Function of NALT in nasal immunization to heterotypic strains of influenza

描述(申请人提供)：冷适应流感疫苗(CAV)是感染上呼吸道的减毒活病毒，包括鼻腔相关淋巴组织(NALT)。由于NALT是一种粘膜淋巴器官，它被推定为指导B和T细胞的发育，从而最有效地保护呼吸道。尽管CAV流感疫苗有潜在的好处，但由于担心当代流感病毒株与疫苗株之间的重组，使用这些疫苗来激发对人畜共患病病毒(如H5N1禽流感)的免疫力是有限的。此外，CAV流感疫苗不被批准用于儿童或老年人。因此，需要开发一种疫苗，像CAV一样，能够诱导异型免疫，并针对NALT和呼吸道。然而，对NALT的实际功能知之甚少，而且NALT在CAV免疫应答中的作用也从未被测试过。因此，这项建议的总体目标是专门评估鼻腔注射重组蛋白和冷适应流感病毒(CAV)在NALT中引发的免疫反应。我们将确定NALT是否启动了对CAV或蛋白质抗原的免疫反应，NALT中的启动是否赋予T细胞粘膜归巢特性，以及NALT中的T细胞是否启动到肺组织和呼吸道。我们还将确定对CAV的免疫反应是否会引发与鼻腔接种蛋白质疫苗在功能上不同的CD4T细胞。此外，我们将确定鼻内接种CAV或蛋白质抗原是否会诱导M2e特异性B细胞，这些B细胞是上呼吸道和下呼吸道的家园。我们还将测试CAV或重组蛋白的抗原如何传递到NALT中的淋巴细胞，M细胞是否参与这一过程，以及NALT中的M细胞是否与Peyer‘s Patches NALT中的M细胞相似。最后，我们将确定CAV或蛋白质抗原的鼻腔免疫是否会导致对强毒、异型流感毒株的长期免疫。与公共卫生相关：甲型流感病毒是人类的一种重要自然病原体，每年在美国平均导致3.5万人死亡。此外，特别强的流感病毒周期性地出现，并在一个季节导致数百万人死亡。这些新出现的流感病毒株，例如1997年在香港出现的高毒力H5N1变种，有可能引发另一场全球大流行，造成毁灭性的社会和经济后果。因此，我们必须开发对多种流感血清型具有保护作用的疫苗。这项建议描述了将确定鼻腔接种感冒适应病毒或纯化蛋白提高流感免疫力的机制的实验。这些信息将对开发促进对流感的持久交叉反应免疫的疫苗至关重要，流感病毒仍是一种新出现的传染病。

DESCRIPTION (provided by applicant): Cold adapted influenza vaccines (CAV) are live attenuated viruses that infect the upper respiratory tract, including the Nasal Associated Lymphoid Tissue (NALT). Since NALT is a mucosal lymphoid organ, it is presumed to direct the development of B and T cells that most effectively protect the respiratory tract. Despite the potential benefits of CAV influenza vaccines, the use of these vaccines to elicit immunity to zoonotic viruses, such as H5N1 avian influenza, is limited due to the fear of recombination between contemporary influenza strains and the vaccine strain. In addition, CAV influenza vaccines are not approved for children or the elderly. Thus, it is desirable to develop vaccines that, like CAV, can elicit heterotypic immunity and target the NALT and respiratory tract. However, the actual function of NALT is poorly understood and the role of NALT in immune responses to CAV has never been tested. Therefore, the overall goal of this proposal is to specifically evaluate immune responses in NALT elicited by intranasally delivered recombinant protein and cold-adapted influenza virus (CAV). We will determine whether immune responses to CAV or protein antigens are initiated in NALT, whether priming in NALT confers mucosal homing properties on T cells and whether T cells primed in NALT home to the lung tissue and airways. We will also determine whether immune responses to CAV elicit CD4 T cells that are functionally different than those elicited by nasal vaccination with proteins. Moreover, we will determine whether intranasal vaccination with CAV or protein antigens elicit M2e-specific B cells that home to the upper and lower respiratory tract. We will also test how antigens from CAV or recombinant proteins are delivered to lymphocytes in NALT, whether M cells are a part of this process and whether M cells in NALT are similar to those in Peyer's patches NALT. Finally, we will determine whether intranasal immunization with CAV or protein antigens results in long-lived immunity to virulent, heterotypic strains of influenza. Relevance to public health: Influenza A virus is a significant natural pathogen of man that is responsible for an average of 35,000 deaths annually in the US. In addition, particularly virulent influenza viruses periodically emerge and cause millions of deaths in a single season. These emerging strains of influenza, such as the highly virulent H5N1 variant that appeared in Hong Kong in 1997, have the potential to trigger another worldwide pandemic with devastating social and economic consequences. Thus, it is imperative that we develop vaccines that are protective against a wide array of influenza serotypes. This proposal describes experiments that will determine the mechanisms by which intranasal vaccination with cold adapted viruses or purified proteins promote immunity to influenza. This information will be essential for the development of vaccines that promote long-lasting cross-reactive immunity to influenza, a virus that continues to be an emerging infectious disease.