Diagnostic Usefulness of Antibodies Against Ribosome Recycling Factor from Brucella melitensis in Human and Canine Brucellosis

CASSATARO J,; DELPINO MV,; C A, VELIKOVSKI; BRUNO L,; CARLOS ALBERTO FOSSATI; BALDI PC,

CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY.

Karger

Año: 2002 vol. 9 p. 366 - 369

1071-412X

The diagnostic usefulness of an enzyme-linked immunosorbent assay (ELISA) using a purified recombinantribosome recycling factor from Brucella melitensis (CP24 antigen) was tested in human and canine infectionscaused by smooth and rough Brucella species, respectively. Anti-CP24 antibodies were detected in 9 (43%) of21 consecutive cases of canine brucellosis and in 8 (53%) of 15 dogs followed for 60 days after the diagnosis ofacute brucellosis. Among eight patients with acute brucellosis, anti-CP24 antibodies were detected in four inthe 10 weeks following diagnosis, but the remaining four were negative during the whole follow-up (22 weeks).The frequency of anti-CP24 antibodies was also low among 24 patients with subacute brucellosis and 23patients with chronic illness (29 and 26%, respectively). While all patients positive for anti-CP24 antibodieswere also positive for antibodies to total cytoplasmic proteins of Brucella (CP), five were negative for antibodiesto another cytoplasmic protein, the Brucella lumazine synthase (BLS). When a larger sample of 35 human seranegative for anti-BLS antibodies was assayed, 85.7% were positive for anti-CP24 antibodies, suggesting that thecombined measurement of both reactivities could yield a higher sensitivity than any test alone. To test thishypothesis, an ELISA combining both antigens was designed. The percentage of positive results among chroniccases was higher for this assay than for the individual measurement of anti-CP24 or anti-BLS antibodies (83versus 26 and 65%, respectively) and was closer to the value obtained for anti-CP antibodies (91%). Thefrequency of anti-CP24 antibodies is low in both canine and human brucellosis. In the latter case, however, anELISA combining CP24 and BLS is more sensitive than assays measuring anti-CP24 or anti-BLS antibodiesseparately and almost as sensitive as the ELISA using CP.