Since 1970, immunological research evolved from a polyspecies to a monospecies science, the latter based on laboratory strains of Mus musculus. The successful evolutionary rise of the laboratory mouse parallels the relative extinction of research on other mammals to the extent that textbook concepts are based almost entirely on studies in mice and humans.

This mini-review examines the validity of this monospecies approach by reviewing a single immunological concept; mammalian B cell and antibody repertoire development.  While the genomic organization of loci, the conserved structure and genetics of Igs like IgM and IgE and the retention of many similar lymphoid tissues appear universal, others are liberally diverse. These include the: (a) mechanisms used in developing the B-cell repertoire, (b) diversification of IgG into subclasses, (c) expression and structure of IgD, (d) role of the thymus in B-cell development, (e) functional and structural diversity of hind gut lymphoid tissues and (f) use of light chains. Since many of these differences/similarities among mammals are inconsistent with phylogeny, they suggest that regulation my be more important than genetic organization and constitution. While the mouse model has made extraordinary contributions to immunology, caution is needed in applying the concepts and paradigms developed from studies in mice to all mammals. The safest “model” is always the species that you want to study. This review therefore asks the broader questions of whether the “models” chosen for immunological research generate global concept(s) or species-specific concepts?