Cytokine secretion by CD1d-LPC⁺ T cells. (A) T-cell subsets were flow-sorted as indicated for CD1d-LPC⁺ and CD1d-LPC⁻ cell population and stimulated with PMA and ionomycin. The supernatant was harvested and analyzed for the presence of IL-13, IL-5, IL-8, IL-17, IFN-γ, and IL-4 by Luminex, IL-17 by ELISA. The data shown are for each donor (n = 8) for each cytokine. Significant P values: IL-13, .001; IL-5, .003; IL-8, .02; IFN-γ, .049. (B) Differential expression of IL-13 and IFN-γ by CD1d-LysoPC⁺ T cells after anti-CD3 stimulation: CD3⁺CD1d-LysoPC⁺ and CD3⁺CD1d-LPC⁻ were flow-sorted as indicated in panel A and stimulated by plate immobilized anti-CD3 antibodies or control. Secretion of IL-13 and IFN-γ was monitored by Luminex after 40 to 48 hours of culture. Data shown are means (± SD) of 4 experiments (*P < .05). (C) Decline in anti-CD3–stimulated IL-13 secretion in human PBMCs after the depletion of CD1d-LysoPC⁺ cells: cultured human PBMCs were either mock-depleted or depleted of CD1d-LysoPC⁺ cells by flow sorting. The cells were then stimulated with anti-CD3, and the production of IL-13 monitored by Luminex. Data shown are means (± SD) of 3 experiments (*P < .05). (D) Secretion of IL-13 in response to LysoPC stimulation. Cultured PBMCs were flow-sorted as indicated in panel A. CD1d-LysoPC⁺ and CD1d-LysoPC⁻ T cells were then stimulated with LysoPC pulsed CD1d-expressing cell line (or unpulsed cells, as well as CD1d⁻ control cells as a control) in serum-free media for 40 to 48 hours. Secretion of IL-13 was monitored by Luminex. Data shown are means (± SD) of 3 similar experiments (*P < .05).