Fluorogenic probes for monitoring peptide binding to class II MHC proteins in living cells.
A crucial step in the immune response is the binding of antigenic peptides to major histocompatibility complex (MHC) proteins. Class II MHC proteins present their bound peptides to CD4(+) T cells, thereby helping to activate both the humoral and the cellular arms of the adaptive immune response. Peptide loading onto class II MHC proteins is regulated temporally, spatially and developmentally in antigen-presenting cells. To help visualize these processes, we have developed a series of novel fluorogenic probes that incorporate the environment-sensitive amino acid analogs 6-N,N-dimethylamino-2-3-naphthalimidoalanine and 4-N,N-dimethylaminophthalimidoalanine. Upon binding to class II MHC proteins these fluorophores show large changes in emission spectra, quantum yield and fluorescence lifetime. Peptides incorporating these fluorophores bind specifically to class II MHC proteins on antigen-presenting cells and can be used to follow peptide binding in vivo. Using these probes we have tracked a developmentally regulated cell-surface peptide-binding activity in primary human monocyte-derived dendritic cells.
Venkatraman
Prasanna
P
Department of Pathology, University of Massachusetts Medical School, 55 Lake Ave. North, Worcester, Massachusetts 01655, USA.
Nguyen
Tina T
TT
Sainlos
Matthieu
M
Bilsel
Osman
O
Chitta
Sriram
S
Imperiali
Barbara
B
Stern
Lawrence J
LJ
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology / Q000378:metabolism*; D001665:Binding Sites; D002478:Cells, Cultured; D018360:Crystallography, X-Ray; D005456:Fluorescent Dyes / Q000737:chemistry*; D000949:Histocompatibility Antigens Class II / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding / Q000276:immunology
D005456:Fluorescent Dyes; D000949:Histocompatibility Antigens Class II; D009842:Oligopeptides