Tissue-resident mast cells (MCs) have important roles in
IgE-associated and -independent
allergic reactions. Although microenvironmental alterations in MC phenotypes affect the susceptibility to
allergy, understanding of the regulation of MC maturation is still incomplete. We previously reported that group III
secreted phospholipase A2 (sPLA2-III) released from immature MCs is functionally coupled with
lipocalin-type
prostaglandin D2 (
PGD2) synthase in neighboring fibroblasts to supply a microenvironmental pool of
PGD2, which in turn acts on the
PGD2 receptor DP1 on MCs to promote their proper maturation. In the present study, we reevaluated the role of sPLA2-III in MCs using a newly generated MC-specific Pla2g3-deficient mouse strain. Mice lacking sPLA2-III specifically in MCs, like those lacking the
enzyme in all tissues, had immature MCs and displayed reduced local and systemic anaphylactic responses. Furthermore, MC-specific Pla2g3-deficient mice, as well as MC-deficient KitW-sh mice reconstituted with MCs prepared from global Pla2g3-null mice, displayed a significant reduction in
irritant contact dermatitis (ICD) and an aggravation of
contact hypersensitivity (CHS). The increased CHS response by Pla2g3 deficiency depended at least partly on the reduced expression of hematopoietic
PGD2 synthase and thereby reduced production of
PGD2 due to immaturity of MCs. Overall, our present study has confirmed that MC-secreted sPLA2-III promotes MC maturation, thereby facilitating acute anaphylactic and ICD reactions and limiting delayed CHS response.