Calcarea carbonica potentiates T cell-mediated cancer cell killing in vitro . (A) Percent apoptosis of EAC cells co-cultured with T cells at multiple effector to target ratios (5:1, 10:1 and 50:1), isolated from untreated or placebo-/calcarea carbonica-treated tumor-bearing mice. Further for all co-culture experiments effector to target ratio was kept as 10:1. (B) Graphical representation of sub-G0/G1 populations and Annexin-V-positive populations amongst EAC and p53-silenced EACs co-cultured with or murine T cells from untreated or placebo-/calcarea carbonica-treated tumor-bearing mice. Similarly human breast cancer cell lines, MCF-7/HBL-100/MDA-MB-231 cells were co-cultured with human T cells for 48 h to determine tumor cell apoptosis. Prior to co-culture, these human T cells were primed with placebo-/calcarea carbonica-treated tumor supernatant for 72 h. The transfection efficacy of p53-shRNA was determined by Western blot (inset). (C) MCF-7 cell apoptosis when co-incubated with placebo-/calcarea carbonica-primed human T cells (contact-dependent) or with supernatants of placebo-/calcarea carbonica primed T cells (contact-independent) was determined flow cytometrically. (D) Percent apoptosis of MCF-7/HBL-100 cells when co-cultured with placebo-/calcarea carbonica-primed CD4+ and/or CD8+ T cells. Values are mean ±SEM of five independent experiments. *p < 0.05 and **p < 0.001 when compared with respective tumor-bearing control/drug-treated sets and placebo-treated/drug-treated sets.