TREM2 and infection: These signals can be activators (TLR 2, 4, 6; IL-1R, IFNγR, and TNFR), generally induced during conditions of poor nutrition, infections, use of antibiotics, pollution, smoking, or limitation of the microbiota; or suppressors (CD200R, SIRPα, mannose receptor, TREM2, IL-10R, and TGFβR) that are related to homeostasis and induced during conditions of balanced diet, minimal infections, limited antibiotic usage, or diverse microbiota (23).