AKNA, germinal center reaction and immunity.

体液免疫应答是由次级淋巴细胞免疫应答中富含T细胞的区域中的B细胞的活化引发的。 导致生殖中心（GC）前体进入次级卵泡的器官，在那里它们分化 进入记忆细胞。B细胞活化需要同源受体/配体相互作用，其中，B cetl- T细胞-CD 40配体（CD 154）介导的CD 40为细胞增殖、存活和B诱导提供了必要的刺激 细胞记忆体目前的研究集中在AT-钩蛋白AKNA，它是由生发中心B表达的。 淋巴细胞，结合CD 40和CD 154启动子的富含A/T的调控元件并调节其转录。在 与此观点一致，小鼠AKNA（moAKNA）也是由B和T淋巴细胞表达的核蛋白， 显示AT-钩DNA结合基序，上调CD 154并诱导CD 40的表达。统称 研究结果表明AKNA在GC内Ag依赖性应答的调节中起作用。具体目标是： 1.在体外评估AKNA在基因转录中的作用。使用小鼠模型，我们将确定moAKNA的 在CD 40、CD 154等基因靶点的表达中发挥作用。我们将研究moAKNA介导的 基因调控和评估其DNA结合的要求和特异性。2.为了检查moAKNA是否是 无论moAKNA在树突状细胞（DC）成熟和功能中是否起作用，moAKNA表达将 在体内Fit 3配体（FITL）依赖性DC动员和不同阶段特异性DC的分选后进行分析 子集我们还将检查AKNA表达是否随着抗原呈递细胞的获得而达到峰值。 (APC)表型和CD 40和CD 154的表达。在体内评估AKNA功能的意义。 将产生AKNA缺陷小鼠以阐明其在免疫应答中的功能。我们将研究 免疫后二次免疫应答的发展，检查共刺激分子的表达， 形成生发中心和产生抗体。淋巴结结构、细胞形态学分析 增殖、表型、CD 40和CD 154表达以及血清IG测定将评估是否存在或 缺乏功能性成熟B淋巴细胞库。DC成熟和它们刺激Ag中的T细胞的能力， 将检查CD 40/CD 154依赖性方式。胸腺内T细胞的分化、选择和它们的能力， 家次级卵泡和提供同源帮助将被测试。AKNA缺陷细胞的免疫功能将 在体内和体外检查它们响应Ag刺激、增殖、产生抗体和/或 细胞因子，响应存活/死亡信号，并产生免疫记忆。

Humoral immune responses are initiated by the activation of B cells in the T cell-rich areas of secondary lymphoid organs that lead to the recruitment of germinal center (GC) precursors into secondary follicles, where they differentiate into memory cells. B cell activation requires cognate receptor/ligand interactions, among which, the ligation of B cetl- CD40 by the T celI-CD40 ligand (CD154) provides the essential stimuli for cell proliferation, survival, and induction of B cell memory. The present study focuses on the AT-hook protein AKNA that is expressed by germinal center B- lymphocytes, binds to A/T-rich regulatory elements of CD40 and CD154 promoters and regulates their transcription. In keeping with this notion, mouse AKNA (moAKNA) is also a nuclear protein that is expressed by B and T lymphocytes, exhibits the AT-hook DNA-binding motifs, upregulates CD154 and induces the expression of CD40. Collectively these findings suggest that AKNA plays a role in the regulation of Ag-dependent responses within GCs. The specific aims are: 1. To assess in vitro the role of AKNA in gene transcription. Using the murine model, we shall determine moAKNA's role in the expression of CD40, CD154 and other gene targets. We shall study the mechanisms of moAKNA-mediated gene regulation and assess its DNA-binding requirements and specificity. 2. To examine whether moAKNA is expressed by dendritic cells (DC) and whether it plays any role in DC maturation and function, moAKNA expression will be analyzed following in vivo Fit3 ligand(FItL)-dependent DC mobilization, and sorting of distinct stage-specific DC subsets. We shall also examine whether AKNA expression peaks with the acquisition of the antigen presenting cell (APC) phenotype and the expression of CD40 and CD154.3. To assess in vivo the significance of AKNA's function. AKNA-deficient mice will be generated to elucidate its function in the immune response. We shall examine the development of secondary immune responses after immunization, examine the expression of costimulatory molecules, formation of germinal centers and antibody production. The histological analysis of lymphoid architecture, cell proliferation, phenotype, CD40 and CD154 expression, and determination of serum Ig will assess the presence or absence of functional mature B lymphocyte repertoires. DC maturation and their ability to stimulate T cells in an Ag and CD40/CD154-dependent manner will be examined. Intrathymic T cell differentiation, selection, and their capacity to home to the secondary follicles and provide cognate help will be tested. Immune functions of AKNA-deficient cells will be examined in vivo and in vitro for their capacity to respond to Ag stimuli, proliferate, produce antibodies and/or cytokines, respond to survival/death signaling, and develop immunological memory.