IL-6 Production by Dendritic Cells Is Dispensable for CD8⁺ Memory T-Cell Generation

Figure 1

CD40-B cell and DC immunizations generate effectors expressing similar levels of IL-6R𝛼. (a) Expression of IL-6R𝛼 by OVA-specific Te cells at the peak of the T cell response (day 4). 10⁶ female OT-I T cells (CD8⁺CD45.2⁺) were adoptively transferred into congenic B6.SJL female mice (CD45.1⁺) followed by immunization two days later with 2×10⁶ LPS-matured unloaded CD40-B cells (CD40-B), LPS-matured CD40-B cells loaded with the OVA peptide (CD40-B OVA) or LPS-matured DCs loaded with the OVA peptide (DC OVA). The representative overlay histograms show expression of IL-6R𝛼 by OVA-specific Te cells (CD8⁺CD45.2⁺) and endogenous T cells (CD8⁺CD45.2⁻). The upper bold number indicates the mean fluorescence intensity (MFI) of OVA-specific Te cells while the lower number is for the endogenous CD8⁺ T cells. (b) Quantification of IL-6R𝛼 expression by effectors. The MFI of IL-6R𝛼 expression by effector CD8⁺ T cells (CD8⁺CD45.2⁺) was normalized to the MFI of the recipient CD8⁺ T cells (CD8⁺CD45.2⁻). Each dot represents one mouse. (c) CD40-B cells produce less IL-6 than DCs. Supernatants from CD40-B LPS or DC LPS culture were used to measure IL-6 secretion by ELISA. Mean ± SEM is shown for 3 independent experiments. *𝑃<0.05 and ***𝑃<0.001.

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