The year of Pasteur: from the concept of antibody and antigen by Bordet (1895) to the ELISA. What future for immunological diagnosis?
BACKGROUND
Chronological account of the increase of the sensitivity of immunological reactions and future possible improvements are presented.


RESULTS
During these 100 years, the sensitivity of immunological reactions has been increased by approximately 5 log by reference to the basic technique of quantitative immunoprecipitation.


OBJECTIVE
Future progresses can be foreseen (i) in the signal of labeled reagents, with the development of time-resolved fluoro-immunoassays; (ii) in the presentation of viral antigens on solid phase, with a larger use of polystyrene microbeads; (iii) in the antigen used for antibody detection, by promoting the characterization of antibodies to conformational structures of viruses; (iv) for antibody reagent preparations, particularly by immunomodulation for the development of antibodies to weak epitopes or to presently non-immunogenic structures and; (v) in the discrimination of detected antibodies. Characterization of the discontinuous or continuous nature of the recognized epitopes and of the affinity of antibodies could permit to date the infection. Inhibition of a monoclonal antibody reacting with a conformational epitope, and identification of an idiotope, will be more selective than the usual characterization of a large polyclonal antibody activity. Finally, the use of antibodies specific of the sole SIgA, molecule is expected to carry new informations in serological diagnosis at the entry of numerous infectious agents. ELISA techniques will become tightly complementary to PCR, which leads to an early diagnosis when the focus of infection is easily accessible, but rapidly looses its diagnosis capacity in acute infections.
Pillot
J
J
Unité d'Immunologie Microbienne, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.