Poor stimulation of bovine dendritic cells by Mycobacterium bovis cell surface sugar extract is associated with decreased proinflammatory signaling and higher expression of SOCS1 and 3
Vaccine and Infectious Disease Organization - International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
Olivia Ihedioha, Andrew Potter, Jeffrey Chen.
Bovine tuberculosis (bTB) caused by Mycobacterium bovis imposes major financial losses to the cattle industry via reduction of productivity, and also poses a danger to public health. M. tuberculosis cell surface antigens interact with host immune cells to enable pathogenesis. To address the effect of M. bovis cell surface antigens on the bovine immune system, we examined the effects of three different classes of M. bovis cell surface antigen fractions – purified protein derivative, total cell wall lipids and cell surface sugar extract (CSSE) on bovine dendritic cells (bDCs) which are key to controlling TB. We found the CSSE poorly induced proinflammatory responses in bDCs compared to the other fractions. Furthermore, the CSSE also increased the expression of SOCS1 and 3, which are negative regulators of proinflammatory signaling. Further analysis revealed that para-hydroxy benzoic acid derivative 1 (p-HBAD 1), a major constituent of CSSE exerts potent anti-inflammatory effects in bDCs. Taken together, these observations indicate that the M. bovis CSSE fraction and p-HBAD 1 present therein enables M. bovis to subvert host immune responses to cause disease.