Macrobiota - helminths as active participants and partners of the microbiota in host intestinal homeostasis

Homeostatic interactions between helminths, commensals and the host immune system; red arrows denote pro-inflammatory pathways, blue arrow counter-inflammatory. Direct tissue damage provokes release of alarmins (IL-33, also TSLP and IL-25) and can allow bacterial translocation with consequent TLR stimulation of host cells. Helminth secreted products (ES) are known to inhibit expression of the IL-33R (ST2) and host responses to TLR ligation. In addition, both helminths and commensals maintain host immunoregulatory networks through ES products and the production of short chain fatty acids (SCFAs).167