H. INFLUENZAE HMW ADHESION PROTEINS IN HOST IMMUNITY

非分型流感嗜血杆菌(NTHI)引起的中耳炎和其他疾病仍然是我国和世界其他地方儿童的重大健康问题。该项目的长期目标是确定在保护性宿主免疫反应中重要的NTHI表面暴露的细菌抗原，并最终解决由这些抗原组成的疫苗在预防疾病方面是否有效的问题。在以前的工作中，我们发现HMW1/HMW2家族蛋白是自然感染和定居后人类血清抗体反应的主要靶点。此外，我们还证明了这些蛋白在NTHI与真核细胞的黏附中起着关键作用。关于这些蛋白作为候选疫苗的潜力，我们证明了用HMW1/HMW2混合物免疫栗鼠可以预防由同源菌株引起的实验性NTHI中耳炎。最后，在我们的初步研究中，我们证明了针对HMW1/HMW2家族蛋白的成人血清抗体介导了针对同源和异源菌株的吞噬细胞活性。我们建议在这些早期研究的基础上，以下列具体目标为基础。我们将表征针对HMW1/HMW2样蛋白产生的抗体对急性NTHI中耳炎儿童恢复期血清中产生的吞噬细胞活性的贡献。我们将定位HMW1/HMW2样蛋白的那些区域，这些区域表达能够介导针对同源和异源菌株的吞噬细胞活性的抗体识别的表位。最后，我们将在实验性NTHI中耳炎的栗鼠模型中评估表达由抗体识别的表位的重组蛋白对同源和异种菌株的吞噬细胞活性提供疾病保护的能力。从这些研究中获得的知识将为针对HMW1/HMW2蛋白的抗体在宿主免疫中的作用提供更清晰的图景，并可能使我们更接近开发疫苗以预防幼儿非分型流感嗜血杆菌中耳炎和其他疾病的目标。

Otitis media and other illnesses caused by nontypable Haemophilus influenzae (NTHI) remain significant health problems for children in this country and elsewhere in the world. The long-term objectives of this project are to identify those surface-exposed bacterial antigens of NTHI that are important in a protective host immune response and ultimately to address the question of whether or not a vaccine composed of such antigens would be effective in the prevention of disease. In previous work, we identified the HMW1/HMW2 family of proteins as major targets of the human serum antibody response following natural infection and colonization. Furthermore, we demonstrated a critical role for these proteins in adhesion of NTHI to eukaryotic cells. With respect to the potential of these proteins as vaccine candidates, we demonstrated that immunization of chinchillas with an HMW1/HMW2 mixture provided protection against experimental NTHI otitis media caused by the homologous strain. Finally, in our preliminary studies, we demonstrated that adult human serum antibodies specific for the HMW1/HMW2 family of proteins mediate opsonophagocytic activity against both homologous and heterologous strains. We propose to build on these earlier studies with the following specific aims. We will characterize the contribution of antibodies produced against the HMW1/HMW2- like proteins to the opsonophagocytic activity that develops in convalescent sera of children with acute NTHI otitis media. We will map those regions of the HMW1/HMW2-like proteins that express epitopes recognized by antibody capable of mediating opsonophagocytic activity against both homologous and heterologous strains. Finally, we will assess the ability of recombinant proteins that express epitopes recognized by antibodies mediating opsonophagocytic activity against homologous and heterologous strains to provide protection against disease in the chinchilla model of experimental NTHI otitis media. The knowledge gained from these studies will provide a clearer picture of the role of antibody to the HMW1/HMW2 proteins in host immunity and may move us closer to the goal of developing vaccines for prevention of nontypable Haemophilus influenzae otitis media and other diseases in young children.