Memory CD8+ T cell responses expand when antigen presentation overcomes T cell self-regulation.
J Immunol
; 180(1): 64-71, 2008 Jan 01.
Article
en En
| MEDLINE
| ID: mdl-18097005
ABSTRACT
Antimicrobial memory CD8+ T cell responses are not readily expanded by either repeated infections or immunizations. This is a major obstacle to the development of T cell vaccines. Prime-boost immunization with heterologous microbes sharing the same CD8+ epitope can induce a large expansion of the CD8+ response; however, different vectors vary greatly in their ability to boost for reasons that are poorly understood. To investigate how efficient memory T cell expansion can occur, we evaluated immune regulatory events and Ag presentation after secondary immunization with strong and weak boosting vectors. We found that dendritic cells were essential for T cell boosting and that Ag presentation by these cells was regulated by cognate memory CD8+ T cells. When weak boosting vectors were used for secondary immunization, pre-established CD8+ T cells were able to effectively curtail Ag presentation, resulting in limited CD8+ T cell expansion. In contrast, a strong boosting vector, vaccinia virus, induced highly efficient Ag presentation that overcame regulation by cognate T cells and induced large numbers of memory CD8+ T cells to expand. Thus, efficient targeting of Ag to dendritic cells in the face of cognate immunity is an important requirement for T cell expansion.
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Banco de datos:
MEDLINE
Asunto principal:
Presentación de Antígeno
/
Linfocitos T CD8-positivos
/
Memoria Inmunológica
Límite:
Animals
Idioma:
En
Revista:
J Immunol
Año:
2008
Tipo del documento:
Article
País de afiliación:
Estados Unidos