Fig 2. BCG vaccination does not enhance specific IFNγ production of NK cells in response to a second BCG stimulation.

Mice were immunized with BCG or phosphate-buffered saline (PBS), and 6 weeks later, NK cells were isolated from the spleens of these animals (n = 5 per group). The purified NK cells were cultured (1.5 × 10⁶ /mL) in the presence or absence of BCG (MOI = 1) at 37°C for 24 h, and then the culture supernatants were harvested. The production level of IFNγ was measured by ELISA. The data are presented as mean ± standard deviation, and p values < 0.05 were considered statistically significant. Similar results were obtained in three independent experiments. NS, not significant.