Furthermore, we successfully identified extracellular membrane vesicles (MVs) derived from the Lactobacillus-CFS, which recapitulated both the immune stimulatory and the IFN-γ dampening activity observed with the CFS alone, suggesting that gut bacteria-derived extracellular MVs are important modulators of human immunity with new implications for probiotic design. The gene discussed is IFNG; the disease is myalgic encephalomeyelitis/chronic fatigue syndrome.