CD4+ T cells recognize unique and conserved 2009 H1N1 influenza hemagglutinin epitopes after natural infection and vaccination.
Int Immunol
; 25(8): 447-57, 2013 Aug.
Article
en En
| MEDLINE
| ID: mdl-23524391
ABSTRACT
Influenza A/California/4/2009 (H1N1/09) is a recently emerged influenza virus capable of causing serious illness or death in otherwise healthy individuals. Serious outcomes were most common in young adults and children, suggesting that pre-existing heterologous immunity may influence the severity of infection. Using tetramers, we identified CD4(+) T-cell epitopes within H1N1/09 hemagglutinin (HA) that share extensive homology with seasonal influenza and epitopes that are unique to H1N1/09 HA. Ex vivo tetramer staining revealed that T cells specific for conserved epitopes were detectable within the memory compartment, whereas T cells specific for unique epitopes were naive and infrequent prior to infection or vaccination. Following infection, the frequencies of T cells specific for unique epitopes were 11-fold higher, reaching levels comparable to those of T cells specific for immunodominant epitopes. In contrast, the frequencies of T cells specific for conserved epitopes were only 2- to 3-fold higher following infection. In general, H1HA-reactive T cells exhibited a memory phenotype, expressed CXCR3 and secreted IFN-γ, indicating a predominantly Th1-polarized response. A similar Th1 response was seen in vaccinated subjects, but the expansion of T cells specific for HA epitopes was comparatively modest after vaccination. Our findings indicate that CD4(+) T cells recognize both strain-specific and conserved epitopes within the influenza HA protein and suggest that naive T cells specific for HA epitopes undergo significant expansion, whereas memory T cells specific for the conserved epitopes undergo more restrained expansion.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Vacunas contra la Influenza
/
Linfocitos T CD4-Positivos
/
Glicoproteínas Hemaglutininas del Virus de la Influenza
/
Gripe Humana
/
Epítopos
Tipo de estudio:
Prognostic_studies
Límite:
Adult
/
Humans
/
Middle aged
Idioma:
En
Revista:
Int Immunol
Asunto de la revista:
ALERGIA E IMUNOLOGIA
Año:
2013
Tipo del documento:
Article
País de afiliación:
Estados Unidos