1. fab antibodies Creative Biolabs is professional in producing Fab fragment antibodies using well established methods. We provide the most comprehensive list of Fab fragment antibodies. A Fab fragment is a special antibody which consists of four domains: VH, CH1, VL and CL1. The Fab fragment has 440-450 amino acids and its molecular weight is about 47-48 kDa. Compared with the full length antibodies, Fab fragments have some advantages. On one hand it is easy to penetrate tissues and can be generated by some simpler expression systems, such as E. coli. On the other hand, the Fab fragments lack Fc regions so that the interactions between Fc portions and Fc receptor will be removed. Therefore, the Fab fragments can enhance antibody specificity and reduce the effector functions. Fab fragment antibodies will become more and more important and popular. At present, there are three Fab fragment antibodies on the market, abciximab (ReoPro®), ranibizumab (Lucentis®) and certolizumab pegol (Cimzia®). Creative Biolabs scientists are also working hard to produce more and better Fab fragment antibodies to meet customer demand.