Expression of a V_HC_κ chimaeric protein in mouse myeloma cells

Abstract

The heavy (H) and light (L) chains of antibodies consist of variable (V) and constant (C) regions. The V regions of the heavy and light chains form the antibody combining site^1,2. To determine whether a V region could be functional when joined to a polypeptide other than its own C region, we constructed a chimaeric gene encoding the V region of a mouse heavy chain and the C region of a mouse κ light chain (V_HC_κ). The heavy-chain gene is derived from an A/J mouse hybridoma cell line 36-65 whose antibody product (γ1, κ) is specific for the hapten azophenylarsonate³. We report here that, when introduced into a mouse myeloma cell line, the chimaeric gene is expressed and a protein of the expected molecular weight is secreted into the medium. As light chains tend to dimerize^4,5 we expected that the V_HC_κ protein might associate with light chain from the cell line 36-65 to form an antibody-binding molecule. Affinity binding experiments and K_a determination indicate that this is the case. Dimers of this type offer a novel and interesting alternative to existing antibody-binding molecules.