Two sensitive assays for the detection of anti-Brucella antibodies.

A laser-nephelometric assay (LNA), applied to an adapted Wright's agglutination technique and an immunoenzymatic assay (ELISA) on tyndallised and sonicated Brucella are described. Both lead to an increased sensitivity of previous techniques for the detection of anti-Brucella antibodies. This was assessed in a) Brucellosis patients with either Wright and/or IF positive reactions (sero-positive) or Wright and IF negative reactions (sero-negative, ancient brucellosis). Positive results were obtained in all cases with a highly significant increase of the titers observed in "sero-positive" patients. b) Normal subjects with no previous history and no biological stigmata of brucellosis: most sera gave negative results - a very low incidence of weakly positive results were however evidenced. c) Subjects vaccinated with fraction PI: positive results were observed in all cases. They were much earlier detected with LNA or ELISA than with Wright's or IF tests and the ELISA or LNA titers of late "sero-positive" sera were 3 to 36 times higher than Wright's titers. d) Supernatants of anti-Brucella hydridomas: LNA and ELISA were both successfully applied to the screening of such supernatants.