Role of LAIR-1 and CD300 Family Receptors in Regulating Inflammation

LAIR-1 和 CD300 家族受体在调节炎症中的作用

基本信息

批准号：
7732617
负责人：
John E Coligan
金额：
$ 48.17万
依托单位：
NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/7732617
关键词：
Affect Allergic Animals Antigens B-Lymphocytes CD4 Positive T Lymphocytes CD8B1 gene Cell surface Cells Chemical Models Collagen Cytoplasmic Tail Defect Dendritic Cells Development Family Family member Gene Cluster Goals Granulocyte-Macrophage Colony-Stimulating Factor HL60 Hematopoietic stem cells Human IRp60 ITAM ITIM IgG1 Immune Immune response Immunoglobulin Class Switching Immunologic Receptors In Vitro Inflammation Intracellular translocation Ligands Ligation Light Lymphocyte Lymphoid Mediating Modeling Mus Myeloid Cells Natural Killer Cells Numbers Organ Peptides Peripheral Peritoneum Peritonitis Play Production Proliferating Proteins Publishing Reactive Oxygen Species Receptor Activation Research Personnel Role Signal Transduction Site T-Lymphocyte cell type crosslink cytotoxicity eosinophil extracellular in vivo macrophage mast cell member monocyte neutrophil peripheral blood receptor research study response toll-like receptor 4 trafficking

项目摘要

We have generated LAIR-1 -/- mice on a B6 background to study the in vivo function of LAIR-1. Phenotypic analysis of lymphoid organs did not show large differences between LAIR-1 +/+ and LAIR-1 -/- animals. We have observed a slight increase in the percentage of splenic B cells in the LAIR-1 -/- mice, along with a decrease in T cells, mostly because of a decrease in CD8 T cells. This probably does not result from abnormal trafficking of T lymphocytes, since LAIR-1 +/+ and LAIR-1 -/- T cells traffic equally to peripheral lymphoid organs. In the gut we have observed a slight increase of T cells in the LAIR-1 -/- mice, along with an increase in the NKG2D expression. In vitro experiments showed that OT-II LAIR-1-/- CD4 T cells proliferated less than the OT-II LAIR-1+/+ CD4 T cells when they are cultured with APC loaded with OT-II OVA peptide. To study the immune response in vivo, we have immunized the animals with TNP-OVA and found that class switching is affected in LAIR-1 -/- mice. These animals produced lower levels of IgG2a and IgG2b, while switching to IgG1 is not affected. By using T cell specific LAIR-1 -/- animals (CD4 Cre LAIR-1flox/flox), we confirmed that the defect in class switching is T cell specific. Previous investigators have published that mouse B cells do not express LAIR-1; however, recently we have found that marginal zone B cells are positive for LAIR-1 expression. Other preliminary results have shown that in the LAIR-1 -/- mice there are significant alterations in the recruitment of macrophages and eosinophils into the peritoneum in a model of chemical peritonitis, suggesting a role for LAIR-1 in the trafficking of these cell types towards sites of inflammation. We showed that human neutrophils from peripheral blood express CD300a. To study expression during neutrophil development, we used the HL-60 differentiation model. We showed that CD300a expression is acquired during development and that cell surface expression increases very rapidly when neutrophils are stimulated with LPS and GM-CSF. This increase is the result of translocation of an intracellular pool of the receptor to the cell surface. This ready availability of CD300a is reminiscent of CTLA-4 and suggests that CD300a could play an important role in modulating neutrophil responses. Co-ligation of CD300a with the ITAM containing CD32a (FcRIIa) activation receptor inhibited CD32a mediated signaling, whereas it did not inhibit toll-like receptor (TLR)-4 mediated reactive oxygen species (ROS) production. Therefore, at least for human neutrophils, it seems that the inhibitory signals mediated by the CD300a receptor may be selective in their action.

我们已经在B6背景上产生了LAIR-1 - / - 小鼠，以研究Lair-1的体内功能。淋巴器官的表型分析并未显示Lair-1 +/ +和Lair-1 - / - 动物之间的巨大差异。我们已经观察到Lair-1 - / - 小鼠中脾B细胞百分比的百分比略有增加，以及T细胞的降低，主要是因为CD8 T细胞的降低。这可能不是由T淋巴细胞的异常运输引起的，因为Lair-1 +/ +和Lair-1 - / - T细胞同样流动到外周淋巴机构。在肠道中，我们观察到Lair-1/ - 小鼠中T细胞的略有增加，以及NKG2D表达的增加。体外实验表明，OT-II LAIR-1 - / - CD4 T细胞在用载有OT-II OVA肽的APC培养时，比OT-II Lair-1+/+ CD4 T细胞少于OT-II LAIR-1+/+ CD4 T细胞。为了研究体内的免疫反应，我们已经用TNP-ova免疫了动物，发现类切换在lair-1 - / - 小鼠中受到影响。这些动物产生了较低的IgG2a和IgG2B，而切换到IgG1的动物不受影响。通过使用T细胞特异性Lair-1-/ - 动物（CD4 CRE LAIR-1FLOX/FLOX），我们证实了类切换中的缺陷是T细胞特异性的。先前的研究人员已经发表了小鼠B细胞不表达巢穴-1。但是，最近我们发现边缘区B细胞对LAIR-1表达呈阳性。其他初步结果表明，在Lair-1 - / - 小鼠中，在化学腹膜炎模型中，巨噬细胞和嗜酸性粒细胞募集到腹膜中存在重大变化，这表明LAIR-1在将这些细胞类型贩运到炎症部位的运输中起作用。我们证明了外周血表达CD300A的人类嗜中性粒细胞。为了研究中性粒细胞发育期间的表达，我们使用了HL-60分化模型。我们表明，在发育过程中获得CD300A表达，并且当通过LPS和GM-CSF刺激中性粒细胞时，细胞表面表达的增加非常迅速。这种增加是将受体的细胞内池转移到细胞表面的结果。 CD300A的这种现成可用性让人联想到CTLA-4，这表明CD300A可以在调节中性粒细胞反应中发挥重要作用。与含有CD32A（FCRIIA）激活受体的ITAM共同结合CD32A介导的信号传导，而它没有抑制Toll样受体（TLR）-4介导的活性氧（ROS）产生。因此，至少对于人类嗜中性粒细胞，看来由CD300A受体介导的抑制性信号在其作用方面可能具有选择性。