Bone marrow macrophage (BMMF) response to IFNgR+FcgRI coincidence detection

Different cell types that make an organism use a small number of identical signaling modules to integrate external cues and elicit diverse functions. How the specificity of functional outcomes is achieved is unclear. It must lie within the context in which the external cue is perceived and integrated by the target cell. Within the innate immune system, we discovered communication between two classes of heterologous receptors designed to integrate external cues into context-specific response. Using IFNgR as an example, we describe the structural and functional collaboration between cytokine receptors and the ITAM signaling module, in this case the Fcg-chain at the plasma membrane of phagocytes. Receptor coupling allowed IFNg to modify FcgRI responses during IgG-mediated phagocytosis and to specify cell autonomous antimicrobial functions. BMMF were left unstimulated or were stimulated in duplicates for 6 hrs with IFNγ, IgG2a-opsonised SRBC or both. cDNA was analyzed using 8-sample Mouse Ref-8 v2.0 Illumina array. Expressed genes were defined as those with p<0.05, and their relative expression values were calculated using unstimulated cells as calibrator. IgG2a against SRBC was produced by hybridoma TIB111 from ATCC

构成生物体的不同细胞类型，仅通过少量保守的信号模块整合外部信号并触发多样化的细胞功能。目前学界尚未明确功能特异性结局的实现机制，其核心必然存在于靶细胞感知并整合外部信号的具体情境之中。在先天免疫系统中，我们发现两类异源受体之间存在通信机制，可将外部信号整合为情境特异性的应答反应。以干扰素γ受体（IFNgR）为例，本研究阐述了细胞因子受体与免疫受体酪氨酸激活基序（ITAM）信号模块（本研究中为吞噬细胞膜上的Fcγ链）之间的结构与功能协同作用。这种受体偶联使得干扰素γ（IFNγ）能够在IgG介导的吞噬过程中修饰FcγRI的应答，并特异性调控细胞自主的抗菌功能。本研究将骨髓源性巨噬细胞（BMMF）分为四组：未刺激对照组、分别以IFNγ、IgG2a包被的绵羊红细胞（SRBC）单独刺激组，以及二者联合刺激组，每组设置生物学重复两份，刺激时长均为6小时。随后采用8样本小鼠Ref-8 v2.0 Illumina微阵列对互补DNA（cDNA）进行检测分析。以未刺激细胞作为校准对照，将p<0.05的基因定义为差异表达基因，并计算其相对表达水平。靶向SRBC的IgG2a由美国典型培养物保藏中心（ATCC）的杂交瘤细胞株TIB111制备得到。