Suppression of mitogen-induced and antigen - specific lymphocyte proliferation by Tci - L4 - ES. To determine the effects of Tci-L4-ES on mitogen-induced proliferation, PBMC from helminth-naïve lambs were cultured with Con A in the presence or absence of Tci-L4-ES (ES) or heat-inactivated Tci-L4-ES (HiES). To determine the effects of Tci-L4-ES on antigen-specific proliferation, PBMC from ovalbumin (OVA)-immunized lambs were cultured with OVA in the presence or absence of ES or HiES. Proliferation assessed by incorporation of [3H] thymidine and expressed as counts per minute (cpm). (A) Proliferation of helminth-naïve PBMC at 72 h following culture with PBS alone (PBS), 5 μg/mL Con A (ConA + PBS), 5 μg/mL Con A + 30 μg/mL ES (ConA + ES) or 5 μg/mL Con A + 30 μg/mL HiES (ConA + HiES). (B) PBMC proliferation at 72 h following culture with 5 μg/mL Con A + 0, 3.75, 7.5, 15 and 30 μg/mL ES. (C-D) Caspase activity in PBMC cell lysates and Annexin V/7AAD staining in PBMC following 72 h culture with PBS, Con A, Con A + ES or Con A + HiES. (E) Proliferation of PBMC from ovalbumin-immunized lambs at 120 h following culture with PBS alone (PBS), 5 μg/mL Con A (ConA + PBS), 5 μg/mL Con A + 30 μg/mL ES (ConA + ES), 10 μg/mL OVA (OVA), 10 μg/mL OVA + 30 μg/mL ES (OVA + ES) or 10 μg/mL OVA + 30 μg/mL HiES (OVA + HiES). Data represents mean ± SEM from three replicate cultures from three helminth-free lambs. *P < 0.05, **P < 0.01, ***P < 0.001 (one way ANOVA followed by the Tukey post hoc test for pairwise comparison of means). In panel (B) only significant differences between ES-treated and non-ES treated cultures are indicated.