Secretory calcium-dependent phospholipase A2 that primarily targets extracellular lipids, exerting anti-inflammatory and immunosuppressive functions. Hydrolyzes the ester bond of the fatty acyl group attached at sn-2 position of phospholipids (phospholipase A2 activity) with preference for phosphatidylethanolamines and phosphatidylglycerols over phosphatidylcholines. In draining lymph nodes, selectively hydrolyzes diacyl and alkenyl forms of phosphatidylethanolamines, releasing omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoate and docosahexaenoate that are precursors of the anti-inflammatory lipid mediators, resolvins. During the resolution phase of acute inflammation drives docosahexaenoate-derived resolvin D1 synthesis, which suppresses dendritic cell activation and T-helper 1 immune response. May act in an autocrine and paracrine manner. Via a mechanism independent of its catalytic activity, promotes differentiation of regulatory T cells (Tregs) and participates in the maintenance of immune tolerance. May contribute to lipid remodeling of cellular membranes and generation of lipid mediators involved in pathogen clearance. Displays bactericidal activity against Gram-positive bacteria by directly hydrolyzing phospholipids of the bacterial membrane.
