Mast Cell Subsets and Their Functional Modulation by the Acanthocheilonema viteae Product ES-62

Figure 6

Model of differential desensitisation of mast cell subsets by ES-62. Mucosal-type BMMC, CTMC, and PDMC exhibit differential functional responses to antigen (Ag)-mediated cross-linking of FcεRI and stimulation with LPS as summarised. The signalling mechanisms underlying the coupling to these differential responses and their desensitisation by ES-62 have not been fully delineated but our working model is that the FcεRI-mediated degranulation observed in PDMC involves PKCα and calcium mobilisation which are effectively targeted by ES-62. Although these cells express TLR4/MyD88, they are uncoupled from downstream functional LPS signalling by an as yet unknown mechanism. By contrast, mucosal-type BMMC exhibit both degranulation (via Ag/FcεRI) and cytokine (via FcεRI and LPS/TLR4) responses, requiring recruitment of additional signals such as PKCδ and MyD88 signalling which are both also targeted by ES-62.