Molecular interaction and enzymatic activity of macrophage migration inhibitory factor with immunorelevant peptides.
Disulfide reduction is an important step in antigen processing for HLA class II restricted T cell responses. Migration inhibitory factor (MIF) is a member of the thioredoxin family and has been classically defined as a cytokine. Using enzyme-linked immunosorbent assay and CD analysis, here we describe the binding to MIF of two peptides, hepatitis B surface antigen (HBsAg) and insulin B (InsB) with high affinity for HLA class II allo-types, HLA-DP2 and HLA-DQ8, respectively. At neutral pH, cysteinylated InsB was a substrate for MIF thiol reductase activity, as assessed by mass spectroscopy/electrospray analysis. Finally, a biologically active form of MIF co-immunopurified with mature forms of HLA DP2/15, and a peptide derived from the HLA-DP beta1 helix could be used for affinity purification of MIF. The possibility that MIF participates in class II antigen presentation and/or as a chaperone is discussed.
Potolicchio
Ilaria
I
Department of Molecular Cell Biology, Harvard University, Cambridge, Massachusetts 02138, USA. ipotolic@mcb.harvard.edu
Santambrogio
Laura
L
Strominger
Jack L
JL
D017951:Antigen Presentation / Q000276:immunology; D004220:Disulfides / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006514:Hepatitis B Surface Antigens / Q000378:metabolism*; D000949:Histocompatibility Antigens Class II / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008263:Macrophage Migration-Inhibitory Factors / Q000276:immunology / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism*; D011485:Protein Binding / Q000276:immunology; D013379:Substrate Specificity
D004220:Disulfides; D006514:Hepatitis B Surface Antigens; D000949:Histocompatibility Antigens Class II; D007328:Insulin; D008263:Macrophage Migration-Inhibitory Factors; D010446:Peptide Fragments; C097877:insulin B (9-23); D010088:Oxidoreductases