INTERACTION OF HUMAN MANNOSE-BINDING PROTEIN WITH MYCOBACTERIUM-AVIUM

The interaction between human mannose-binding protein (MBP) and Mycoba cterium avium was explored, By ELISA, calcium-dependent and mannan-inh ibitable binding of human recombinant MBP (rMBP) to live M. avium was observed, Preincubation of M. avium with rMBP resulted in a 2-fold inc rease in uptake by human neutrophils. Mycobacterial cell wall componen ts were assessed by ELISA for their ability to bind the carbohydrate r ecognition domain of rMBP, The best ligand was mannosyl-lipoarabinoman nan, followed by lipomannan, phosphatidylinositol mannoside, arabinosy l-lipoarabinomannan, and dimycolated trehalose (cord factor), rMBP did not bind to partially purified lipid fractions containing glycopeptid olipids. These results are consistent with the known structural basis for rMBP ligand recognition, They suggest that MBP may play a role in host defense against M. avium by opsonizing both whole organisms and f ree cell wall components for internalization.