Terness P, Süsal C, Opelz G
Department of Transplantation Immunology, University of Heidelberg, Germany.
Immunobiology. 1992 Aug;185(2-4):303-13. doi: 10.1016/S0171-2985(11)80648-0.
Immunization of LEW rats with strongly histoincompatible BN blood cells induces, in addition to anti-donor antibody, a broadly reactive IgG autoantibody which binds to IgG and IgM molecules (IgG anti-Ig). Minute amounts of affinity purified IgG anti-Ig (0.2 pg/10(6) cells) suppress the antibody production in vitro of antigen receptor (AgR)-stimulated B cells derived from rats of the same strain. The suppressive antibody is also active in the whole serum IgG fraction. Importantly, anti-Ig-induced suppression is governed by restriction mechanisms: only AgR-occupied B cells are affected, the suppression is cell cycle dependent, and maximum suppression is obtained at an optimum IgG concentration. Treatment of rats in vivo with 0.8 mg Ig-anti-Ig (whole IgG fraction) along with allogeneic cells resulted in nearly complete suppression of the anti-donor antibody response. Possible mechanisms of B cell suppression by IgG anti-Ig are crosslinking of AgR with FcR, or cocapping of the two receptors with sterical interaction as a consequence of their separate occupation. Both alternatives lead to the release of an inactivating signal.
用组织相容性差异很大的BN血细胞免疫LEW大鼠，除了诱导产生抗供体抗体外，还会诱导产生一种广泛反应性的IgG自身抗体，该抗体可与IgG和IgM分子结合（IgG抗Ig）。微量亲和纯化的IgG抗Ig（0.2 pg/10⁶细胞）可在体外抑制来自同一品系大鼠的抗原受体（AgR）刺激的B细胞产生抗体。这种抑制性抗体在全血清IgG组分中也具有活性。重要的是，抗Ig诱导的抑制受限制机制支配：只有被AgR占据的B细胞受到影响，抑制作用依赖于细胞周期，并且在最佳IgG浓度下可获得最大抑制效果。用0.8 mg Ig-抗Ig（全IgG组分）与同种异体细胞一起对大鼠进行体内治疗，几乎完全抑制了抗供体抗体反应。IgG抗Ig抑制B细胞的可能机制是AgR与FcR交联，或者由于两个受体分别被占据而通过空间相互作用共帽化。这两种情况都会导致释放失活信号。
