Zhang Ping, Jespersgaard Christina, Lamberty-Mallory Leticia, Katz Jannet, Huang Yan, Hajishengallis George, Michalek Suzanne M
Departments of Microbiology. Oral Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294.
Infect Immun. 2002 Dec;70(12):6779-87. doi: 10.1128/IAI.70.12.6779-6787.2002.
The saliva-binding region (SBR) of the cell surface antigen I/II (AgI/II) and the glucan-binding region (GLU) of the glucosyltransferase enzyme of Streptococcus mutans have been implicated in the initial adherence of S. mutans to saliva-coated tooth surfaces and the subsequent sucrose-dependent accumulation of S. mutans, respectively. Here, we describe the construction and characterization of a genetic chimeric protein consisting of the two virulence determinants SBR and GLU (SBR-GLU). The effectiveness of this construct in inducing mucosal and systemic immune responses to each virulence determinant following intranasal immunization was compared to that of each antigen alone or an equal mixture of SBR and GLU (SBR+GLU) in a mouse model. Furthermore, the ability of antibodies induced to SBR-GLU to protect against S. mutans infection was also investigated. Immunization of mice with the chimeric protein SBR-GLU resulted in significantly enhanced (P < 0.001) levels of serum immunoglobulin G (IgG) anti-SBR antibody activity compared to those in the SBR and SBR+GLU groups. The SBR-GLU-immunized mice also demonstrated a significant (P < 0.05) increase in salivary and vaginal IgA antibody responses to SBR and GLU. Analysis of the serum IgG subclass responses to SBR in mice immunized with SBR alone indicated a mixed IgG1 and IgG2a response. A preferential IgG1 response compared to an IgG2a anti-GLU response was induced in mice immunized with GLU alone. Similarly, a preferential IgG1 response was also induced to SBR when GLU was present in either a mixed or conjugated form. Finally, a significant reduction (P < 0.05) in S. mutans colonization was observed only in mice immunized with the SBR-GLU chimeric protein. Taken together, our results indicate that the chimeric protein SBR-GLU significantly enhanced mucosal immune responses to SBR and GLU and systemic immune responses to SBR. The ability of SBR-GLU to induce responses effective in protection against colonization of S. mutans suggests its potential as a vaccine antigen for dental caries.
变形链球菌细胞表面抗原I/II（AgI/II）的唾液结合区域（SBR）和葡糖基转移酶的葡聚糖结合区域（GLU）分别与变形链球菌在唾液包被的牙齿表面的初始黏附以及随后的变形链球菌蔗糖依赖性聚集有关。在此，我们描述了一种由两个毒力决定因素SBR和GLU组成的基因嵌合蛋白（SBR-GLU）的构建和表征。在小鼠模型中，将该构建体在鼻内免疫后诱导对每个毒力决定因素的黏膜和全身免疫反应的有效性与单独的每种抗原或SBR和GLU的等量混合物（SBR+GLU）进行了比较。此外，还研究了诱导产生的针对SBR-GLU的抗体预防变形链球菌感染的能力。与SBR组和SBR+GLU组相比，用嵌合蛋白SBR-GLU免疫小鼠导致血清免疫球蛋白G（IgG）抗SBR抗体活性水平显著提高（P<0.001）。用SBR-GLU免疫的小鼠在唾液和阴道中对SBR和GLU的IgA抗体反应也显著增加（P<0.05）。对单独用SBR免疫的小鼠血清IgG亚类对SBR的反应分析表明是IgG1和IgG2a的混合反应。单独用GLU免疫的小鼠诱导出与抗GLU的IgG相比更偏向IgG1的反应。同样，当GLU以混合或结合形式存在时，对SBR也诱导出更偏向IgG1的反应。最后，仅在用SBR-GLU嵌合蛋白免疫的小鼠中观察到变形链球菌定植显著减少（P<0.05）。综上所述，我们的结果表明嵌合蛋白SBR-GLU显著增强了对SBR和GLU的黏膜免疫反应以及对SBR的全身免疫反应。SBR-GLU诱导有效预防变形链球菌定植的反应的能力表明其作为龋齿疫苗抗原的潜力。
