A 3-year-old boy and other male relatives have a history of multiple recurrent infections, including Aspergillus, Staphylococcus, Nocardia, and Pseudomonas species. Physical examination shows generalized tender lymphadenopathy. Laboratory findings show normal numbers of morphologically normal circulating WBCs. This child's increased susceptibility to infection is most likely caused by a defect in which of the following steps of the inflammatory response?
Activation of macrophages by interferon-γ
Oxygen-dependent killing of bacteria by neutrophils
Firm adhesion between leukocytes and endothelial cells