Development and validation of a method for purification of mallein for the diagnosis of glanders in equines
1 Laboratório Nacional Agropecuário em Minas Gerais, Pedro Leopoldo, Brazil
2 Laboratório Nacional Agropecuário em Pernambuco, Recife, Brazil
3 Instituto Mineiro de Agropecuária, Belo Horizonte, Brazil
4 Departamento de Medicina Veterinária Preventiva, Escola de Veterinária - Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, Pampulha, Belo Horizonte, 31270-901, MG, Brazil
BMC Veterinary Research 2012, 8:154 doi:10.1186/1746-6148-8-154Published: 2 September 2012
The allergic test of mallein is one of the most frequently used tests, together with the Complement Fixation Test (CFT), for the diagnosis of glanders in endemic areas. Mallein, a purified protein derivative (PPD), is produced similarly to PPD tuberculin and the end product is a primarily proteic antigen, which is only poorly purified. The immuno-allergic activity of mallein is believed to be due to a high molecular weight group of proteins present in the antigen. To improve the quality of the antigen, in terms of sensitivity and specificity, a new method of mallein production was developed, in which purification was accomplished by ultrafiltration in a Tangential Flow Filtration system (TFF).
The TFF methodology efficiently separated the high and low molecular weight protein groups of mallein. The five TFF-purified malleins, produced from Burkholderia mallei strains isolated from clinical cases of glanders in Brazil, proved to be more potent than standard mallein in the induction of an allergic reaction in sensitized animals. Regarding specificity, two of the purified malleins were equivalent to the standard and three were less specific.
Some of the TFF-purified malleins showed considerable potential to be used as an auxiliary test in the diagnosis of glanders.