A panel of recombinant proteins for the serodiagnosis of caseous lymphadenitis in goats and sheep

Abstract

Summary Caseous lymphadenitis (CLA) is a small ruminant disease characterized by the development of granulomatous lesions in superficial and internal lymph nodes, as well as in some organs, and causes significant economic losses worldwide. The aetiological agent of CLA is the bacterium Corynebacterium pseudotuberculosis; however, the commercially available diagnostic tools present problems with regard to specificity, which can lead to false‐negative results. This study aimed to develop an indirect enzyme‐linked immunosorbent assay (ELISA) for the detection of specific immunoglobulins in goats and sheep using recombinant C. pseudotuberculosis PLD, CP40, PknG, DtxR and Grx proteins. For validation of the ELISAs, 130 goat serum samples and 160 sheep serum samples were used. The best ELISA for goats was developed using a combination of PLD and CP40 as antigens at a 1:1 ratio, which presented 96.9% sensitivity and 98.4% specificity. The most effective ELISA for sheep presented 91% sensitivity and 98.7% specificity when recombinant PLD alone was used as the antigen. These ELISAs can be used as highly accurate tools in epidemiological surveys and for the serodiagnosis of C. pseudotuberculosis infection in goats and sheep.

rSodC is a potential antigen to diagnose Corynebacterium pseudotuberculosis by enzyme-linked immunoassay

“…In the present study, the standardized test using rSodC protein showed satisfactory performance in the identi cation of positive and negative cases of C. pseudotuberculosis by serological responses, both in the initial standardization tests and in validation tests with goat and sheep samples. The use of this protein as an antigen to diagnose CL is promising due to the observed high sensitivity and speci city values, which were comparable or superior to those described in the literature to detect goats and sheep infected with C. pseudotuberculosis using different recombinant antigenic preparations (Menzies et al 2004;Rezende et al 2016;Barral et al 2019).…”

“…Currently, there are no reliable tests available to diagnose all CL cases. ELISA, using several antigenic preparations, has already been tested (Sutherland et al 1987;Menzies et al 1994;Sting et al 1998;Carminati et al 2003); however, few formulations use recombinant proteins (Menzies et al 1994;Rezende et al 2016; Barral et al 2019;Silva et al 2019). This strategy could signi cantly increase sensitivity and speci city due to the use of a single puri ed antigen (Rezende et al 2016).…”

rSodC is a potential antigen to diagnose Corynebacterium pseudotuberculosis by enzyme-linked immunoassay

“…As they are puri ed antigens, recombinant proteins can improve speci city, reducing the chances of cross reactions with molecules of other microorganisms. They can also in uence sensitivity, since the amount of immunodominant protein used to sensitize the plaques is greater than the concentration of this molecule in a raw antigen extract (Barral et al 2019).…”

“…In the rst validation step, recombinant SodC protein was selected to be tested with positive serum control samples from 50 goats and 45 sheep in which C. pseudotuberculosis infection was con rmed by isolating bacteria from caseous lesions. Samples from 50 goats and 45 sheep from CL nonendemic areas in southern Brazil, where there are strict controls for introducing new animals, were used as a negative control (Barral et al 2019).…”

“…Currently, there are no reliable tests available to diagnose all CL cases. ELISA, using several antigenic preparations, has already been tested (Sutherland et al 1987;Menzies et al 1994;Sting et al 1998;Carminati et al 2003); however, few formulations use recombinant proteins (Menzies et al 1994; Rezende et al 2016; Barral et al 2019;Silva et al 2019). This strategy could signi cantly increase sensitivity and speci city due to the use of a single puri ed antigen (Rezende et al 2016).…”