Severe Combined Immunodeficiency (SCID) mouse. Researcher holding a mouse with SCID, which will be used in scientific research. Mice with SCID were discovered in 1983 and are even more immunodeficient than nude mice, having no mature T or B cells. This is useful in cancer research as tumours from other species are easily transplanted into SCID mice and will grow without being rejected. In addition, SCID mice are ideal for the growth of hybridomas (cells that have been engineered to produce a desired antibody), necessary for a wide range of diagnostic, clinical and experimental procedures.