Chougnet C, Troye-Blomberg M, Deloron P, Kabilan L, Lepers J P, Savel J, Perlmann P
INSERM U13/Institut de Médecine et d'Epidémiologie Africaine, Hôpital Claude Bernard, Paris, France.
J Immunol. 1991 Oct 1;147(7):2295-301.
Autologous cell mixtures containing T cells, B cells, and adherent accessory cells from individuals primed to the malaria parasite Plasmodium falciparum by repeated natural infections were investigated for induction of Ig and antibody secretion in vitro. In vitro activation of cell cultures with two synthetic peptides corresponding to immunodominant T cell epitopes of the merozoite Ag ring-infected erythrocyte surface Ag (Mr 155,000) (Pf155/RESA), one from its carboxyl-terminal repeat and one from its nonrepeated amino-terminal region, gave rise to significant IgG secretion. Supernatants from lymphocyte cultures activated with either one of these peptides contained antibodies reacting with P. falciparum Ag in immunofluorescence assays and with Pf155/RESA peptides in a slot blot assay. No anti-P. falciparum antibodies were induced in the medium controls by lymphocyte stimulation with either tetanus toxoid or PWM. Induction in vitro of anti-Pf155/RESA antibodies was correlated with the presence of such antibodies in the sera of the lymphocyte donors, suggesting that the induction of antibody secretion reflected a secondary response in vitro of in vivo primed cells. Inspection of antibody profiles in individual donors revealed that the peptide corresponding to a sequence in the 3' repeat region induced anti-Pf155/RESA peptide antibodies reacting with identical or related and cross-reacting sequences in the 3' or 5' repeat region of the molecule. In contrast, the peptide corresponding to a nonrepeated T cell epitope in the amino terminus of the molecule only induced antibodies to an immunodominant amino-terminal B cell epitope partly overlapping with the T cell reactive sequence. Similar findings were made in the lymphocyte donors' plasma, frequently displaying significant correlations between antibody reactivities to the repeat peptides but not between these reactivities and those to the amino-terminal peptide. The marked specificity of this antibody formation in vitro suggests an underlying process of cognate recognition involving Ag-specific T and B cells reacting with different segments of the inducer peptide. The present experimental system should be well suited for identification of Th epitopes capable of inducing the production of antibodies of defined specificity in the human system.
对来自因反复自然感染而对疟原虫恶性疟原虫致敏的个体的含有T细胞、B细胞和黏附辅助细胞的自体细胞混合物进行了体外诱导Ig和抗体分泌的研究。用两种合成肽激活细胞培养物，这两种合成肽对应于裂殖子抗原环感染红细胞表面抗原（分子量155,000）（Pf155/RESA）的免疫显性T细胞表位，一种来自其羧基末端重复序列，另一种来自其非重复氨基末端区域，可引起显著的IgG分泌。用这些肽中的任何一种激活的淋巴细胞培养物的上清液在免疫荧光试验中含有与恶性疟原虫抗原反应的抗体，在狭缝印迹试验中含有与Pf155/RESA肽反应的抗体。用破伤风类毒素或PWM刺激淋巴细胞，在培养基对照中未诱导出抗恶性疟原虫抗体。体外诱导抗Pf155/RESA抗体与淋巴细胞供体血清中此类抗体的存在相关，这表明抗体分泌的诱导反映了体内致敏细胞在体外的二次反应。对个体供体抗体谱的检查发现，对应于3'重复区域序列的肽诱导的抗Pf155/RESA肽抗体与该分子3'或5'重复区域中相同或相关且交叉反应的序列反应。相反，对应于分子氨基末端非重复T细胞表位的肽仅诱导针对与T细胞反应序列部分重叠的免疫显性氨基末端B细胞表位的抗体。在淋巴细胞供体的血浆中也有类似的发现，抗体对重复肽的反应性之间经常显示出显著的相关性，但这些反应性与对氨基末端肽的反应性之间没有相关性。这种体外抗体形成的显著特异性表明存在一种同源识别的潜在过程，涉及与诱导肽不同片段反应的抗原特异性T细胞和B细胞。本实验系统应非常适合于鉴定能够在人体系统中诱导产生具有特定特异性抗体的Th表位。
