Figure 7.

Lipopolysaccharide (LPS) treatment enhances interferon gamma (IFN-γ) production in maternal antibiotic treatment (MAT) effector CD8⁺ cells in vivo and in vitro. Control (CTRL) and MAT infant mice were infected at day of life (dol) 15 with vaccinia-ovalbumin (Vac-OVA, 1 × 10⁴ PFU intraperitoneal) and were treated with Escherichia coli-derived LPS (50 μg o.g.) every other day for 10 days (Vac-OVA + LPS). (A) At day of infection 11, lymphocytes were isolated from the spleens of CTRL and MAT mice infant mice and stimulated in vitro with SIINFEKL peptide, phorbol 12-myristate 13-acetate, and ionomycin for 5 h to analyze the percentage of IFN-γ- and TNF-α-producing CD8⁺ T effector cells (CD44⁺CD62L⁻, Teff) by flow cytometry (CTRL Vac-OVA, n = 3; CTRL Vac-OVA + LPS, n = 7; MAT Vac-OVA, n = 2; MAT Vac-OVA + LPS, n = 3). (B) Survival curve of CTRL and MAT infant mice following Vac-OVA infection and LPS treatment (CTRL Vac-OVA, n = 5; CTRL Vac-OVA + LPS, n = 5; MAT Vac-OVA, n = 2; MAT Vac-OVA + LPS, n = 11). Comparison of survival curves was performed by log-rank (Mantel–Cox) test. Data are representative of two infection experiments. (C) Pooled CD8⁺ T cells isolated from the spleens of uninfected dol 15 CTRL (n = 3) and MAT (n = 6) infant mice were stimulated with anti-CD3/anti-CD28 with or without Escherichia coli-derived LPS (1 μg/ml) for 72 h and analyzed for the percentage of IFN-γ and TNF-α-producing Teff cells by flow cytometry. Data are representative of three independent experiments.