title: Serum amyloid P-component-mediated inhibition of the uptake of Mycobacterium tuberculosis by macrophages, in vitro.
abstract: The effect of purified mouse serum amyloid P-component (SAP) treatment of mouse alveolar macrophages (AMs) on their uptake of Mycobacterium tuberculosis Erdman was investigated, in vitro. SAP (0.5-50.0 micro g/ml), in a concentration-dependent manner, inhibited the M. tuberculosis uptake by the AMs; maximum inhibition (33.43%) occurred at 10.0 micro g/ml. The inhibition of uptake could be observed as early as 30 min after the incubation of AMs with 10.0 micro g/ml SAP; however, an incubation of 60 min induced maximum inhibition beyond which the response became static. The SAP-mediated decreased uptake of M. tuberculosis also resulted in their reduced intramacrophage growth as determined by colony-forming unit counts. SAP inhibited the uptake of mycobacteria in the presence of Ca(2+), and at pH = 5.6, the inhibition was abrogated. Deglycosylation of purified SAP with N-glycanase, and not with O-glycanase, blocked the SAP-mediated inhibition of the uptake. Heat-inactivated (80 degrees C; 1 h; pH 7.0) SAP did not inhibit the uptake of M. tuberculosis by AMs. These data, apparently for the first time, indicate that purified mouse SAP, in a divalent cation- and N-linked oligosaccharide glycosylation-dependent manner, inhibited the in vitro uptake of M. tuberculosis Erdman by mouse AMs, which was also associated with their reduced intracellular growth.
authors.affiliation: National Institute of Pharmaceutical Education and Research, S.A.S Nagar, Punjab, India.
authors.forename: S
authors.initials: S
authors.lastname: Kaur
authors.forename: P P
authors.initials: PP
authors.lastname: Singh
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D008264:Macrophages / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009169:Mycobacterium tuberculosis / Q000276:immunology* / Q000502:physiology; D010587:Phagocytosis / Q000187:drug effects; D000683:Serum Amyloid P-Component / Q000494:pharmacology*
chemical_list: D000683:Serum Amyloid P-Component