Conformational analysis of human serum albumin and its non-enzymatic glycation products using monoclonal antibodies.

Monoclonal antibodies (mAbs) were prepared to analyse the conformation of human serum albumin (HSA) and its non-enzymatic glycation (NEG) products. We first determined the epitopes of the mAbs using HSA subdomains expressed on the surface of yeast. Each mAb was classified as belonging to one of two groups; Type I mAbs which recognized a single subdomain structure and Type II mAbs which bound to plural subdomains.

An optimized procedure for efficient phage display of antibody fragments with a low folding efficiency.

We recently developed an efficient bacterial expression system for phagemid-coded antigen-binding fragments of antibody (Fabs) without the use of a helper bacteriophage. This system is characterized by an unusually long cultivation at a low temperature and gentle induction of Fab expression without the addition of the inducer isopropyl-beta-D-thiogalactopyranoside (IPTG). This method allows for a high yield production of Fabs fused with phage gene III coat protein, even when the protein is defective in its folding ability.

Efficient bacterial production of functional antibody fragments using a phagemid vector.

The so-called 'in vitro evolutionary method' using a phage display system has been applied for protein engineering of the antigen-binding fragment of antibodies (Fab) by conducting random mutagenesis at the antigen-binding site in combination with antigen-based biopanning. However, isolated phage clones displaying Fab cannot necessarily be used for efficient bacterial production of engineered Fab proteins, often due to deleterious defects in their proper folding abilities derived in compensation for the gain of high affinity for a particular antigen. We here report a new method of an efficient and direct bacterial expression system for the phagemid-coded Fab proteins without use of the helper phage.

Initial repertoire of anti-(4-hydroxy-3-nitrophenylacetyl) antibodies as potential donors for effective affinity maturation.

We previously found that there are two distinct antibody (Ab) maturation pathways for the immune response of C57BL/6 mice to 4-hydroxy-3-nitrophenylacetyl (NP), one involving Abs with high evolvability (group-H) and the other involving Abs with low evolvability (group-L). Commitment to whichever pathway is followed pre-determined in B cells at an early developmental stage. Candidates for the group-L or -H pathway are thus expected to pre-exist in the initial repertoire of the immune response.