Immune Dampening the OMPs of non-typeable H. influenzae

描述(由申请人提供)：针对病毒、细菌和寄生虫的新疫苗开发的最具挑战性的方面之一是克服抗原变异的问题。针对引起中耳炎的病原体的疫苗的开发正被许多团体积极追求，但由于其抗原的多样性，疫苗的开发在很大程度上是复杂的。我们对三种主要细菌(非分型流感嗜血杆菌(NTHI)、肺炎链球菌和卡他莫拉菌)各自的致病机制及其病毒共病原体(流感、鼻病毒、腺病毒等)的不完全了解，以及对OM时儿科免疫反应的不充分理解，带来了多重独特的挑战。NTHI是儿童中耳炎(OM)的主要致病菌，在不同菌株之间表现出相当大的变异。主要外膜蛋白(OMP)是血清抗体的主要靶点，也是疫苗研制的重要靶点。免疫学研究一致表明，抗体针对OMP表面环结构中的免疫优势线性表位，这些表位依赖于菌株，经历抗原变异，使儿童无法抵御其他循环中的NTHI逃逸变体和菌株。对其中两个OMP，P2和P5蛋白的详细研究表明，这些OMP的某些区域显示出较少的序列变异。因此，使用从该结果中选择的多肽，在免疫后产生更广泛的杀菌抗体。检测表面概率、亲水性、灵活性和抗原性的免疫学和生物物理研究强烈表明，在自然条件下免疫原性较差的蛋白质额外的、更高度保守的区域可以成为免疫原性。 通过选择性遗传不稳定性促进的抗原变异显然是许多微生物病原体采用的一种成功的免疫学策略。将其与蛋白质结构上选择性和集中的免疫优势相结合，有助于防止免疫系统识别分子上的其他抗原结构。这些OMPS结构的“诱骗”表位导致了分离株、株系或血清型的特异性抗体反应。宿主免疫系统似乎专注于这些更明显的诱骗表位，代价是完全识别表面蛋白结构内和表面蛋白结构之间的其他保守和保护性表位。这项建议的目的是进一步测试免疫抑制技术，作为一种策略，将免疫反应的重点从P2和P5中的免疫优势、非保护性或血清型限制表位，转向更广泛的保护性表位，这些表位(在自然条件下)抗原性相对较低。免疫受抑和重新聚焦的P2和P5将单独和联合检测它们诱导跨株保护性抗体的能力。免疫抑制技术提供了一种绕过抗原变异问题的新方法，并可能有助于创造更广泛的保护性疫苗，以对抗人和动物的各种细菌、病毒和寄生虫病。

DESCRIPTION (provided by applicant): One of the most challenging aspects of new vaccine development for viruses, bacteria and parasites is overcoming problems of antigenic variation. The development of vaccines against pathogens, which cause otitis media are being vigorously pursued by many groups, but is complicated in a significant way due to their antigenic diversity. Our incomplete understanding of the pathogenic mechanisms used by each of the three major bacterial species (nontypeable Haemophlius influenzae (NTHI), Streptococcus pneumoniae and Moraxella catarrhalis), their viral co-pathogens (Influenza, Rhinovirus, Adenovirus etc) and our inadequate understanding of the pediatric immune response during OM has presented multiple unique challenges. NTHI, a major bacterial pathogen of Otitis Media (OM) in children exhibits considerable strain-to-strain variation. The major outer membrane proteins (OMP) appear to be the major target of serum antibody and important targets of vaccine development. Immunological studies consistently show the antibody is directed to immunodominant, linear epitopes in surface loop structures of the OMPs which are strain dependent, undergo antigenic variation and leave the child unprotected against other circulating NTHI escape variants and strains. Detailed studies of two of these OMPs, the P2 and P5 proteins suggest that some regions of these OMPs exhibit less sequence variation. Thus using selected peptides from this result in the production of more broadly bactericidal antibody following immunization. Immunological and biophysical studies examining surface probability, hydrophilicity, flexibility, and antigenicity plots, strongly suggest that additional, more highly conserved regions of the protein, which are poorly immunogenic under natural conditions, could become immunogenic. Antigenic variation promoted through selective genetic instability is obviously a successful immunological strategy employed by many microbial pathogens. Coupling this to selective and focused immunodominance on the protein structure serves to prevent the immune system from recognizing other antigenic structures on the molecule. These "decoying" epitopes of the OMPs structure results in isolate-, strain- or serotype-specific antibody responses. The host immune system appears fixated on these more visible decoying epitopes at the cost of fully recognizing other conserved and protective epitopes within and between surface protein structures. The objective of this proposal is to further test the technology of immune dampening as a strategy to refocus the immune responses away from immunodominant, non-protective or serotype-restricted epitopes in P2 and P5, towards more broadly protective epitopes which (under natural conditions) are relatively less antigenic. The immune dampened and refocused P2 and P5 will be tested singly and in combination for their ability to induce cross strain protective antibody. Immune dampening technology provides for a new approach to circumventing the issues of antigenic variation and could help into the creation of more broadly protective vaccines against a variety of bacterial, viral and parasitic diseases of man and animals.