New and Rapid Strategies for the Diagnosis of Bovine Paratuberculosis ?in situ? Using Latex Particles

VERÓNICA D.G. GONZALEZ, M.N. ALONSO; V.S. GARCIA; R.D. MOYANO; M.A. ROMERO; L.M. GUGLIOTTA; G.E. TRAVERÍA; M.I. ROMANO

JOURNAL OF IMMUNOLOGICAL METHODS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2021 vol. 496

0022-1759

Chemical coupling of a protoplasmatic antigen from Mycobacterium avium subsp.paratubeculosis onto core-shell carboxylated particles was investigated with the aim ofproducing latex-protein complexes to be used in immunoagglutination assays able todetect bovine paratuberculosis disease. To this effect, sensitizations were carried outusing both colored and not colored carboxylated latexes, and the protoplasmaticantigen at pH close to its isoelectric point to favor the antigenic proteins approach tothe particles surface. In all cases, higher fractions of proteins were chemically-bound tocarboxyl groups on the particles surface. The performance of the visualimmunoagglutination assays produced was tested using a total of 111 sera fromhealthy and infected bovines with Mycobacterium avium subsp. paratuberculosis .Complexes obtained from the colored latex allowed an acceptable visual discriminationbetween the studied positive and negative sera. The sensitivity of the IA assaydeveloped was 70%, where most of the positive samples showed strong to very strongagglutination and only a few samples reacted weakly; and the specificity of the assaywas 86%. Therefore, this rapid detection technique allows an easy and inexpensiveidentification of animals possibly infected with paratuberculosis ?in situ? in the herds.