Corynebacterium pseudotuberculosis: Immunological Responses in Animal Models and Zoonotic Potential

Abstract

Corynebacterium pseudotuberculosis is a member of the Corynebacterium, Mycobacterium and Nocardia (CMN) group that comprises species of medical, veterinary and biotechnological interest. This pathogen mainly affects small ruminants, causing caseous lymphadenitis (CLA), but it also infects bovines, equines, pigs, deer, camels and humans, showing its zoonotic relevance. Phospholipase D (PLD) and the toxic lipid cell wall are the two most wellstudied virulence factors of this bacterium. They are responsible, in part, for the establishment of disease in the host. Current knowledge on the immunity induced by C. pseudotuberculosis indicates that the resistance to infection is a complex process involving components of both the non-specific and specific host responses, in which humoral and cellular immune responses are both operative. Despite this knowledge and the importance of the disease, a satisfactory vaccine model for sheep and goats has not been developed. Moreover, a control program that includes an efficient diagnostic method in addition to vaccination is crucial for avoiding the spread of bacteria inside flocks. Further, because of its zoonotic potential, C. pseudotuberculosis infection of animals can contaminate meat and milk, putting consumers at risk. The ability of C. pseudotuberculosis to infect both animals and humans makes studies on prevention and diagnosis of this pathogen important.

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

“…Serological tests must have sensitivity and speci city > 90% to eliminate CL infections in large batches (O'Reilly et al 2010). A test of lower speci city may lead to falsepositive results, and decreased sensitivity may result in false-negatives (Carminati et al 2003;Bastos et al 2012).…”

“…The complete sequencing of the C. pseudotuberculosis genome, combined with the introduction of more advanced technologies, such as mass spectrometry, brought new perspectives to the study of proteins excreted by microorganisms as potential therapeutic, vaccine, or immunoassay targets (D'Afonseca et al 2010;Bastos et al 2012;Araújo et al 2019). Some of the highlighted immunoassay and vaccine development target proteins include diptheric toxin repressor homologue (DTxR), Trx and TrxR thioredoxin complex proteins, LexA proteins, superoxide dismutase-C (SodC), SpaC, neuraminidase H (NanH), and PknG serine/threonine kinases (Trost et al 2010;Hall et al 2011;Lin et al 2016;Santana-Jorge et al 2016).…”

“…Considering that the use of an e cient diagnostic method is crucial for the success of infectious disease control programs (Bastos et al 2012;Rezende et al 2016), and that extracellular or cell surface antigens allow for better recognition in ELISA tests (Oreiby 2015;Raynal et al 2018), the objective of this study was to evaluate C. pseudotuberculosis rDTxR, rTrx, TrxR, rLexA, rNanH, rSodC, rPknG and rSpaC proteins to develop a CL diagnostic test using serum from naturally and experimentally infected goats and sheep.…”

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

“…Considering that the use of an e cient diagnostic method is crucial for the success of infectious disease control programs (Bastos et al 2012;Rezende et al 2016), the objective of this study was to evaluate C. pseudotuberculosis rDTxR, rTrx, TrxR, rLexA, rNanH, rSodC, rPknG and rSpaC proteins to develop a CL diagnostic test using serum from naturally and experimentally infected goats and sheep.…”

Evaluation of the aroA mutant of Corynebacterium pseudotuberculosis in cellular and murine models

“…In infected horses, there are three clinical manifestations: subcutaneous or muscular abscess, mainly in the pectoral and abdominal regions; internal infection causing visceral abscess (liver, kidney, lungs, and spleen); and ulcerative lymphangitis, which results in limb inflammation, cellulitis and severe lameness 3 . To control this disease, several bacterins and live vaccines have been applied and found to exert partial protective effects 4 . The use of a bacterin-toxoid prepared with the phospholipase D exotoxin increased the antibody levels against exotoxin in sheep, reducing the number and size of the lesions relative to those in non-immunized animals 5 .…”