在宿主巨噬细胞中的表达是由Gammadelta T细胞诱导的，它在抵抗弓形虫感染方面发挥着重要作用。此外，我们发现HSP65可以有效地保护感染的巨噬细胞免受细胞凋亡的影响。对这些关系的分析将有助于宿主-寄生虫与弓形虫的相互作用，并将指导人们对热休克蛋白在感染除弓形虫以外的许多细胞内病原体中所扮演的角色的推测。较少

Exposing cells to a variety of stressful conditions such us elevated temperature, chemical intoxication or infection leads to the transcription of a set of genes and subsequently, to the synthesis of a family of polypeptides called heat shock proteins (HSPs). These proteins have retained highly conserved amino acid sequences throughout evolution from prokaryotes to eukaryotes. Since HSPs are proposed as common immunogens involved in infections with unmerous microorganisms, these proteins are being studied in detail. However, it is difficult to define the role of HSPs in infection and immunity, since these are HSPs in the both hosts and microorganisms in infection states, and since they are highly homologous. For intracellular parasites, HSPs may be essential for the adaptation of those organisms to the strict environment of hosts, and for transformation of organisms to infectious form. HSPs of parasites also function as immunodominant peptides that can be recognized by host humoral and … More cellulaar immune systems. On the other hand, HSPs synthesized as they respond to stress during certain infection may actually play a role in host defense. Thus, HSPs expressed either the hosts or parasites may have a potential to modulate the host-parasite relationship.We investigated the involvement of the 65 kDa heat shock protein (HSP65) in infection with an obligate intracellular protozoan Toxoplasma gondii (T.gondii). In humans, this ubiquitous parasite rarely causes diseases in individuals of normal immunocompetence, but it produces severe symptoms as an opportunistic infection in immunocompromized hosts, for example patient with AIDS.Considering the increasing number of hosts with AIDS throughout the world, it is important to understand the life cycle of this protozoan and how the protective immunity achieves towards this and other parasites.We present here that HSP65 expression on/in host macrophages is induced by gammadelta T cells and that it plays an important role in resistance against infection with T.gondii. Further , we found that HSP65 can be effective in protecting infected macrophages from apoptotic cell death. Analysis of these relationships should contribute to host-parasite interactions with T.gondii and should guide speculation on role playd by HSPs in infection with numerous intracellular pathogens other than T.gondii such as Leishmania major, Trypanosoma cruzi and malaria protozoa. Less