Acute-phase reactants during murine tuberculosis: Unknown dimensions and new frontiers - 17/08/11
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Summary |
Setting |
Serum amyloid P-component (SAP) plays important roles in host defense during various infectious diseases; however, nothing is known in tuberculosis (TB).
Objective |
To study the SAP response of Mycobacterium tuberculosis H37Rv- and H37Ra-infected mice, and to determine the effect(s) of purified mouse SAP both on their intra-alveolar macrophage (AM) uptake and intra-AM growth in vitro.
Design |
The SAP levels of mice intratracheally infected with M. tuberculosis H37Rv and H37Ra were determined by ELISA. Mycobacterial AM uptake and intra-AM growth in vitro were determined using fluorescence microscopy and plating, respectively.
Results |
M. tuberculosis H37Rv-infected mice showed significantly (p<0.05) increased SAP levels (352.8±36.1μg/ml) with compared mice infected with M. tuberculosis H37Ra (170±18.5μg/ml). During the acute phase of both these infections, enhanced SAP levels correlated with the lung mycobacterial load. In vitro, purified mouse SAP (1–80μg/ml) inhibited the AM uptake of both the mycobacteria in a concentration-dependent manners to a similar extent; 20μg/ml SAP appeared optimal. Mycobacterial uptake inhibition was divalent cation- and pH-dependent, and was unaffected both by heat-inactivated and deglycosylated SAP, separately. Curiously, purified mouse SAP (1–80μg/ml), in a concentration-dependent manner, inhibited the intra-AM growth of both M. tuberculosis H37Rv and H37Ra in vitro; the effect was 0.8log10 CFUs greater on the latter. Both the mannose-based simple sugars and rabbit anti-mouse SAP polyclonal antibody, separately, annulled the inhibition of mycobacterial growth in vitro.
Conclusion |
This initial study demonstrates that both the SAP response of M. tuberculosis-infected mice, and the SAP-induced intra-AM mycobacterial growth inhibition in vitro were apparently dependent on mycobacterial virulence.
Le texte complet de cet article est disponible en PDF.Keywords : Alveolar macrophage, Innate immunity, Mycobacterium tuberculosis, Pentraxin, Serum amyloid P-component
Plan
Vol 85 - N° 5-6
P. 303-315 - septembre 2005 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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