Table 1. Proposed functional classification of NLRs.

Although four subgroups of NLRs exist based on domain structure groupings [116], a distinct grouping emerges based on functional studies of particular NLRs characterized to-date. All of these functions can influence the outcome of DC activation although many of these proposed effects require more work to confirm their true function specifically within the DC. It should be noted that although some NLR members fall into multiple categories in the table above, in general each NLR appears only once and therefore might be specialized to a particular function.

Activity	Triggers	NLRs	Outcomes	Proposed DC Effect	Ref
Transcriptional regulation	Cytokines	CIITA NLRC5	MHC Class I & II transcription	Antigen presentation	[73, 109]
TLR-like activity	PAMP recognition	NOD1 NOD2	Synergistic induction of inflammatory signaling cascade (NF-κB, MAPK)	Activation (Figure 1b)	[46, 49, 110]
Inflammasome nucleation	DAMP or PAMP sensing	NLRP1 NLRP2 NLRP3 NLRP6 NLRP7 NLRP12 NLRC4/N AIP2,5	IL-1β secretion IL-18 secretion Pyroposis	Enhanced T cell priming?	[14, 22, 62, 111–113]
Signaling modulator	?	NLRP2 NLRP4 NLRP6 NLRP12 NLRX1 NLRC3	Inhibit NF-κB pathways	Modification of TLR induced maturation	[55, 57, 60, 63, 66, 114, 115]
Signaling molecule?	?	NLRP10 NLRP12	Migration	Licensing (Figure 1b)	[90, 94, 95]