Our Activmab technology enables the direct incorporation of multi-pass membrane proteins such as GPCRs and ion channels into the membrane of two antigenically distinct poxviruses. The protein of interest is correctly folded and expressed in the cell- derived viral membrane and does not require any purification before downstream use. Antigen expressing virus can be used for antibody selection using any in vitro display platform. Antigen virions can also be used for in vivo antibody discovery. Immunization with either viral strain produces potent antibody responses. The resulting immune cells can then be used for Single B Cell sorting, or to create an immunized phage library for in vitro panning.