Historical note: past, present and future of the antiglobulin test.

This is a review of two invited talks on the antiglobulin reaction on the occasion of the 50th Anniversaries of the International Blood Group Reference Laboratory, now at Bristol, and the National Blood Service, London, and coincidentally the 51st anniversary of the antiglobulin test! The first talk (as specially requested) is a very personal reminiscence of the discovery, with Rob Race and Arthur Mourant, of the antiglobulin test in blood group serology. The second talk traces developments in antiglobulin testing in general immunology using, of course, isotype-specific antiglobulin reagents as and when they became available. Special emphasis was given to: (1) testing for poorly agglutinating bacterial antibodies; (2) special procedures for measuring reaginic (IgE) antibodies to various allergens; (3) the incorporation of an antiglobulin step or stage in many of the routine automated immunoassay procedures; (4) the special experimental procedures in the form of mixed antiglobulin reactions to reveal antibodies to the surface antigens on tissue cells, and, finally, (5) by chemically coupling antiglobulin to red blood cells, a distinctive integrated immunoassay system was developed, enabling reverse passive haemagglutination as an assay for immunoglobulins, rosetting reactions to reveal native IgG receptors on lymphocytes or antibody immunoglobulin reacting with CD marker antigens; this same reagent, namely red-cell-labelled antiglobulin, can be used to detect antibodies reacting with either bacteria or antigens adsorbed on the walls of wells of microtitre plates. The need for improved stabilization and preservation of the antiglobulin-linked red cells to prolong their 'shelf-life' is stressed.