金山科研平台，产品价格货期咨询微信：jinshanbio Molecule Information: CD35 Aliases: C3BR; CD35; CR1; KN Entrez Gene IDs: 1378 (Human) Background: CD35 CD35, also known as complement receptor 1 (CR1), is an N-glycosylated member of the RCA (regulators of complement activation) family of proteins. The complement cascade plays an important role in the innate immune system through the recognition and clearance of immune complexes and foreign particles. There are four major allotypes of human CD35 which range from approximately 220 - 300 kDa. Mature human CD35 contains a 1930 amino acid (aa) extracellular domain (ECD) with 30 tandem SCR/SUSHI repeats, a 25 aa transmembrane segment, and a 43 aa cytoplasmic tail. A mouse ortholog of human CD35 has not been described, although alternate splicing of mouse CD21/CR2 generates a protein with homology to some SCR repeats of human CD35. A soluble form of the CD35 ECD circulates in the serum. Cell surface CD35 is widely expressed on hematopoietic cells. It cooperates with both CD21 and CR3/MAC-1 in the binding and internalization of particles and immune complexes that are opsonized with complement components C3b, C3i, and C4b. It also binds and internalizes particles opsonized with complement factor C1q or mannose binding lectin (MBL). CD35 protects the cell from complement-mediated lysis by serving as a cofactor for Factor I and inhibiting the C3 and C5 convertases. Erythrocyte-expressed CD35 mediates the hepatic clearance of complement-opsonized immune complexes. On lymphocytes, CD35 inhibits the activation-induced proliferation of T cells and B cells. Mice deficient in both CD21 and CD35 exhibit normal B cell development but severely compromised germinal center development, antibody production, and establishment of protective microbial immunity. In mice, CD21/CD35 must additionally be present on follicular dendritic cells to mount effective humoral responses and establishment of B cell memory.