New Perspective on Innate Antibodies in Mice

项目摘要 目前对细菌刺激物如脂多糖（例如，乳过氧化物酶体系 来自酿脓链球菌鼠伤寒沙门氏菌）主要基于来自取自小鼠的脾细胞的体外刺激的数据。 未受刺激的小鼠然而，我们最近在体内小鼠模型中用LPS刺激的发现表明， 这些体外数据中的大部分不适合于模拟先天性反应，而先天性反应必然发生在体内。 同样，我们的研究结果提出了如何将体内模型（B细胞转基因，TLR缺陷， 寄生虫感染等）正常（基因完整）动物的LPS反应。 具体地说，我们发现，体内大部分LPS刺激的浆细胞反应是由B-1 a产生的 (CD5+ B-1）细胞，其中大部分仅在注射LPS后迁移到脾中。此外，我们发现， 体内对LPS的立即反应由驻留在脾中的B-1a细胞产生， 令人惊讶地在1-2天内分化成浆细胞而不经历细胞分裂。最初的一波 浆细胞分化占整体体内反应的相对小的比例， 并且主要由在分化为血浆之前（或同时）分裂的迁移B-1a细胞产生 细胞然而，早期反应者的快速反应能力， 免疫记忆，可能是关键的能力，使用先天免疫系统差距填补，直到 适应性免疫系统可以接管。 这里提出的研究旨在提供一个明确的观点，B细胞和机制，参与 对入侵病原体（包括但不限于LPS）的先天抗体应答。我们迄今为止的发现 证明我们可以有效地利用介导这些反应的微小功能性B细胞亚群 （分别为来自未刺激或LPS刺激的小鼠的0.1-3%的脾细胞）。因此，我们现建议 进一步明确区分常驻B-1应答和 这些移民B-1细胞，并确定在何种程度上，其他B细胞室和受体 相互作用有助于先天反应。总之，这些研究将为制定一项 涉及自然免疫的复杂先天免疫机制的全面和信息模型 必须迅速产生抗体反应，以最大限度地减少入侵病原体造成的损害。

Project Summary Current concepts of innate immune responses to bacterial stimuli such as lipopolysaccharides (e.g., the LPS from S. typhemurium used here) are largely based on data from in vitro stimulation of spleen cells taken from unstimulated mice. However, our recent findings with LPS stimulation in an in vivo mouse model demonstrate that much of this in vitro data is not suitable for modeling innate responses, which occur perforce in vivo. Similarly, our findings raise questions about the how to relate data from in vivo models (B-cell transgenic, TLRdeficient, parasite infection, etc.) to LPS responses in normal (genetically intact) animals. Specifically, we find that the majority of the LPS-stimulated plasma cell response in vivo is produced by B-1a (CD5+ B-1) cells, most of which only migrate into the spleen after LPS injected. Further, we find that the immediate response to LPS in vivo is produced by the B-1a cells that are resident in the spleen and surprisingly differentiate into plasma cells within 1-2 days without undergoing cell division. This initial wave of plasma cell differentiation accounts for a relatively small proportion of the overall in vivo response, which peaks at day 3 and is largely produced by immigrant B-1a cells that divide before (or while) differentiating to plasma cells. However, the rapid response capabilities of the early responders, which can be likened to primitive immunologic memory, may be key to the ability to use the innate immune system to ¿fill in the gap¿ until the adaptive immune system can take over. Studies proposed here are designed to provide a clear view of the B cells and mechanisms that participate in innate antibody responses to invading pathogens, including but not restricted to LPS. Our findings to date demonstrate that we can work effectively with the tiny functional B cell subsets that mediate these responses (0.1-3% of spleen cells from unstimulated or LPS-stimulated mice, respectively). Thus, we now propose to further define the cellular, anatomical and molecular mechanisms that distinguish resident B-1 responses from those of immigrant B-1 cells, and to determine the extent to which other B cell compartments and receptor interactions contribute to the innate response. Together, these studies will provide grounds for developing a comprehensive and informative model of the complex innate immunity mechanisms involved in natural antibody responses that must be produced rapidly to minimize damage due to invading pathogens.