Neutralization of Interleukin-10 from CD14⁺Monocytes Enhances Gamma Interferon Production in Peripheral Blood Mononuclear Cells fromMycobacterium aviumsubsp.paratuberculosis-Infected Goats

Abstract

The gamma interferon assay is used to identify Mycobacterium avium subsp. paratuberculosis-infected animals. It has been suggested that regulatory mechanisms could influence the sensitivity of the test when it is performed with cells from cattle and that the neutralization of interleukin-10 (IL-10) in vitro would increase the gamma interferon responses. To investigate the regulatory mechanisms affecting the gamma interferon assay with cells from goats, blood was collected from M. avium subsp. paratuberculosis-infected, M. avium subsp. paratuberculosis-exposed, and noninfected goats. Neutralization of IL-10 by a monoclonal antibody resulted in increased levels of gamma interferon production in M. avium subsp. paratuberculosis purified protein derivative (PPDj)-stimulated samples from both infected and exposed goats. However, the levels of gamma interferon release were also increased in unstimulated cells and in PPDj-stimulated cells from some noninfected animals following neutralization. Depletion of putative regulatory CD25 high T cells had no clear effect on the number of gamma-interferon-producing cells. The IL-10-producing cells were identified to be mainly CD14 ؉ major histocompatibility complex class II-positive monocytes in both PPDj-stimulated and control cultures and not regulatory T cells. However, possible regulatory CD4 ؉ CD25 ؉ T cells produced IL-10 in response to concanavalin A stimulation. The numbers of CD4 ؉ , CD8 ؉ , and CD8 ؉ ␥␦T-cell receptor-positive cells producing gamma interferon increased following IL-10 neutralization. These results provide insight into the source and the role of IL-10 in gamma interferon assays with cells from goats and suggest that IL-10 from monocytes can regulate both innate and adaptive gamma interferon production from several cell types. Although IL-10 neutralization increased the sensitivity of the gamma interferon assay, the specificity of the test could be compromised.

Mycobacterium avium ss paratuberculosis-associated Diseases

“…60 In addition, Th1/Th2 cytokine ratios were lower for CD patients than those observed for healthy control subjects when PBMNC were stimulated with MAP but not S. typhimurium. The skewed MAP-specific Th2 response in CD patients is consistent with that observed in cultures of chronically MAPinfected goat and cattle PBMNCs stimulated with MAP antigen in vitro under the influence of regulatory T cells 61,62 and favors intracellular MAP survival in macrophages.…”

Suppression of ovine lymphocyte activation by Teladorsagia circumcincta larval excretory-secretory products

“…To determine whether IL-10 signaling was involved in the observed effects, the impact of addition of the IL-10 neutralizing mAb, CC320 [ 34 , 35 ], on Tci -L4-ES-mediated suppression of Con A-induced proliferation was determined. The results are shown in Figure 6 .…”

The role of IL-10 in Mycobacterium avium subsp. paratuberculosis infection

“…IL-10 mediated suppression of IFN-γ secretion in peripheral blood of cattle and goats exposed to MAP infection is also documented [50, 51]. MAP stimulates IL-10 secretion from ovine and bovine monocytes derived antigen presenting cells [52–54].…”

“…IFN-γ is a key molecule that helps in the activation of macrophages with the production of reactive oxygen and nitrogen species, activation of T cells and maturation of DCs [76]. IFN-γ is the early marker of cell-mediated immune response and essential for effective clearance of the mycobacteria, but with the progression of disease, an immunosuppressive cytokine IL-10 becomes predominant [50, 51]. An enhanced host generated IFN-γ and IL-17A were observed in CBA/J mice during BCG vaccination resulted in additional protection against Mtb by inhibition of IL-10 activity through anti-IL-10R mAb treatment [77].…”