Werther W A, Gonzalez T N, O'Connor S J, McCabe S, Chan B, Hotaling T, Champe M, Fox J A, Jardieu P M, Berman P W, Presta L G
Department of Immunology, Genentech, Inc., South San Francisco, CA 94080, USA.
J Immunol. 1996 Dec 1;157(11):4986-95.
Lymphocyte function-associated antigen 1 (LFA-1; CD11a/CD18) is involved in leukocyte adhesion during cellular interactions essential for immunologic responses and inflammation. mAbs against LFA-1 have been shown to inhibit several T cell-dependent immune functions in vitro and prevent graft failure after bone marrow transplantation in vivo. A murine anti-human CD11a mAb, MHM24, has been humanized and shown to prevent adhesion of human T cells to human keratinocytes and the proliferation of T cells in response to nonautologous leukocytes in the mixed lymphocyte response assay. However, of the nonhuman primate CD11a that we tested, the murine and humanized mAbs cross-reacted only with chimpanzee CD11a. To have a mAb available for preclinical studies in rhesus monkeys, the humanized mAb was reengineered to bind to rhesus CD11a by changing four residues in one of the complementarity-determining regions, CDR-H2, in the variable heavy domain. Cloning and molecular modeling of rhesus CD11a I-domain suggested that the changes from Lys197 and/or Arg189 in human CD11a I-domain to Glu197 and Gln189 in rhesus CD11a I-domain may be the reason that rhesus CD11a does not bind to the murine and humanized mAbs.
淋巴细胞功能相关抗原1（LFA-1；CD11a/CD18）在免疫反应和炎症所必需的细胞相互作用过程中参与白细胞黏附。抗LFA-1单克隆抗体已被证明在体外可抑制多种T细胞依赖性免疫功能，并在体内预防骨髓移植后的移植物衰竭。一种鼠抗人CD11a单克隆抗体MHM24已被人源化，并在混合淋巴细胞反应试验中显示可阻止人T细胞与人角质形成细胞的黏附以及T细胞对非自体白细胞的增殖反应。然而，在我们测试的非人灵长类动物CD11a中，鼠源和人源化单克隆抗体仅与黑猩猩CD11a发生交叉反应。为了获得一种可用于恒河猴临床前研究的单克隆抗体，通过改变重链可变区中一个互补决定区CDR-H2中的四个残基，对人源化单克隆抗体进行了重新设计，使其能够结合恒河猴CD11a。恒河猴CD11a I结构域的克隆和分子建模表明，人CD11a I结构域中的赖氨酸197和/或精氨酸189变为恒河猴CD11a I结构域中的谷氨酸197和谷氨酰胺189，可能是恒河猴CD11a不与鼠源和人源化单克隆抗体结合的原因。
