Some Notes on the Rh-System – A Complex-Complex Model

. A new class of immunogenetic models is presented, which is based on the assumption of complex (cross-reacting) antibodies and complex antigens (i.e. antigens with more than one kind of antigenic determinants). The model is applied to the Rh-system at the 9 reagent-8 haplotype level and shown to give a simplified conceptual image of the Rh-system at this level. It is demonstrated that the same model could also have been deduced from a conventional (simple-complex) model if only the discovery of the 9 base reagents had occurred in a different historical sequence. Several experimental data which are difficult to accomodate in a conventional model appear strongly to support the new model, which also is in better harmony with the conceptual (but not notational) image of antibody-antigen relations expressed by many workers in the field. The new model only requires 5–6 symbols to account for those basic Rh-data which in a conventional simple-complex model would require 9–10 symbols. It is obvious that this new class of serologic models is also of great interest in other fields than immunogenetics.