IMMUNOGLOBULIN SUBCLASSES: ROLES IN ACTIVITY OF IGIV AND IN ADVERSE REACTIONS

免疫球蛋白亚类：在 IGIV 活性和不良反应中的作用

• 批准号: 6293809
• 负责人: Basil Golding
• 金额: --
• 依托单位国家: 美国
• 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/6293809
• 关键词: AIDS vaccines; HIV envelope protein; HIV infections; Macaca mulatta; active immunization; antibody formation; helper T lymphocyte; host organism interaction; human immunodeficiency virus 1; human tissue; immunoglobulin idiotypes; immunoglobulins; laboratory mouse; mucosal immunity; neutralizing antibody; transport proteins

We have established that heat-killed Brucella abortus conjugated to a V3-loop peptide from HIV-1 MN can elicit neutralizing antibodies and CTL in normal and mice depleted of CD4+ T-cells, systemically and at mucosal surfaces. The antibodies elicited in mice lacking CD4+ T-cells were mainly of the IgG2a isotype. Sera from these mice were more efficient than sera containing predominantly IgG1 in neutralizing HIV-1. Furthermore this conjugate can induce neutralizing antibody (systemic and mucosal) and cellular responses in Rhesus macaques. Secretions from several mucosal sites including vagina exhibited ant-HIV neutralizing activity. Previously, we have shown that a strong Th1 stimulus, in the form of Brucella abortus, can switch Th2 to Th1 responses and inhibit IgE induction. These studies were performed in adult mice. Down-regulation of the Th2-like response induced by ovalbumin-alum (OVA/ALUM)by heat-killed Brucella abortus (BA) was not reversed by anti-IL-12 antibody treatment or in IFNg KO mice, suggesting that induction of Th1 cytokines was not the only mechanism involved in the BA-mediated inhibition of the Th2 response to OVA/ALUM. A study was performed to determine whether an alternative pathway involved alteration in expression of costimulatory molecules. B7.2, but not B7.1, was up-regulated on mouse non-T and T-cells following BA. Surprisingly, BA induced down-regulation of CD28 and up-regulation of B7.2 on murine CD4+ and CD8+ T cells. These effects on T-cells were maximal for CD28 and B7.2 at 40-48 h, and were not dependent on IL-12 or IFN-g. On the basis of these results we propose that the IL-12/IFNg- independent inhibition of Th2 responses to OVA/ALUM are secondary to the effects of BA on expression of costimulatory molecules on T cells. We suggest that down-regulation of CD28 following activation inhibits subsequent differentiation of Th0 into Th2 cells. In addition, decreased expression of CD28 and increased expression of B7.2 on T cells would favor B7.2 interaction with CTLA-4 on T cells and this could provide a negative signal to developing Th2 cells. Mouse IgG2a is a complement-fixing isotype. In order to study whether human complement-fixing antibodies are more potent in neutralizing virus, polyclonal antibody has been obtained from individuals with high titer against respiratory syncytia virus (RSVIG). This product was passed over protein A columns and purified into IgG3 and enriched for IgG2, IgG1 and IgG4. Further purifications will involve immunoaffinity columns. Preliminary data suggest that human IgG1 is more effective than IgG3 in neutralizing RSV.

我们已经确定，热灭活的流产布鲁氏菌与来自HIV-1 MN的V3环肽缀合，可以在正常和CD 4 + T细胞耗尽的小鼠中全身和粘膜表面引发中和抗体和CTL。 在缺乏CD 4 + T细胞的小鼠中引发的抗体主要是IgG 2a同种型。 来自这些小鼠的血清在中和HIV-1方面比主要含有IgG 1的血清更有效。此外，该缀合物可以在恒河猴中诱导中和抗体（全身和粘膜）和细胞应答。 包括阴道在内的几个粘膜部位的分泌物表现出抗HIV中和活性。 以前，我们已经表明，一个强大的Th 1刺激，在流产布鲁氏菌的形式，可以切换Th 2到Th 1的反应，并抑制IgE诱导。 这些研究在成年小鼠中进行。 热灭活牛种布鲁氏菌（BA）对卵清蛋白-明矾（OVA/ALUM）诱导的Th 2样应答的下调不被抗IL-12抗体处理或IFNg KO小鼠逆转，表明Th 1细胞因子的诱导不是BA介导的对OVA/ALUM的Th 2应答的抑制中涉及的唯一机制。进行了一项研究，以确定替代途径是否涉及共刺激分子表达的改变。BA后，B7.2在小鼠非T细胞和T细胞上上调，但B7.1未上调。 令人惊讶的是，BA诱导小鼠CD 4+和CD 8 + T细胞上的CD 28下调和B7.2上调。CD 28和B7.2对T细胞的这些作用在40-48小时达到最大，并且不依赖于IL-12或IFN-g。 在这些结果的基础上，我们提出，IL-12/IFNg非依赖性抑制Th 2对OVA/ALUM的应答是次要的BA对T细胞上共刺激分子表达的影响。 我们认为，下调CD 28活化后抑制随后的分化为Th 2细胞的Th 0。 此外，T细胞上CD 28表达的降低和B7.2表达的增加将有利于B7.2与T细胞上CTLA-4的相互作用，这可以为Th 2细胞的发育提供负信号。 小鼠IgG 2a是补体固定同种型。 为了研究人源补体结合抗体是否具有更强的中和病毒的能力，从人源获得了抗呼吸道合胞体病毒（RSVIG）的高效价多克隆抗体。 将该产物通过蛋白A柱，纯化为IgG 3，并富集IgG 2、IgG 1和IgG 4。 进一步的纯化将涉及免疫亲和柱。 初步数据表明，人IgG 1在中和RSV方面比IgG 3更有效。