Ross G D, Vĕtvicka V
Department of Microbiology and Immunology, University of Louisville, KY 40292.
Clin Exp Immunol. 1993 May;92(2):181-4. doi: 10.1111/j.1365-2249.1993.tb03377.x.
The C3 receptor CR3 is expressed on phagocytic cells, minor subsets of B and T cells, and natural killer (NK) cells. It has important functions both as an adhesion molecule and a membrane receptor mediating recognition of diverse ligands such as intercellular adhesion molecule-1 (ICAM-1) and fixed iC3b. The receptor is capable of undergoing an activation event that regulates both its specificity for various ligands and its ability to mediate phagocytosis or extracellular cytotoxicity. Certain bacteria express carbohydrates or lipopolysaccharides (LPS) that can bind to and activate CR3, allowing the receptor to assume its activated state. Soluble beta-glucan derived from the yeast Saccharomyces cerevisiae is a particularly potent stimulator of CR3, and produces an activated state of the receptor that permits neutrophil phagocytosis of iC3b-coated erythrocytes or NK, cell cytotoxicity of iC3b-coated tumour cells, that are normally resistant to NK cells.
补体C3受体CR3在吞噬细胞、少量B细胞和T细胞亚群以及自然杀伤（NK）细胞上表达。它作为一种黏附分子和膜受体具有重要功能，可介导对多种配体的识别，如细胞间黏附分子-1（ICAM-1）和固定的iC3b。该受体能够经历激活过程，这一过程会调节其对各种配体的特异性以及介导吞噬作用或细胞外细胞毒性的能力。某些细菌表达的碳水化合物或脂多糖（LPS）可与CR3结合并激活它，使受体进入激活状态。源自酿酒酵母的可溶性β-葡聚糖是CR3的一种特别有效的刺激物，可使受体进入激活状态，从而使中性粒细胞能够吞噬iC3b包被的红细胞，或使NK细胞对iC3b包被的肿瘤细胞产生细胞毒性，而这些肿瘤细胞通常对NK细胞具有抗性。
