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: 6433598
• 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/6433598
• 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. To determine whether IgG subclasses differ in their ability to neutralize HIV-1, polyclonal HIVIG was passed over protein A columns and the appropriate fractions collected and shown to be > 89% pure IgG1, IgG2 and IgG3 (IgG4 was not present in sufficient quantities for study). All three subclasses showed binding to all major HIV-1 proteins (IgG1 >IgG2 > IgG3). In contrast, IgG3 was more active than other subclasses in its ability to neutralize HIV-1 as assayed by syncytia inhibition and cell- free virus neutralization (IgG3 > IgG1 > IgG2). The ability of HIVIG and the subclasses to neutralize viruses also depended on the virus strain, so that T cell tropic (R4) were more susceptible than Macrophage tropic (R5) viruses. IgG3 differs from IgG1 and IgG2 by virtue of a longer and more flexible hinge region. To test whether this is important in neutralizing virus, the IgG fractions will be digested by papain into Fc and Fab fragments and the Fab fragments tested for activity. These findings have implications for manufacture and clinical use of HIVIG. Moreover they suggest that HIV-1 vaccines should induce high titer IgG3 responses.

我们已经确定，热灭活的流产布鲁氏菌与 HIV-1 MN 的 V3 环肽缀合后，可以在正常小鼠和 CD4+ T 细胞耗尽的小鼠体内和粘膜表面引发中和抗体和 CTL。 在缺乏 CD4+ T 细胞的小鼠中引发的抗体主要是 IgG2a 同种型。 这些小鼠的血清在中和 HIV-1 方面比主要含有 IgG1 的血清更有效。此外，这种缀合物可以在恒河猴中诱导中和抗体（全身和粘膜）和细胞反应。 包括阴道在内的多个粘膜部位的分泌物表现出抗 HIV 中和活性。 为了确定 IgG 亚类中和 HIV-1 的能力是否存在差异，将多克隆 HIVIG 通过 Protein A 柱，收集适当的级分，结果显示 IgG1、IgG2 和 IgG3 的纯度 > 89%（IgG4 的数量不足以进行研究）。所有三个亚类均显示与所有主要 HIV-1 蛋白结合（IgG1 > IgG2 > IgG3）。 相反，通过合胞体抑制和无细胞病毒中和测定，IgG3 中和 HIV-1 的能力比其他亚类更活跃（IgG3 > IgG1 > IgG2）。 HIVIG 及其亚类中和病毒的能力也取决于病毒株，因此嗜 T 细胞病毒 (R4) 比嗜巨噬细胞病毒 (R5) 更容易受到影响。 IgG3 与 IgG1 和 IgG2 的不同之处在于具有更长且更灵活的铰链区。 为了测试这对于中和病毒是否重要，IgG 片段将被木瓜蛋白酶消化成 Fc 和 Fab 片段，并测试 Fab 片段的活性。 这些发现对 HIVIG 的生产和临床使用具有重要意义。此外，他们认为 HIV-1 疫苗应该诱导高滴度 IgG3 反应。