Manipulating immunodominance in influenza HA

每种流感血凝素（HA）都是保守的和毒株特异性表位的嵌合体，其中一些表位被中和抗体识别。优先激发识别保守表位的中和抗体的流感疫苗将比现在使用的那些疫苗具有更广泛的保护性。了解受试者的暴露史、流感疫苗抗原的差异以及佐剂的添加如何使免疫应答偏向不同的HA表位，将使我们能够设计最佳疫苗。将检验以下三个假设。(1]由非复制型流感疫苗和由感染引起的B细胞库在多克隆活化程度和中和宽度方面不同。所引出的剧目， 有佐剂的和无佐剂的疫苗不同，因为佐剂扩大了识别表位的范围。（二） 广泛反应性抗体，包括识别异亚型茎表位的抗体，在真正的初次免疫后比在二次流感免疫后更不常见，这是由于通过多次HA刺激扩大了应答。(3)针对所需表位的抗体的有效诱导需要：（a）有利的种系抗体的增殖和（B）达到所需最终特异性的亲和力成熟途径。有 优选的种系前体和靶向特定表位的抗体的成熟途径。 假设1和2将通过绘制具有不同流感感染暴露史和/或用含佐剂或无佐剂疫苗免疫的人类受试者的库识别的表位来检验。我们将寻求广泛中和抗体（我们想要引发的抗体），以了解它们的生殖系前体和成熟途径。我们还将绘制与HA结合的所有抗体的表位图，以确定体液免疫系统“看到了什么”。“从这种映射中获得的见解将用于合理设计上级HA免疫原，这些免疫原将通过抗原工程、小鼠免疫、库分析和抗原重新设计的迭代循环来优化。抗原设计技术将 包括选择性表位呈递、表位掩蔽和种系抗体靶向，随后是引导亲和力成熟。这项工作揭示的抗原设计的原则，可以适用于多种病原体的疫苗是必要的保护性决定因素。

Each influenza hemagglutinin (HA) is a mosaic of conserved and strain-specific epitopes, some of which are recognized by neutralizing antibodies. An influenza vaccine that preferentially elicits neutralizing antibodies that recognize conserved epitopes will be more broadly protective than those now in use. Understanding how the exposure history of subjects, differences in influenza vaccine antigens, and the addition of adjuvants bias the immune response towards different HA epitopes will enable us to design optimal vaccines. The following three hypotheses will be tested. (1] The B-cell repertoires elicited by non-replicating influenza vaccines and by infection differ in degree of polyclonal activation and breadth of neutralization. The repertoires elicited by adjuvanted and non-adjuvanted vaccines differ because adjuvant broadens the range of recognized epitopes. (2] Broadly reactive antibodies, including those recognizing the heterosubtypic stem epitope, are less frequent after true primary than after secondary influenza immunization due to broadening of the response by multiple HA stimulations. (3) Efficient induction of antibodies against a desired epitope requires: (a] proliferation of a favorable germline antibody and (b) an affinity maturation pathway to a desired final specificity. There are preferred germline precursors and maturation pathways for antibodies targeting particular epitopes. Hypotheses 1 and 2 will be tested by mapping the epitopes recognized by the repertoires of human subjects with different exposure histories to influenza infection and/or immunization with adjuvanted or un-adjuvanted vaccines. We will seek broadly neutralizing antibodies (those we want to elicit) to understand their germline precursors and maturation pathways. We will also map the epitopes of the full range of antibodies that bind HA to determine what the humoral immune system "sees." The insights obtained from this mapping will be used to rationally design superior HA immunogens that will be optimized through an iterative cycle of antigen engineering, mouse immunization, repertoire analysis, and antigen redesign. Antigen design techniques will include selective epitope presentation, epitope masking, and germ-line antibody targetting followed by guided affinity maturation. The principles of antigen design revealed by this work could be applied to protective determinants of multiple pathogens for which vaccines are needed.