Stable Recombinant Expression and Functinal Identity of the Anti HIV-I Monoclonal Antibody 2F5 after IGG3/IGGI Subclass Switch in CHO-Cells

Abstract

The human monoclonal antibody 2F5 (Buchacher et al,, 1994) is a potent candidate for immunotherapy of HIV-1 (Katinger et al., 1995). The hybridoma derived humAb is of IgG3 kappa isotype. Since the IgG1 isotype has a longer half-life in human than IgG3, we switched the subclass-type to IgG1 by ligation of the 2F5 heavy chain variable region to an IgG1 constant region and expressed the IgG1 kappa molecule in CHO-cells. Stable recombinant 2F5-IgG1 expressing CHO-cells were isolated and the recombinant protein compared to the hybridoma derived immunoglobulin. Here we confirm, that specificity and affinity of different isotypes has not changed. Stability assays of the recombinant 2F5 IgG1 clone were performed with and without selection pressure.