EXPRESSION STUDIES OF CATALYTIC ANTIBODIES

We have examined the positive influence of human constant regions on t he folding and bacterial expression of active soluble mouse immunoglob ulin variable domains derived from a number of catalytic antibodies. E xpression yields of eight hybridoma- and myeloma-derived chimeric Fab fragments are compared in both shake flasks and high-density fermentat ions. In addition the usefulness of this system for the generation of in vivo expression libraries is examined by constructing and expressin g combinations of heavy and light chain variable regions that were not selected as a pair during an immune response. A mutagenesis study of one of the recombinant catalytic Fab fragments reveals that single ami no acid substitutions can have dramatic effects on the expression yiel d. This system should be generally applicable to the production of Fab fragments of catalytic and other hybridoma-derived antibodies for cry stallographic and structure-function studies.