Immune cell subset differentiation and tissue inflammation

Table 1 Characterization of lymphoid cell subsets

Subsets		Markers	Frequency	Cytokines	Functions
TC	Th1	IL-2⁺TNF-β⁺IFN-Ɣ⁺	20% in blood CD4+ TC	IL-2, IL-12IFN-γ, TNF-α	↑MØ↑Cell-mediated immunity
	Th2	IL-4⁺IL-5⁺IL-10⁺IL-13⁺	2% in blood CD4+ TC	IL-4, IL-5, IL-10 IL-25, IL-13	↑Ab, Eos↓MØ function
	Th17	IL-17⁺RORγt⁺	0.5% in blood CD4+ TC	IL-21, IL-22, IL-24IL-26, IL-17A, IL-17F	Defend host↑Autoimmune disease
	Treg	Foxp3⁺IL-10⁺	5% in PBMC	IL-10, TGF-β	↓Autoimmune disease
	Tfh	CXCR5⁺	13.5%in blood CD4+ TC	IL-21	↑BC activation and functional differentiation
	Th22	AHR⁺CCR4⁺CCR6⁺CCR10⁺	0.05%In blood CD4+ TC	IL-17, IL-22	↓Immune activation
BC	Fo B2	CD21/35^intCD23⁺CD24^lowCD62L⁺CD93-IgM^lowIgD^high	4.3% in blood CD19+ BC	IgD, IgM	↑Adaptive response
BC	MZ B2/B1-like	CD21/35^highCD23-CD24⁺CD93⁻IgM^highIgD^low	17% in blood BC	IgM	Respond toblood-borne pathogen

CD4+ helper T cells (TC) can be subdivided into seven groups, which include T helper cells Th1, Th2, Th17, regulatory T cells (Treg), Th9, T follicular helper cells (Tfh), and Th22. Th1 drive autoimmune diseases, while Th2 synthesize interleukin (IL)-4, IL-5, IL-6, and IL-1, and facilitate antibody production. Th17 produce IL-17 and play critical roles in autoimmunity and inflammatory diseases. Treg are in charge of suppressing potentially deleterious activities of Th cells. Th9 protect hosts against helminthic infection and also mediate allergic disease. Tfh are known to regulate BC activation and functional differentiation. Th22-secrected IL-22 maintains intestinal epithelial barrier integrity and stimulates the secretion of antimicrobial peptides that limit bacterial dissemination and intestinal inflammation. Bone marrow (BM)-derived B cells (BC) develop into either follicular (Fo) BC or marginal zone (MZ) BC in the spleen. Fo BC participate in TC-dependent immune responses to protein antigens. MZ BC express high levels of CD21 and CD1d, and respond vigorously to blood borne pathogens. Both B-1a and B-1b BC seed the peritoneal and pleural cavities. While B-1a BC contribute to innate-like immune responses, B-1b BC contribute to adaptive immunity

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