ACTIVATION AND TRIGGERING OF EFFECTOR CELLS

先天免疫的细胞介质不表达TcR，但在缺乏抗体的情况下具有识别和应答靶细胞的能力。在这个项目中，我们使用重定向裂解来证明一些粘附分子，包括CD38、CD44、CD56和CD69，有能力触发人类NK细胞和中性粒细胞的细胞毒性反应。然而，这些反应依赖于细胞因子，并且代表了直接识别致病物质的次要事件。最近，在人类和小鼠EST数据库中发现了一个古老的病原体识别受体家族，toll样受体（TLRs），其中两个TLR2和4被克隆并显示可触发对LPS的炎症反应。我们已经开始检测TLR在人类细胞中的表达，并在单核细胞、树突状细胞、NK细胞、T细胞和PMN中发现了几种容易检测到的TLR信息。单核细胞表达最高水平的TLR信息，这些水平在单核细胞向树突状细胞分化过程中降低。对TLR1的单抗对所有单核细胞都有强烈的染色，但对树突状细胞的染色水平较低。在293细胞中，TLR1和TLR2的共转染增强了TLR2对某些形式LPS的反应，但抑制了其他系统的反应。我们的首要任务是确定TLR的表达模式，然后研究免疫细胞和外周组织细胞中的TLR信号。为此，我们已经克隆了TLR1和5，并且正在克隆（或从其他人那里获得）其他tlr。我们的目的是培养针对每一种tlr的抗体，并用它们来研究蛋白质表达，并进行交联研究。对病原体的免疫反应始于先天系统对其的识别，导致炎症反应的发展。tlr很可能在这一过程中起着重要作用。重定向细胞毒性已在临床前小鼠模型中用于阻断肿瘤生长，但在晚期肿瘤生长经常导致T和B细胞反应的深度免疫抑制，从而降低了任何免疫治疗方法的有效性。我们最初表明，肿瘤生长也导致B细胞和T细胞区室中STAT5蛋白表达的选择性缺失，这可能导致对包括IL-2在内的几种细胞因子无反应。为了进一步了解免疫抑制，我们与恩佐·勃朗特博士合作，使用体外系统研究免疫抑制。Brontes小组最初发现免疫抑制是由抑制型巨噬细胞/树突状细胞在肿瘤生长后期侵入淋巴组织引起的，他使这些细胞永生。我们发现这些细胞在抗原、同种异体细胞和Con a的刺激下强烈地阻断T细胞的增殖。此外，增殖的抑制是由于诱导对IL-2的无反应性。早期的事件，如CD69和CD25的上调，以及诱导IL-2的分泌不会受到损害。无反应状态依赖于一氧化氮的产生。我们已经证明，由脾细胞产生的IFN-诱导抑制细胞产生一氧化氮，并且IFN-抗体和iNOS（诱导型一氧化氮合酶）抑制剂都阻断了非反应状态的诱导。无应答性并不伴随着STAT5 （a和B）表达的缺失——这种缺失发生在晚些时候，但STAT5的酪氨酸磷酸化明显降低。早期结果尚未检测到JAK3表达或磷酸化的变化。这些结果表明，巨噬细胞相关细胞中iNOS的诱导在决定细胞是否刺激或抑制免疫应答中起着关键作用，我们打算研究受到各种分化信号的巨噬细胞中的iNOS及其产物。-粘附分子，双特异性抗体，细胞毒性，免疫抑制，重定向细胞溶解，信号分子，先天免疫，-人体组织，液体，细胞等，非人体受试者和人体组织

Cellular mediators of innate immunity do not express TcR, yet have the capacity to recognize and respond to target cells in the absence of antibody. In this project we have used redirected lysis to demonstrate that a number of adhesion molecules, including CD38, CD44, CD56, and CD69, have the ability to trigger cytotoxic responses in human NK cells and neutrophils. These responses however are dependent upon cytokines, and represent events secondary to the direct recognition of pathogenic substances. Recently an ancient family of pathogen recognition receptors, the toll like receptors (TLRs) was discovered in human and mouse EST data bases, and two of these, TLR2 and 4 were cloned and shown to trigger inflammatory responses to LPS. We have begun examining TLR expression in human cells, and have found easily detectible message of several of the TLRs in monocytes, dendritic cells, NK cells, T cells and PMN. Monocytes express the highest levels of TLR message, and these levels decrease during differentiation of monocytes to dendritic cells. A mAb to TLR1 stains all monocytes strongly, but gives lower level staining on dentritic cells. Co-transfection of TLR1 with TLR2 in 293 cells potentiates the response of TLR2 to some forms of LPS, but inhibits the response in other systems. Our first priority is to determine the expression patterns of TLRs and then to study TLR signaling in immunocytes and in cells from peripheral tissues. Toward this end we have cloned TLR1 and 5, and are in the process of cloning (or obtaining from others) the other TLRs. Our intention is to raise antibodies to each of the TLRs, and to use them to study protein expression, and to do crosslinking studies. The immune response to a pathogen begins by its recognition by the innate system, resulting in the development of an inflammatory response. It is likely that the TLRs play a major role in this process.Redirected cytotoxicity has been used in preclinical mouse models to block tumor growth, but at late stages tumor growth frequently results in profound immunosuppression of both T and B cell responses, thus reducing the effectiveness of any immunotherapeutic approach. We originally showed that tumor growth also resulted in a selective loss in STAT5 protein expression in B and T cell compartments, which could lead to unresponsiveness to several cytokines including IL-2. To further our understanding of the immune suppression, we have, in collaboration with Dr. Enzo Bronte, used an in vitro system to study immunosuppression. Brontes group originally found that immunosuppression was induced by a suppressor type macrophage/dendritic cell that invades the lymphoid tissue at later stages of tumor growth, and he has immortalized these cells. We have found that these cells strongly block T cell proliferation in response to stimulation by antigen, allogeneic cells and Con A. Moreover, inhibition of proliferation is due to the induction of a non- responsiveness to IL-2. Earlier events, such as up regulation of CD69 and CD25, and induction of IL-2 secretion are not impaired. The non- responsive state is dependent on nitric oxide production. We have shown that IFN- , produced by splenocytes, induces the production of nitric oxide in the suppressor cells, and that antibody to IFN- and an inhibitor of iNOS (inducible nitric oxide synthase) both block the induction of the non-responsive state. Non-responsiveness is not accompanied by a loss in STAT5 (A and B) expression-that occurs later, but there is a marked reduction tyrosine phosphorylation of STAT5. Early results have not yet detected a change in JAK3 expression or phosphorylation. These results suggest that the induction of iNOS in macrophage-related cells plays a pivotal role in determining whether the cells will stimulate or suppress immune responses, and we intend to study iNOS and its product in macrophages that have been subjected to various differentiation signals. - Adhesion Molecules, bispecific antibodies, Cellular cytotoxicity, Immunosuppression, redirected cytolysis, signaling molecules, Innate Immunity, - Human Tissues, Fluids, Cells, etc. & Neither Human Subjects nor Human Tissues