Class II Processing and Presentation During Secondary Responses to Influenza

流感二次反应期间的 II 类处理和呈现

• 批准号: 8823195
• 负责人: Laurence Crane Eisenlohr
• 金额: $ 29.4万
• 依托单位: THOMAS JEFFERSON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8823195
• 关键词: Animals; Antigen Presentation; Antigen-Presenting Cells; Antigenic Variation; Antigens; Attention; B-Lymphocytes; Binding; Biological Assay; CD4 Positive T Lymphocytes; Cell surface; Dendritic Cells; Engineering; Epitopes; Exposure to; Genetic Recombination; Helper-Inducer T-Lymphocyte; Histocompatibility Antigens Class II; Host Defense; Human; Hybridomas; Immune response; In Vitro; Infection; Influenza; Laboratory Study; Link; MHC Class II Genes; Mediating; Memory; Memory B-Lymphocyte; MicroRNAs; Modeling; Nature; Outcomes Research; Participant; Peptides; Play; Process; Reagent; Receptors, Antigen, B-Cell; Role; Shapes; Site; Specificity; Staging; Surface; Tamoxifen; Techniques; Testing; Vaccine Design; Virus; antigen processing; base; cell type; experience; extracellular; flu; in vivo; influenzavirus; lymph nodes; mouse model; pathogen; pathogen exposure; protein expression; public health relevance; response; targeted sequencing; trafficking

DESCRIPTION (provided by applicant): Activation of naive CD4+ T cells (TCD4+) is driven by MHC class II (MHCII)-bound peptides (epitopes) displayed at the surfaces of dendritic cells (DCs) that have trafficked from sites of infection to regional lymph nodes. While most studies concentrate on the primary response, the majority of pathogen exposures in nature are repeat encounters that play out in decidedly different contexts. Indeed, we hypothesize that activation of memory TCD4+, increasingly appreciated as a key aspect of the recall response, is fundamentally distinct. This is attributable in large part to the presence of antigen-specific B cells, which possess unique antigen processing capabilities. Consequently, this drives a significant shift in the TCD4+ specificities that emerge from recall vs. primary responses. Through well-established influenza models that play to the experience of both co-PIs, this hypothesis will be pursued via two tightly linked specific aims. In the first aim the impact of B cells in the secondary response will be assessed by: a) selectively eliminating or turning on MHCII on memory B cells prior to a secondary challenge, and b) restricting flu protein expression to specific cell types by engineering viruses that contain selective miRNA targeting sequences. In the second aim the antigen processing and presenting capabilities of ex vivo flu-specific B cells vs. DCs will be assessed by in vitro TCD4+ activation assays. The prediction is that the observed differences between these antigen presenting cell (APC) types will provide a basis for the TCD4+ specificities that are amplified during the secondary vs. primary responses. This project is expected to set the stage for studies that explore the processing machinery that facilitates B cell-mediated presentation, the role of memory B cells in responses to other pathogens, as well as more applied studies that leverage resulting principles to enhance rational vaccine design.

描述（由申请人提供）：幼稚CD 4 + T细胞（TCD 4+）的激活是由树突状细胞（DC）表面展示的MHC II类（MHCII）结合肽（表位）驱动的，这些细胞从感染部位运输到局部淋巴结。虽然大多数研究都集中在初级反应上，但自然界中的大多数病原体暴露都是在完全不同的环境中重复遭遇的。事实上，我们假设，激活的记忆TCD4+，越来越多的赞赏作为一个关键方面的回忆反应，是根本不同的。这在很大程度上归因于抗原特异性B细胞的存在，它们具有独特的抗原加工能力。因此，这驱动了回忆与主要反应中出现的TCD4+特异性的重大转变。通过完善的流感模型，发挥两个共同PI的经验，这一假设将通过两个紧密联系的具体目标。在第一个目标中，通过以下方式评估B细胞在二次应答中的影响：a）在二次攻击之前选择性地消除或开启记忆B细胞上的MHCII，和B）通过工程化含有选择性miRNA靶向序列的病毒将流感蛋白表达限制于特定细胞类型。在第二个目的中，将通过体外T ⑶ 4+活化测定来评估离体流感特异性B细胞相对于DC的抗原加工和呈递能力。预测是，这些抗原呈递细胞（APC）类型之间观察到的差异将为在二次应答与一次应答期间扩增的TCD4+特异性提供基础。该项目预计将为探索促进B细胞介导的呈递的加工机制、记忆B细胞在对其他病原体的反应中的作用以及利用所得原理来增强合理疫苗设计的更多应用研究奠定基础。