Studying interactions involving the T-cell antigen receptor by surface plasmon resonance.
T-lymphocyte activation is initiated by the interaction of the alpha beta TCR with a complex consisting of a class I or class II MHC-encoded molecule and an antigenic peptide, displayed on the surface of an antigen-presenting cell. Real-time binding measurements using surface plasmon resonance have revealed kinetic and equilibrium parameters for the interactions between purified MHC molecules and peptides, between TCR and MHC-peptide complexes, and between TRC and superantigens. The MHC-peptide interaction is characterized by its high affinity and long half-life, the TCR-MHC/peptide interaction by its low affinity and short half-life, and the TCR-superantigen interaction by its low-to-moderate affinity, which is dependent on the particular superantigen involved. The consistent finding is that both MHC-peptide complexes and superantigens interact with TCR with a low affinity attributable to rapid dissociation. That an MHC-peptide complex that encounters a single TCR only briefly can still deliver the necessary activation signals offers a mechanistic conundrum for which several solutions have been proposed.
Margulies
D H
DH
Molecular Biology Section, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892-1892, USA. dhm@helix.nih.gov
Plaksin
D
D
Khilko
S N
SN
Jelonek
M T
MT
D000818:Animals; D015374:Biosensing Techniques; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D006801:Humans; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry* / Q000378:metabolism*
D011948:Receptors, Antigen, T-Cell