TABLE 2.
Cytokine | Concn (pg/ml)a
|
|||||||
---|---|---|---|---|---|---|---|---|
Controlb
|
Y. enterocolitica
|
|||||||
SNc
|
Lysated
|
SN
|
Lysate
|
|||||
4–6 h | 24 h | 4 h | 24 h | 4–6 h | 24 h | 4 h | 24 h | |
IL-8 | 29 ± 2.4 | 218 ± 0.0 | <5 | <5 | 890 ± 10.3* | 897 ± 83.8* | <5 | <5 |
TNF-α | <15 | <15 | <15 | <15 | <15 | <15 | <15 | <15 |
IL-1α | <0.5 | <0.5 | <0.5 | <0.5 | <0.5 | <0.5 | 107 ± 12.5* | 52 ± 27.5* |
IL-1β | <1 | <1 | <1 | <1 | <1 | <1 | 26 ± 8.6* | 4 ± 5.4* |
MCP-1 | <10 | 141 ± 56.3 | <10 | <10 | 304 ± 18.3* | 817 ± 32.5* | 26 ± 12.8* | <10 |
GM-CSF | <2.8 | ND | <2.8 | ND | 137 ± 8.7* | ND | <2.8 | ND |
Mean ± standard deviation of triplicate samples from a representative experiment. *, statistically significant difference at P < 0.05. ND, not determined.
HeLa cells were exposed to medium (control) or Y. enterocolitica pYV− (MOI of 150) for 1 h. Cells were then washed with PBS, and medium containing gentamicin was added to kill extracellular bacteria.
Cytokine concentration in culture supernatant (SN) was measured by ELISA at the indicated times postinfection.
Cells were lysed as described in Materials and Methods after the indicated time points to determine intracellular cytokine concentrations by ELISA.