Proposed model of NADPHox activation by LTB₄. Either binding of IgG-coated targets with the FcγR or ligation of BLT1 by LTB₄ results in increased levels of intracellular Ca⁺⁺ and diacylglycerol (DAG). Ca⁺⁺ activates cPLA₂ activity, which results in enhanced AA release and subsequent generation of LTs. LTB₄ stimulates PKC-δ through an unknown mechanism, whereas DAG directly activates this enzyme. Once activated, PKC-δ induces phosphorylation and translocation of p47phox to the plasma membrane, generating ROIs. LTs may also act indirectly by increasing cPLA₂ activity (dashed line and question mark).