High-level and effective production of human mannan-binding lectin (MBL) in Chinese hamster ovary (CHO) cells

We have developed a high-expression system of recombinant human mannan-bind ing lectin (MBL) with CHO cells. Geneticin-resistant transformants harborin g human MBL cDNA in the expression vector pNOW/CMV-A were screened by immun oblot analysis for secretion of recombinant MEL. Cloning and selection by b oth geneticin and methotrexate resulted in the production of recombinant MB L to a final concentration of 128.8 mu g/ml in media after four days of cul ture. SDS-PAGE and gel-filtration analyses showed that recombinant MBL is c haracterized by two lower-order oligomeric structures (apparent molecular w eights: 1150 kDa and 300 kDa) compared to native MBL (apparent molecular we ight: 1300 kDa). The recombinant human MBL has both sugar-binding and compl ement activation activity and, like native MEL, can inhibit hemagglutinatio n of influenza A virus. Lectin blots with recombinant MBL indicate that it can bind such microorganisms as HIV and influenza virus suggesting that it might inhibit their infection of hosts. This high-level expression of human MBL with the full range of biological activity will be useful for studies on the immunological role of MBL in humans. (C) 1999 Elsevier Science B.V. All rights reserved.