TFH cells in bystander and cognate interactions with B cells.
Immunol Rev
; 288(1): 28-36, 2019 03.
Article
en En
| MEDLINE
| ID: mdl-30874359
ABSTRACT
Follicular T-helper (TFH ) cells play a crucial role in three aspects of the germinal center (GC) response. They promote GC formation, arbitrate competition among GC B cells to determine the outcome of affinity maturation, and regulate GC output of memory and plasma cells to shape the long-lived humoral immune memory. Of fundamental importance are dynamic physical interactions between TFH and B cells, which are the main platform for TFH cells to deliver "help" factors to B cells and also for reciprocal signaling from B cells to maintain the helper state of TFH cells. Recent work has significantly expanded our understanding of how T-B interactions are spatiotemporally regulated and molecularly orchestrated to fulfill those TFH functions. In this review, we elaborate two modes of T-B interactions, the antigen-specific or cognate mode in which TFH cells engage individual antigen-presenting B cells and the antigen nonspecific bystander mode in which TFH cells are engaged with the ensemble of follicular B cells. We discuss findings that indicate how short-lived cognate T-B contacts coupled with an intercellular positive feedback drive affinity-based selection and how bystander interactions between T and B cells regulate follicular T-cell recruitment and maintenance of an appropriate helper state. We argue that this combination of bystander and cognate interactions with B cells constantly shapes the internal state of TFH cells and provides the platform to execute their helper functions.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Linfocitos B
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Linfocitos T Colaboradores-Inductores
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Centro Germinal
Límite:
Animals
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Humans
Idioma:
En
Año:
2019
Tipo del documento:
Article