Kulane A, Siddique A B, Perlmann H, Ahlborg N, Roussilhon C, Tall A, Dieye A, Perlmann P, Troye-Blomberg M
Department of Immunology, Stockholm University, Sweden.
Acta Trop. 1997 Oct 14;68(1):37-51. doi: 10.1016/s0001-706x(97)00070-3.
While the C-terminal repeat region of Pf155/RESA, a Plasmodium falciparum vaccine candidate has been extensively studied for B- and T-cell reactivities, little is so far known about the non-repeat region in this respect. The present study aimed at investigating the non-repeat sequence 171-227 of Pf155/RESA for T- and B-cell epitopes. Eight overlapping peptides were synthesised and assayed for their ability to stimulate peripheral blood mononuclear cells obtained from P. falciparum-immune donors to proliferate and to induce secretion of interferon-gamma (IFN-gamma) and/or interleukin 4 (IL-4) using the ELISPOT assay. The plasmas of the corresponding donors were tested for antibody reactivity with the same peptides in ELISA. The individual cellular responses to the different peptides varied and in general they were not correlated, emphasising the importance of including several parameters for T-cell activation. The most frequent T-cell responses (proliferation, IFN-gamma and/or IL-4) were seen with two partially overlapping peptides corresponding to the sequences 171-185 and 181-195 that induced responses in 71 and 62% of the donors, respectively. Although, the frequency of responders was high, the magnitude of the responses was generally low. Two overlapping peptides corresponding to the sequence 186-206 bound antibodies from a large number of plasma samples. IL-4 producing cells were frequently found in donors whose sera contained antibodies to the corresponding peptide. However, there was no absolute correlation and many donors having anti-peptide antibodies could also be induced to produce IFN-gamma. In conclusion, the non-repeat region of Pf155/RESA contains several epitopes inducing functionally distinct T-cell responses. The sequence 171-206 was found to contain both B- and T-cell epitopes recognised by almost all individuals naturally primed to malaria. Thus, this sequence should be a useful tool in future immuno-epidemiological studies and/or for inclusion into a subunit vaccine against the asexual blood stages of the P. falciparum parasite.
虽然恶性疟原虫疫苗候选物Pf155/RESA的C末端重复区域已针对B细胞和T细胞反应性进行了广泛研究，但迄今为止，关于该区域的非重复区域在这方面的了解甚少。本研究旨在调查Pf155/RESA的非重复序列171 - 227中的T细胞和B细胞表位。合成了八个重叠肽，并使用ELISPOT测定法检测它们刺激从恶性疟原虫免疫供体获得的外周血单核细胞增殖以及诱导干扰素-γ（IFN-γ）和/或白细胞介素4（IL-4）分泌的能力。在ELISA中检测相应供体的血浆与相同肽的抗体反应性。对不同肽的个体细胞反应各不相同，总体上它们不相关，这强调了纳入多个T细胞激活参数的重要性。最常见的T细胞反应（增殖、IFN-γ和/或IL-4）出现在与序列171 - 185和181 - 195对应的两个部分重叠肽中，分别在71%和62%的供体中诱导反应。虽然反应者的频率很高，但反应的强度通常较低。与序列186 - 206对应的两个重叠肽与大量血浆样本中的抗体结合。在血清中含有针对相应肽的抗体的供体中经常发现产生IL-4的细胞。然而，没有绝对的相关性，许多具有抗肽抗体的供体也可以被诱导产生IFN-γ。总之，Pf155/RESA的非重复区域包含几个诱导功能不同的T细胞反应的表位。发现序列171 - 206同时包含几乎所有自然感染疟疾个体识别的B细胞和T细胞表位。因此，该序列应成为未来免疫流行病学研究和/或纳入针对恶性疟原虫无性血液阶段的亚单位疫苗的有用工具。
