Schofield L, Uadia P
Department of Medical and Molecular Parasitology, New York University School of Medicine, New York 10010.
J Immunol. 1990 Apr 1;144(7):2781-8.
The anamnestic antibody response to synthetic peptide antimalarial vaccines is under Ir gene control. It has therefore been inferred that the development of antibody responses to the native repetitive Ag of malaria parasites also requires linkage of T and B cell epitopes, presentation of Ag in the context of MHC class II components, and cognate T cell help for antibody production. In this study, we sought to test this assumption, by utilizing classical protocols to determine whether the antibody response to the repetitive surface Ag of malaria sporozoites, the circumsporozoite (CS) protein, is under Ir gene control. In contrast to vaccine constructs, such as recombinant proteins or synthetic peptides, secondary responses to the repetitive oligomeric domains of the native CS protein of intact malaria sporozoites do not require the presence of Ag-specific Th cells. Conferral of CS-specific Th cells does not appear to influence the magnitude of this thymus-independent response to sporozoites. In further contrast to synthetic CS analogs, exposure to the parasite appears to be associated with low levels of Ag-specific Th cell sensitization. These observations suggest a functional role in immune evasion for the immunodominant repetitive domains found within protein Ag of malaria and other parasites.
对合成肽抗疟疫苗的回忆性抗体反应受Ir基因控制。因此据推断，对疟原虫天然重复抗原产生抗体反应也需要T细胞和B细胞表位的连接、在MHC II类成分背景下呈递抗原以及产生抗体时相关T细胞的辅助。在本研究中，我们试图通过使用经典方案来检验这一假设，以确定对疟原虫子孢子的重复表面抗原即环子孢子（CS）蛋白的抗体反应是否受Ir基因控制。与疫苗构建体（如重组蛋白或合成肽）不同，对完整疟原虫子孢子天然CS蛋白的重复寡聚结构域的二次反应不需要存在抗原特异性Th细胞。赋予CS特异性Th细胞似乎不影响这种对子孢子的非胸腺依赖性反应的强度。与合成CS类似物进一步不同的是，接触寄生虫似乎与低水平的抗原特异性Th细胞致敏有关。这些观察结果表明，疟疾和其他寄生虫蛋白质抗原中发现的免疫显性重复结构域在免疫逃避中具有功能性作用。
