[Detection of anti-Brucella spp. antibodies in swine by agglutination techniques and indirect ELISA in the Buenos Aires and La Pampa provinces, Argentina]. / Detección de anticuerpos anti-Brucella spp. en cerdos mediante técnicas de aglutinación y ELISA indirecto en las provincias de Buenos Aires y La Pampa, Argentina.

Porcine brucellosis is one of the most important zoonoses in this country. Currently, there is no control program for porcine brucellosis in Argentina and the epidemiological situation is still unknown. The purpose of our study was to detect anti-Brucella spp. antibodies in swine in the southwest of the Buenos Aires province and the east of the La Pampa province. Blood samples were obtained when animals were slaughtered. The presence of anti-brucella antibodies was studied by the buffered plate agglutination test (BPA), the tube agglutination test (SAT), the 2-mercaptoethanol (2-ME) agglutination test and indirect ELISA tests, using the cytosolic fraction from Brucella abortus S19 (CYT), and lipopolysaccharide (LPS)-free cytosolic proteins (CP). Out of a total of 325 samples analyzed, 17.8% reacted positively to BPA, 13.8% to SAT, 8.0% to 2-ME, 21.0% to ELISA-CYT and 10.0% to ELISA-CP. These results agree with the few data available in our country and suggest that brucellosis screening should be extended to other regions.

The grid-blot: a procedure for screening large numbers of monoclonal antibodies for specificity to native and denatured proteins.

This report describes a procedure referred to as a grid-blot for simultaneously testing up to 30 monoclonal antibodies for specificity with an equivalent number of different proteins on a single sheet of nitrocellulose paper. Only 150 microliters of hybridoma culture supernatant is required for the screening and the entire procedure can be completed in less than five hours. This assay was developed to quickly identify those hybridoma cultures producing antibodies that preferentially recognize the native form of a protein and those that also recognize the SDS denatured form and were optimal for use in Western blots. Monoclonal antibodies raised against two distinct proteins, myofibril C-protein (120 antibodies) and the catalytic subunit of cyclic-AMP dependent protein kinase (240 antibodies) were tested. The grid-blot results indicated that 85 of the C-protein antibodies and 55 of the catalytic subunit antibodies were monospecific. Only 4 of the C-protein and 9 catalytic subunit antibodies showed a preferential staining for the appropriate native protein. The antibodies that stained the denatured protein most intensely in the grid-blot corresponded with those that produced the best immunostain in the Western blot. Finally, a version of the grid-blot was found to be an efficient means of determining antibody isotypes.