Single B cell isolation and cloning from rabbits to generate recombinant antibodies

Abstract

For decades the method for generating antibodies with high avidity and affinity relied upon monoclonal antibody generation from immunized mice or polyclonal antibodies from rabbits. Both methods have their shortcomings. The murine immune system—specifically the high degree of immunological tolerance—prevents robust humoral responses to antigens that closely reasonable self-antigens in the mouse. Additionally, the cost and time necessary to generate a monoclonal antibody from mice can be prohibitively expensive, particularly if multiple attempts at hybridoma generation are required. A work around is to generate polyclonal antibodies in rabbits. Rabbits are further evolutionarily removed from humans than mice and mount a stronger immunological response to immunized human proteins or antigens. Unfortunately, the source of polyclonal antibodies from each rabbit is finite. To combat this problem, here we describe the development of a method to isolate single rabbit plasma B cells after immunization. Once isolated the VH and VL regions of the antibody are sequenced and the sequences are cloned into a recombinant rabbit IgG and IgK backbone that enables the recombinant expression of the single cell-derived, cloned rabbit antibodies. In doing so we have harnessed the immunological response of the rabbit host while eliminating the supply problem of finite reactive serum volumes and the cost of traditional murine monoclonal antibody generation.