DCs, Langerhas, some thymocytes, monocytes, activated Ts, epithelial cells

• Display of nonpeptide and glycolipid Ag for γδ and NKT cell responses

Thymocytes, Ts, NKTs

• Essential role in TCR signal transduction and in cell surface expression of the TCR

MHC II-restricted cells, some thymocytes, monocytes/mΦ, granulocytes

• co-receptor for MHC II-restricted T cell activation
• thymic differentiation marker for Ts
• receptor for HIV

Mature Ts, early thymocytes, B1as

• Marker of a B1 cells, which do not undergo somatic hypermutation,produce mainly IgM, and do not require T cell help

MHC I-restricted Ts, some thymocytes, subset of DCs

• co-receptor for MHC-I restricted Ts

B cell precursors, T cell precursors, bm stromal cells, neutrophils, monocytes, keratinocytes

• membrane-bound metallopeptidase responsible for cleaving a variety of inflammatory and vasoactive peptides

monocytes, mΦ, granulocytes, Bs, DCs, hepatocytes

• receptor for LPS, activating monocytes/ neutrophils to release cytokines (TNF) and up-reg adhesion molecules when LPS is bound
• binds peptidoglycan on gram⁺ bacteria, Hp60, ceraminds, modified lipoproteins, and anionic phospholipids
• soluble form reported to act as an acute phase protein and may regulate T cell activation and act as B cell mitogen

NKs, mΦ, mast cells, neutrophils, myeloid precursors, and the majority of early CD4⁺-CD8⁺- TCR fetal thymocytes

• subunit of low-affinity FcγR involved in phagocytosis of Ab-complexed Ag and in ADCC

FDCs, Bs (until plasma cells)

• part of B cell coreceptor w/ CD21 + CD81
• critical signal transduction molecule that regulates B cell development, activation, and differentiation

Bs

• ligation acivates tyrosine kinase-dependent pathways and may have a role in B cell proliferation and differentiation
• regulates B cell activation and proliferation via regulation of transmembrane Ca²⁺ channel subunit and cell-cycle progression

Bs, FDCs, subset of immature thymocytes

• receptor for C3d and iC3d (CR2)
• EBV receptor
• with CD19 and CD81, part of B cell coreceptor, a large signal transduction complex

Mature CD3⁺ thymocytes, most peripheral Ts, plasma cells

• Co-stimulation of T cell proliferation and cytokine production, upon binding CD80 or CD86

early lymphohematopoietic stem and progenitor cells, small-vessel endothelial clels, embryonic fibroblasts, some cells in fetal + adult nervous tissue

• cell-cell adhesion molecule
• also participates in inhibition of hematopoietic differentiation

erythrocytes, neutrophils, monocytes, eosinophils, Bs, and 10 - 15% of thymocytes

• CR1 - receptor for C4b/C3b - coated particales, mediating their adherence and phagocytosis
• facilitation of C3b and C4b cleavage, thus limiting complement activation

all mature B cell lineages except plasma cells, mΦ, FDCs, activated monocytes, endothelial cells, fibroblasts, DCs, keratinocytes, CD34⁺ hematopoietic cell progenitors

• binds to CD154 (CD40L)
• roles in B cell growth, differentiation, and isotype switching
• apoptosis rescue signal for germinal center Bs
• stimulation of cytokine production in mΦ and DCs
• up-red of adhesion molecules in DCs
• plays a critical role in the regulation of cell-mediated immunity as well as Ab-mediated immunity

all hematopoietic cells except RBCs

• tyrosine phosphatase that may remove Ps from signal transduction molecules involved  in T cell signalling, thus activating them
• regulates a variety of cellular processes, including cell growth, differntiation, mitotic cycle, and oncotic transformation
• essential role in T and B cell Ag-receptor mediated activation
• possible role in receptor-mediated activation in other leukocytes

PBLs

• MCP - binds the complement components C3b and C4b, allowing degradation by Factor I

Activated Bs and Ts, mΦ, low levels on resting peripheral blood monocytes and Dcs

• binds CD28 and CD152
• co-stimulator of T cell activation with CD86 when bound to CD28
• inhibits T cell activation when bound with CD152

DCs, memory Bs, germinal center Bs, monocytes

• B70 - major T cell costimulatory molecule, interacting with CD 28 (stimulatory) and CD152 (inhibitory)

activated Ts and Bs, monocytes, fibroblasts, neutrophils

• Fas - mediation of apoptosis-inducing signals

Activated Ts, perhaps some activated Bs

• negative regulator of T cell activation

Activated CD4⁺ Ts, small subset of CD8⁺ Ts and γδ Ts, activated basophils, platelets, monocytes, mast cells

• CD40L, inducer of B cell proliferation and activation, Ab class switching and germinal center formation
• costimulatory molecule and a regulator of T_H1 generation and fxn
• role in negative selection and peripheral tolerance

granulocytes, monocytes, NKs, subset of Ts and Bs, myeloid DCs

• CR3 - mediates phagocytosis of particles coated with iC3b or IgG

monocytes, mΦ, NKs, granulocytes, subset of Ts and Bs, DCs

• CR4
• similar to CR3

most hematopoietic and nonhematopoietic cell types

• binds to C8 and C9, may bind CD2
• inhibitor of MAC assembly

Bs, monocytes, mΦ, Langerhans, neutrophils, platelets

• FcγRll receptor for Fc portion of Ag-Ab-complexed IgG
• Major inhibitory role preventing the development of autoimmune disease
• Plays a major role in immune complex-induced tissue damage

• Igα and Igβ, required for signalling through BCR
• analogous to CD3

All leukocytes except most resting BS

• Plays an important role in cell signal trandsuction and mediation of the cytoskeleton
• Mutated in Wiskott-Aldrich syndrome