TY - JOUR
T1 - Identification of a human HLA-E-restricted CD8+ T cell subset in volunteers immunized with Salmonella enterica serovar Typhi strain Ty21a typhoid vaccine
AU - Salerno-Gonçalves, Rosângela
AU - Fernandez-Viña, Marcelo
AU - Lewinsohn, David M.
AU - Sztein, Marcelo B.
PY - 2004/11/1
Y1 - 2004/11/1
N2 - Our previous studies in volunteers immunized with Salmonella enterica serovar Typhi (S. Typhi) have suggested an important role for CD8+ T cells in host defense. In this study we describe a novel subset of neoclassical human HLA-E-restricted S. Typhi-specific CD8+ T cells derived from PBMC of Ty21a typhoid vaccinees. CD3+CD8+CD4 -CD56- T cells effectively killed S. Typhi-infected targets regardless of whether they share classical HLA class I molecules with them, by a FAS-independent, granule-dependent mechanism, as evidenced by induction of granzyme B release and the blocking effects of concanamycin and strontium ions. The expression of HLA-E Ags, bat not CD1-a, -b, or -c, OB the membrane of S. Typhi-infected targets rendered them susceptible to lysis. Moreover, anti-HLA-E Abs partially blocked these responses. We also demonstrated that presentation of S. Typhi Ags via HLA-E could stimulate lFN-γ production. Increases in the net frequency of IFN-γ spot-forming cells were observed in the presence of targets coated with peptides that contain S. Typhi GroEL HLA-E binding motifs. These results demonstrate that HLA-E binds nonamer peptides derived from bacterial proteins and trigger CD8 +-mediated lysis and IFN-γ production when exposed to infected targets, raising the possibility that this novel effector mechanism might contribute to host defense against intracellular bacterial infections.
AB - Our previous studies in volunteers immunized with Salmonella enterica serovar Typhi (S. Typhi) have suggested an important role for CD8+ T cells in host defense. In this study we describe a novel subset of neoclassical human HLA-E-restricted S. Typhi-specific CD8+ T cells derived from PBMC of Ty21a typhoid vaccinees. CD3+CD8+CD4 -CD56- T cells effectively killed S. Typhi-infected targets regardless of whether they share classical HLA class I molecules with them, by a FAS-independent, granule-dependent mechanism, as evidenced by induction of granzyme B release and the blocking effects of concanamycin and strontium ions. The expression of HLA-E Ags, bat not CD1-a, -b, or -c, OB the membrane of S. Typhi-infected targets rendered them susceptible to lysis. Moreover, anti-HLA-E Abs partially blocked these responses. We also demonstrated that presentation of S. Typhi Ags via HLA-E could stimulate lFN-γ production. Increases in the net frequency of IFN-γ spot-forming cells were observed in the presence of targets coated with peptides that contain S. Typhi GroEL HLA-E binding motifs. These results demonstrate that HLA-E binds nonamer peptides derived from bacterial proteins and trigger CD8 +-mediated lysis and IFN-γ production when exposed to infected targets, raising the possibility that this novel effector mechanism might contribute to host defense against intracellular bacterial infections.
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U2 - 10.4049/jimmunol.173.9.5852
DO - 10.4049/jimmunol.173.9.5852
M3 - Article
C2 - 15494539
AN - SCOPUS:6344269539
SN - 0022-1767
VL - 173
SP - 5852
EP - 5862
JO - Journal of Immunology
JF - Journal of Immunology
IS - 9
ER -