Evidence of a pro-apoptotic effect of specific antibodies in a bovine macrophage model of infection with Mycobacterium avium subsp. paratuberculosis

SILVIA HAJOS; SILVINA LOMPARDÍA; ANA JOLLY; SILVIA MUNDO

VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 169 p. 47 - 53

0165-2427

Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of Johne?s disease (JD), achronic granulomatous enteritis in ruminants. Understanding the protective immune response followinginfection is crucial to improve the diagnosis and the development of vaccines against this disease. The goalof this work was to assess whether specific antibodies were able to modulate the macrophage responseto MAP infection by evaluating apoptosis and TNF- secretion in an in vitro model. Sera from healthy(n = 2), MAP-infected (n = 3) and lipoarabinomannan (LAM)-immunized (n = 3) bovines were evaluated.LAM was chosen as immunogen due to its relevant role in mycobacterial pathogenesis. We demonstratedby two different techniques (Acridine Orange/Ethidium Bromide microscopy and Annexin V/7-Amino-Actinomycin D flow cytometry) that the immune sera from both, MAP-infected and LAM-immunizedbovines, significantly increased macrophage apoptosis in infected cultures. Comparable levels of apoptosiswere detected when MAP was pre-incubated with purified specific antibodies instead of wholeserum. Furthermore, this effect was accompanied by a significantly higher secretion of TNF-. Theseresults strongly suggest that specific antibodies could limit the impact of MAP on the apoptosis of bovinecells. This work would contribute to elucidate the role of the specific antibody response in bovine JD andits prevention.