Table 1:
Reporter systems to track different immune cells and their functions by single cell imaging*
| Cell Type/Other | Reporter | Notes | Examples |
|---|---|---|---|
| T Cells | GFP, CFP, DsRed | Requires adoptive cell transfer | (29) |
| PA-GFP | Photoactivatable fluorescent reporter useful for cell tracking; requires adoptive cell transfer | (52) | |
| DPE-GFP | A pan T cell marker, can also label pDCs | (25) | |
| NFAT-GFP, NFAT-YFP;H2B-mCherry | Readout of TCR signaling | (44) | |
| IFN-γ-YFP | Subset of activated T cells; can also be produced by NK cells | (25) | |
| IL-10-GFP | Subset of T cells; can also be expressed by macrophages | (44) | |
| FOXP3-GFP, FOXP3-mRFP | Labels regulatory T cells; FOXP3 is on the X chromosome, be aware of X chromosome inactivation in females | (27) | |
| Nur77-GFP | Labels T cells and also B cells upon antigen receptor engagement | (111) | |
| GranzymeB-TdTomato | A a marker of granule exocytosis in cytolytic T cells and NK cells | (112) | |
| Tbx21-ZsGreen | For assessing Th1 responses in T cells | (113) | |
| CD2-eGFP | Labels peripheral T cells and some NK subsets | (114) | |
| IL-17F-CreeYFP | Many variants exist for studying Th17 cells in vivo | (115) | |
| IL-4-eGFP | Used to assess Th2 immunity | (116) | |
| IL-21-GFP | Used to study the role of TFH cells | (117) | |
| B Cells | GFP, CFP, DsRed | Requires adoptive cell transfer | (118) |
| PA-GFP | Photoactivatable fluorescent reporter useful for cell tracking; requires adoptive cell transfer | (52) | |
| CD19-tdRFP | Expressed by numerous B cells, adoptive transfer may be necessary if tissues are densely infiltrated by B cells | (50) | |
| Bcl6-YFP | A B cell marker already validated for 2-photon microscopy; also labels TFH cells | (119) | |
| Blimp-1-YFP | Expressed by B cells and highly expressed in plasma cells | (120) | |
| AID-GFP | Subset of B cells | (121) | |
| Dendritic Cells | CD11c(ITGAX)-YFP, CD11c-mCherry | Cells other than DCs can express CD11c | (122) |
| XCR1-Venus/+ | Homozygous mice are null for XCR1 | (56) | |
| XCR1-KIKGR/+ | Xcr1 replaced with photoconvertible fluorescent protein Kikume Green-Red (KikGR) | (56) | |
| CXCL9-RFP, CXCL10-BFP | These chemokines can also be expressed by other cell types, including monocytes, macrophages, granulocytes and non-immune cells | (32) | |
| SIGLEC-H-GFP | Expressed by pDCs | (55) | |
| Flt3-BFP2 | This construct has also been incorporated into a genetic model used to visualize DCs, macrophages, CD4+ and CD8+ T cells simultaneously (Flt3-BFP2, Mertk-GFP-DTR, Cd4-tdTomato, Cd8a-tdTomato) | (11) | |
| Zbtb46-GFP | A cDC marker that may be expressed in erythroid and endothelial populations | (123) | |
| Monocytes/Macrophages | CX3CR1-GFP/+ | This chemokine receptor can also be expressed by T cells, NK, DC, and macrophages. Homozygous mice are null for CX3CR1 | (124) |
| CCR2-RFP/+ | Homozygous mice are null for CCR2 | (62) | |
| CX3CR1-GFP/+;CCR2-RFP/+ | Homozygous mice are null for CX3CR1 and/or CCR2 | (62) | |
| Mertk-GFP-DTR | Homozygous mice are null for MerTK | (11) | |
| c-fms-GFP | c-fms is also known as Csf-1 receptor | (61) | |
| MacBlue | A gal4-responsive UAS-ECFP cassette also under the Csf-1 receptor promoter | (125) | |
| Dye-conjugated Ferumoxytol | Administered to mice several hours before imaging | (25) | |
| Dye-conjugated dextrans and dextran nanoparticles | Administered to mice several hours before imaging; can be used to label blood vessels in short-term after administration | (72) | |
| Dye-conjugated anti-CD169 mAb | Used to label SCS macrophages | (126) | |
| Dye-conjugated anti-F4/80 mAb | A pan macrophage marker in mice | (62) | |
| Neutrophils | Dye-conjugated anti-Ly-6G mAb | Imaging is performed shortly after administration (~15 min) | (127) |
| Dye-conjugated anti-Gr-1 mAb | Imaging is performed shortly after administration (~15 min) | (127) | |
| LysM-GFP | Can also be expressed by macrophages | (78) | |
| Dye-conjugated anti-neutrophil elastase mAb | Imaging is performed shortly after administration (~ 15 min) | (86) | |
| CXCL12-mRFP | Can also be expressed by stromal cells | (81) | |
| SYTOX Green | Used to visualize NETs (extracellular DNA labeling); also demarcates cell death | (86) | |
| Innate Lymphocytes | GFP, CFP, DsRed | Requires adoptive cell transfer | (93) |
| CXCR6-GFP | Can be used to track ILCs and iNKT cells but is also expressed by some T cells | (90) | |
| Megakaryocytes and Platelets | PF4-cre tdTomato | Labels megakaryocytes as well as platelets, which are defined based on their smaller size | (89) |
| Dye-conjugated anti-CD49b mAb | Labels all platelets | (86) | |
| CD41-YFPki/+ | Labels a fraction of platelets | (86) | |
| HSC-Derived Cells | GFP, CFP, DsRed | Requires adoptive cell transfer and is used to track HSCs and their progeny | (85) |
| Non-Immune Components | Dye-conjugated anti-Lyve-1 mAb | Labels lymphatics | (46) |
| AngioSPARK | Labels blood vessels | (72) | |
| Second Harmonic Generation (SHG) | Applicable to multiphoton (not confocal) microscopy; enables visualization of collagen fibers | (92) | |
| IL-7-eCFP | Expressed by stromal cells in thymus and bone marrow | (45) | |
| GCaMP6s | Sensor of calcium flux; relevant in the context of e.g. virus-infected cells | (40) | |
| qDots | Bright, highly tunable fluorophores surface-engineered to maximize circulation | (128) | |
| Isolectin | Used to label endothelial wall of blood vessels | (129) | |
| Hoechst33342 and CellTracker dyes | Indiscriminately labels cell nuclei or cytosol; often used for adoptive cell transfer | (42) |
*
This list serves as a general survey of intravital imaging labeling strategies across cell types, however numerous Cre strains can additionally be incorporated into useable reporter systems.