A strategy for enhancing antigen specific LLPCs: Intraperitoneal immunization induces robust RSV specific B cell responses 2145

Abstract Description Long lived plasma cells (LLPCs) are a subset of antibody secreting cells (ASCs) that reside within the bone marrow and secrete high affinity, neutralizing antibodies for decades. Neutralizing antibody has traditionally served as the correlate of protection against many pathogens and is typically the primary goal in vaccine development. Vaccine induced germinal center (GC) responses can give rise to memory B cells (MBCs) and LLPCs however, the signals that control the differentiation of MCBs and LLPCs are not well understood. To this end, it is unclear how strategic vaccine design decisions can be made to promote LLPC generation and subsequent durable immunity. To address these questions, we investigated if IP immunization could induce more robust antigen specific B cells responses compared to IM immunization with the goal of increasing antigen specific LLPCs, which are known to be extremely rare. Using a trimeric pre-fusion stabilized RSV-F protein adjuvanted with alum as a model vaccine, we demonstrate that compared to IM immunization, IP immunization resulted in increased RSV-specific IgG, class-switched B cells and GC B cells within the spleens as well as RSV-specific antibody-secreting cells in both the spleen and bone marrow. IP immunization can therefore serve as a means of enhancing antigen specific B cell responses and LLPCs. Topic Categories Vaccines and Immunotherapy (VAC)