KIR2DL1 and infection: Chicken fibroblast (DF-1) cells and human bronchial epithelial (Calu-3) cells were infected with recombinant CL69 (H5N1-wt), CL42 (H9N2-wt), or one of the reassortants: DF-1 cells were infected at a multiplicity of infection (MOI) of 0.003, and Calu-3 cells were infected at an MOI of 0.03.