Therefore, blood-derived PMNs and bone marrow-derived macrophages (BMMs) were isolated from myeloid KLF4 knockout (mKLF4 KO) and KLF4 wildtype (mKLF4 WT) mice and stimulated for 6 hours with capsule-deficient R6x pneumococci (multiplicity of infection (MOI) 1). The gene discussed is KLF4; the disease is infection.