Fig. 3

C-terminally truncated CXCL10_(1–73) has less potent signaling and chemotactic capacity in CXCR3A-transfected CHO cells and T lymphocytes. A CXCL10_(1–77) and CXCL10_(1–73) were evaluated for their ability to induce an increase of the intracellular calcium concentration ([Ca²⁺]_i) in CXCR3A-transfected CHO cells. Results are displayed as mean (± SEM) increase of [Ca²⁺]_i of 4 independent experiments. Responses induced by 3 nM CXCL10_(1–77) and 270 nM CXCL10_(1–73) were compared using an unpaired t-test ($$ p ≤ 0.01). B Time between administration of the stimulus and response in sec (s). Results are displayed as mean (± SEM) of 3 independent experiments. Statistically significant differences between CXCL10_(1–77) and CXCL10_(1–73) were determined by an unpaired t-test ($$$$ p ≤ 0.0001). C and  D Representative curves show desensitization of CXCR3A-mediated [Ca²⁺]_i mobilization upon stimulation with 3 nM CXCL10_(1–77) following treatment with CXCL10_(1–73) or buffer as first stimulus. E Relative surface expression of CXCR3 on primary T lymphocytes activated with PHA and IL-2 (compared to medium-treated control cells) following stimulation with CXCL10_(1–77) and CXCL10_(1–73). Results are shown as median (± SEM) of 3 independent experiments with 9 different cell preparations in total. Responses induced by 30 nM CXCL10_(1–77) and 45 nM CXCL10_(1–73) were compared using an unpaired t-test ($$ p ≤ 0.01). F, G Levels of ERK1/2 and Akt phosphorylation in CXCR3A-transfected CHO cells stimulated with CXCL10 proteoforms. Results are shown as median (± IQR) of 4 to 8 independent experiments. Statistically significant ERK1/2 and Akt phosphorylation induced by CXCL10_(1–77) and CXCL10_(1–73) compared to medium-treated cells were determined by Mann–Whitney U test (* p ≤ 0.05, **, p ≤ 0.01, *** p ≤ 0.001). Comparison of the ERK1/2 and Akt phosphorylation induced by 10 nM CXCL10_(1–77) and 270 nM CXCL10_(1–73) was also performed through a Mann–Whitney U test ($ p ≤ 0.05, $$, p ≤ 0.01). H CXCR3 expression on PHA- and IL-2-stimulated T lymphocytes (gated as CD3⁺ CD56⁻ CD19⁻ cells) was evaluated through flow cytometry with proportions of CXCR3⁺ T lymphocytes and I MFI of CXCR3. J Chemotactic index (CI) showing migration of PHA- and IL-2-stimulated T lymphocytes after treatment with medium (HBSS + 0.1% BSA) as control condition (CO) or serial dilution of CXCL10_(1–77) (100 nM to 1 nM) or CXCL10_(1–73) (100 nM to 1 nM). Results are shown as median (± IQR) of 4 independent experiments with 10 different cell preparations in total. Statistically significant CI compared to medium-treated cells (* p ≤ 0.05, **, p ≤ 0.01, *** p ≤ 0.001, **** p ≤ 0.0001) or between CXCL10 proteoforms ($ p ≤ 0.05, $$ p ≤ 0.01) were determined by Mann–Whitney U test