Synergistic combinations of chimeric anti-SEB: Engineering anti-toxins

描述(由申请人提供)：嵌合抗SEB的协同组合：工程抗毒素葡萄球菌肠毒素B(SEB)是一种超抗原，可导致食物中毒和中毒性休克综合征。SEB的生物活性来源于它能够同时与V2亚家族中T细胞的抗原提呈细胞和TCR结合，从而非特异性地激活大量的T细胞。抗体可以通过阻断这两个部位中的任何一个来中和这些毒素。这些研究源于一种假设，即针对不同和空间分离的中和表位的抗体组合将发挥协同作用。这项研究的抗体将通过筛选天然SEB免疫的Balb/C小鼠产生的抗SEB杂交瘤的文库来获得。筛选策略将识别两组中和抗体，其中一组识别SEB的TCR结合部位的表位，第二组与毒素的MHC-II结合部位的决定簇反应。将测试这些组中每个组的非交叉反应成员的组合，以确定哪些发挥协同作用。最强中和结合的每个成员的VH和VL区域将被克隆并嫁接到编码人IgG1CH(小鼠VH)和人Ig：CL(小鼠VL)的序列。嵌合的人-鼠抗体预计在临床应用中产生的Hama反应要少得多，将通过比较嵌合的SET及其成员与其对应的小鼠的中和活性来评估该嵌合体。该方案有以下具体目的：1.产生针对SEB的MHC结合部位的中和抗体，并获得针对TCRβ结合部位的中和抗体。2.鉴定针对SEB不同表位的中和抗体，并确定这些抗体的组合是否协同抑制SEB。3：将协同作用最强的中和抗体的每个成员的VH和VL结构域嫁接到人的CH和CL骨架上。协同抑制SEB的抗体组合可能有两个重要的实用优势，如果它们在临床环境中应用的话。首先，它应该更便宜，因为与单一的单抗相比，它需要的剂量要少得多。其次，能够用较少的抗体达到同等的治疗效果，应该会减少副作用的发生率和强度。葡萄球菌肠毒素B(SEB)可引起食物中毒和中毒性休克综合征。抗体可以中和SEB，这项研究是在以下假设的指导下进行的，即针对不同中和位点的鼠单抗组合将发挥协同作用。最有效组合的人-鼠嵌合形式将被设计成产生对人类更好耐受的抗体。

DESCRIPTION (provided by applicant): Synergistic combinations of chimeric anti-SEB: Engineering anti-toxins Staphylococcal enterotoxin B (SEB) is a superantigen that causes food poisoning and toxic shock syndrome. The biological activity of SEB arises from its ability to nonspecifically activate large numbers of T cells by simultaneously binding to the MHC-II on antigen presenting cells and TCRs of T cells belonging to a subset of V2 subfamilies. Antibodies can neutralize these toxins by blockading either of these sites. These studies arise from the hypothesis that combinations of antibodies targeting different and spatially separated neutralizing epitopes will act synergistically. The antibodies for this study will be obtained by screening a library of anti-SEB hybridomas generated from Balb/C mice immunized with native SEB. The screening strategy will identify two groups of neutralizing antibodies, one of which recognizes epitopes in the TCR- binding site of SEB and a second group that reacts with determinants in the MHC-II binding site of the toxin. Combinations of noncrossreactive members of each of these groups will be tested to determine which act synergistically. The VH and VL regions of each of the members of the most potent neutralizing combination will be cloned and grafted to sequences encoding the human IgG1CH (mouse VH ) and human Ig:CL (mouse VL ). The chimerized human-mouse antibodies which would be expected to produce much less HAMA reaction in clinical applications will be evaluated by comparing the neutralization activity of the chimeric set and its members with that of its mouse counterparts. The proposal has the following specific aims: 1. Generate neutralizing antibodies against the MHC binding site of SEB and derive neutralizing antibodies specific for the TCR beta binding site. 2. Identify neutralizing antibodies specific for different epitopes of SEB and determine if combinations of these antibodies synergistically inhibit SEB. 3: Graft the VH and VL domains of each member of the most potent sets of synergistically acting neutralizing antibodies onto human CH and CL frameworks. Combinations of antibodies that synergistically inhibit SEB may have two important practical advantages should they see application in a clinical setting. First, it should be less expensive because much smaller amounts would be needed than with single monoclonal antibodies. Second, the ability to achieve an equivalent therapeutic result with smaller amounts of antibody should decrease the incidence and intensity of side effects. Staphylococcal enterotoxin B (SEB) can cause food poisoning and toxic shock syndrome. Antibodies can neutralize SEB and this study is guided by the hypothesis that combinations of mouse monoclonal antibodies targeting different neutralizing sites will act synergistically. Chimeric human-mouse forms of the most effective combinations will be engineered to produce antibodies that will be better tolerated in humans.