Studies on gene analysis and immunological function of 47KD polypeptide of Plasmodium falciparum.

通过对流行区人群免疫状况的比较研究，将有助于阐明与保护性免疫相关的抗原表位。目前的研究是通过使用抗恶性疟原虫多克隆抗体从流行的热带地区的个人，也从病人谁开发的恶性疟原虫疟疾在日本。经免疫印迹分析，急性期血清中出现了一个特异性的47 kD分子（pf 47 kD），推测pf 47 kD是疟原虫感染早期诱导免疫反应的抗原表位。为研究pf 47 kD在寄生虫体内的定位，研制了一株单克隆抗体。激光扫描荧光显微镜观察显示pf 47 kD位于发育中的鞭毛体表面。对编码pf 47 kD序列的寄生虫基因进行了研究。从培养的恶性疟原虫制备cDNA文库，并连接到载体并导入宿主细胞。通过使用高滴度的多克隆抗体和单克隆抗体进行筛选。pf 47 kD序列与人pf 47 kD基因序列一致。原因还在研究中。同时，采用高效液相色谱法对抗原进行了纯化，并进行了序列分析，将结果与上述结果进行了比较研究。在田间研究中，通过使用慢性型恶性疟原虫感染的血清，突出了23 kD的寄生虫分子。这种分子似乎诱导了另一种类型的保护性免疫反应。此外，利用近交系小鼠和猴动物模型研究了细胞因子在保护性免疫中的作用。INF-γ和TNF-α在疟疾感染中起保护作用，并可能在有害反应中起作用。

Comparative studies on immunue status of individuals living in the endemic areas will elucidate the antigen epitopes related to protective immunity. Present study was performed by using anti-P.falicparum polyclonal antibodies taken from individuals in the endemic tropical areas and also from patients who developed falciparum malaria in Japan. By an immunoblotting, electrophoresed 47kD molecule (pf47kD) was presented by the sera taken from the acute phase of the infection, thus it was presumed that pf47kD was a parasite epitope inducing immune reactions at an early stage of malaria infection. One monoclonal antibody was developed to study localization of pf47kD in the parasite. A lazer-scanning fluorescent microscopy rvealed that pf47kD was on the surface of developing schizont. Studies on parasite gene which encodes the pf47kD sequence was attempted. cDNA library from the clutured falciparum parasite was prepared and were ligated to vectors and were introduced into host cells. Screening was processed by using high titered polyclonal antibodies and the monoclonal antibody. the resulted pf47kD sequence was coincidental with an sequence of human gene. The reason is still on the study. Simultaneously, the parasite antigen was purified by using HPLC to analyze the sequence and results will be comparatively studied with the results shown above. In the field studies, a 23kD parasite moleculte was highlighted by the use of the sera from chronic type of P.falciparum infection. The molecule seemed to induce another type of protective immune reaction. In addition, roles of cytokines in the protective immunity was studied using animal models of inbred mice and monkeys. INF-gamma and TNF-alpha worked in the protection and probably in the detrimental reaction in malaria infection.