Cloning, expression, and modification of antibody V regions.

Cloned variable (V) regions of antibodies can be expressed joined to any constant (C) region, from either the same or a different species. The resulting antibodies will have the desired associated effector functions. Chimeric antibodies obtained by joining murine V regions to human C regions should have decreased immunogenicity in humans. The process of complementarity determining region (CDR) grafting, in which the CDRs from an antibody of one species are transferred to the framework regions of another species, constitutes a further modification of this approach. The protocols presented in this unit are designed to permit PCR-based cloning of heavy and light chain V regions. This is an advanced molecular biology protocol and should be employed only by investigators who are sufficiently skilled and experienced.