Mycobacterium avium avium and Mycobacterium avium hominissuis give different cytokine responses after in vitro stimulation of human blood mononuclear cells

Background: Mycobacterium avium is the principal etiologic agent of non-tuberculous lymphadenitis in children. It is also a known pathogen for birds and other animals. Genetic typing of M. avium isolates has led to a proposal to expand the set of subspecies to include M. avium subsp. hominissuis. Isolates associated with disease in humans belong to this subspecies. Methodology/Principal Findings: Peripheral blood mononuclear cells from six healthy blood donors were stimulated in vitro with ten isolates of M. avium avium and 11 isolates of M. avium hominissuis followed by multiplex bead array quantification of cytokines in supernatants. M. avium hominissuis isolates induced significantly more IL-10 and significantly less IL-12p70, TNF, IFN-c and IL-17 when compared to M. avium avium isolates. All strains induced high levels of IL-17, but had very low levels of IL-12p70. Conclusion/Significance: The strong association between M. avium subsp. hominissuis and disease in humans and the clear differences in the human immune response to M. avium subsp. hominissuis compared to M. avium subsp. avium isolates, as demonstrated in this study, suggest that genetic differences between M. avium isolates play an important role in the pathogenicity in humans. Citation: Thegerström J, Jönsson B, Brudin L, Olsen B, Wold AE, et al. (2012) Mycobacterium avium Subsp. avium and Subsp. hominissuis Give Different Cytokine Responses after in vitro Stimulation of Human Blood Mononuclear Cells. PLoS ONE 7(4): e34391. doi:10.1371/journal.pone.0034391 Editor: Corinne Ida Lasmezas, The Scripps Research Institute Scripps Florida, United States of America Received May 25, 2011; Accepted March 2, 2012; Published April 10, 2012 Copyright: 2012 Thegerström et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: The study was supported by grants from the Medical Research Council of Southeast Sweden. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: [email protected]