Transfer and expression of MHC genes

Monoclonal antibodies have extended our knowledge of the numerous cell-surface molecules which participate in T lymphocyte functions. However, how these molecules interact and function collectively is largely unknown. The histocompatibility antigens were the first of this set of molecules to be fully characterized at the DNA level. With DNA manipulation it is possible to alter a cloned gene in vitro so as to change any specific base in the sequence to any other base, to delete a given segment of the gene or to insert a new segment. Transfection into cells of normal or genetically engineered genes allows the relationships between the structure and the function of the protein products of these genes to be investigated. In this article, Bernard Malissen summarizes recent advances in the use of gene transfer and in-vitro directed mutagenesis techniques to dissect the behaviour of immunologically relevant molecules such as histocompatibility antigens.