Darrieux M, Miyaji E N, Ferreira D M, Lopes L M, Lopes A P Y, Ren B, Briles D E, Hollingshead S K, Leite L C C
Centro de Biotecnologia, Instituto Butantan, Av. Vital Brasil 1500, 05509-900 São Paulo, SP, Brazil.
Infect Immun. 2007 Dec;75(12):5930-8. doi: 10.1128/IAI.00940-07. Epub 2007 Oct 8.
PspA is an important pneumococcal vaccine candidate that is capable of inducing protection in different animal models. Because of its structural diversity, a PspA-based vaccine should contain at least one fragment from each of the two major families (1 and 2) in order to elicit broader protection. In the present work, we have tested the potential of PspA hybrids containing fused portions of family 1 and 2 (PspA1ABC-4B and PspA1ABC-3AB) PspA fragments to induce protection against pneumococci bearing distinct PspA fragments. Sera from mice immunized with these hybrid PspA fragments were able to increase C3 deposition on pneumococci bearing PspA fragments from both families, in contrast with sera made against the PspA family 1 (PspA1ABC) and PspA family 2 (PspA3ABC) fragments, which were effective only within the same family. Although PspA hybrids were able to extend protection against pneumococcal infection with strains bearing diverse PspA fragments, the immunity elicited by family 2 was clade dependent, suggesting that PspA fragments from family 2 clades 3 and 4 should both be included in a comprehensive PspA vaccine. These results indicate that PspA fusion proteins constitute an efficient immunization strategy for future PspA-based antipneumococcal vaccines since they are able to extend protection provided by a protein derived from a single transcript.
肺炎球菌表面蛋白A(PspA)是一种重要的肺炎球菌疫苗候选物,能够在不同动物模型中诱导产生保护作用。由于其结构多样性,基于PspA的疫苗应包含来自两个主要家族(1和2)中每个家族的至少一个片段,以便引发更广泛的保护。在本研究中,我们测试了含有家族1和2融合部分(PspA1ABC - 4B和PspA1ABC - 3AB)的PspA杂交片段诱导针对携带不同PspA片段的肺炎球菌产生保护的潜力。用这些杂交PspA片段免疫的小鼠血清能够增加C3在携带来自两个家族PspA片段的肺炎球菌上的沉积,这与针对PspA家族1(PspA1ABC)和PspA家族2(PspA3ABC)片段产生的血清形成对比,后者仅在同一家族内有效。尽管PspA杂交片段能够扩展针对携带不同PspA片段菌株的肺炎球菌感染的保护作用,但家族2引发的免疫是进化枝依赖性的,这表明来自家族2进化枝3和4的PspA片段都应包含在全面的PspA疫苗中。这些结果表明,PspA融合蛋白构成了一种有效的免疫策略,可用于未来基于PspA的抗肺炎球菌疫苗,因为它们能够扩展由单个转录本衍生的蛋白质所提供的保护。