B cell receptors and free antibodies have different antigen-binding kinetics.
Proc Natl Acad Sci U S A
; 120(35): e2220669120, 2023 08 29.
Article
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| MEDLINE
| ID: mdl-37616223
Since the pioneering works of Berg and Purcell, discriminating between diffusion followed by binding has played a central role in understanding cell signaling. B cell receptors (BCR) and antibodies (Ab) challenge that simplified view as binding to the antigen follows after a chain of diffusion and rotations, including whole molecule rotation and independent tilts and twists of their Fab arms due to their Y-shaped structure and flexibility. In this paper, we combine analytical calculations with Brownian simulations to derive the first-passage times due to these three rotations positioning the Fab paratopes at a proper distance and orientation required for antigen binding. Our results indicate that when measuring Ab-Ag effective kinetic binding rates, using experimental methods in which the analyte is in solution only gives values proportional to the intrinsic binding rates, [Formula: see text], and [Formula: see text], for values of [Formula: see text] up to [Formula: see text]. Beyond that, a plateau of the effective 3D on rate between [Formula: see text] and [Formula: see text] is attained. Additionally, for BCR-Ag interactions, the effective 2D on and off binding rates can only be inferred from the corresponding effective 3D on and off rates for values of effective 3D on rates lower than [Formula: see text]. This is highly relevant when trying to relate BCR-antigen-binding strength and B cell response, especially during germinal center reactions. Therefore, there is a pressing need to reexamine our current understanding of the BCR-antigen kinetic rates in germinal centers using the latest experimental assays for BCR-Ag interactions.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Receptores de Antígenos de Linfocitos B
/
Anticuerpos
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2023
Tipo del documento:
Article
País de afiliación:
España