Table 1.

List antigens for the γδ TCR

Name	Species	TCR V-usage	Affinity	Comments	Reference
MHC and MHC-like recognition
I-Eb, k, s	Mouse	Vγ1+/Vγ2 +	>240 µM (estimated)		22,48,119
H-2k, b, f, q, s	Mouse	Vγ2Vα11	N.D.		30
HLA-A24	Human	Vδ1+	N.D.	Allo-HLA recognition	31
HLA-B27-ci	Human	Vγ4Vδ1	N.D.	Allo-HLA recognition	32
HLA-A2	Human	Vδ1+	N.D.	Allo-HLA recognition	33
HLA-A∗24:2	Human	Vγ5Vδ1	N.D.	Allo-HLA recognition but peptide loading required for increased stability of MHC	23
HLA-A2/MART-1	Human	Vδ1+	2.9–71 µM	Response restricted to MHC-presented MART-1 peptide	34
CD1-d	Human/Mouse	Vδ1+/Vδ3+	16–33 µM	Affinity higher upon lipid-antigen presentation but binding also to non-presenting CD1-d	12,24,35–37,39,40
CD1-c	Human	Vδ1+	23–125 µM	Affinity higher upon lipid-antigen presentation but binding also to non-presenting CD1-c	38
Qa-1b/Glu50Tyr50	Mouse	N.D.	N.D.	Unclear, if antigen is presented or not	41,42
MR-1	Human	Vδ1+	2.7–30.6 µM	No specificity for presented antigens	43
EPCR	Human	Vγ4Vδ5	90 µM	Generation of blocking antibody to identify antigen	25
MICA	Human	Vδ1+	110–900 µM	High-affinity NKG2D-ligand	10,44–46
ULBP4	Human	Vγ9Vδ2	N.D., but direct interaction shown by ELISA	High-affinity NKG2D-ligand	13
T10/T22	Mouse	Diverse/clones G8 (Vγ4δ5) and KN6 (Vγ4δ10)	0.1 µM	Used for generation of γδ TCR-transgenic mice with defined specificity	47–50
Ig-like recognition
Annexin A2	Human	Vγ8Vδ3	3 µM	Generation of blocking antibody to identify antigen	53
EphA2	Human	Vγ9Vδ1	N.D.	γδ TCR activation only if EphA2 is bound to ephrins on γδ T cell	54
hMSH2	Human	Vδ2+	N.D.	High-affinity NKG2D-ligand	55
Histidyl tRNA synthetase	Human	Vγ3Vδ2	N.D.	Cell surface exposition not shown	56,57
HSV-gI	Mouse	Vγ2Vδ8	N.D.	Conformational epitope at N-terminus of HSV-gI	58
SEA	Human	Vγ9+ (cytotoxic response), Vγ9− (cytotoxic response and proliferation)	N.D.	Superantigen from Staphylococcus aureus	59
OXYS	Human	Vγ9Vδ2	N.D.	Superantigen from Bacillus Calmette-Guérin	60
DX2	Human	Vγ9Vδ2	N.D.	Superantigen from Mycobacterium tuberculosis	61
Phycoerythrin (PE)	Human, Mouse, Ruminants	Human: Vγ1Vδ1 Mouse: Vγ1+/Vγ4+ (Spleen), Vγ7+ (intestine)	2.69 µM (Mouse)	No physiological antigen, protein from red algae	62
Cy3	Mouse	Vγ1+/Vγ4+	78.2 nM	Hapten, no physiological antigen	63
4-hydroxy-3-nitrophenyl acetyl (NP)	Mouse	Vγ1+	660 nM	Hapten, no physiological antigen	63
Insulin peptide B:9–23	Mouse	Vγ1+ (without immunization), Vγ4+ (if immunized with peptide)	N.D.	Response idependent of APCs	64,65
HSP-60 peptide	Mouse	Vγ1+	N.D.	Peptides of mycobacterial and mammalian origin recognized	66–68
Peptide from Listeriolysin O	Human	N.D.	N.D.		69
Peptide from Tetanus toxin	Human	Vγ9Vδ2	N.D.	Presented by HLA-DRw53	70,71
Ig λ-chain	Human	N.D.	N.D.	Recognition if antigen is not on cell surface; presentation mechanism involved?	72,73
Polyanionic molecules	Mouse	Vγ1Vδ6.3	N.D.	Response independent of APCs	74
B7 family-like proteins and phosphoantigen recognition
BTN3A1	Human	Vγ9Vδ2	N.D.	Required for phosphoantigen response, binds phosphoantigen intracellularly, no direct interaction with γδ TCR shown to date	90,91,94
BTN2A1	Human	Vγ9Vδ2	40–50 µM	Required for phosphoantigen response, Interaction with Vγ9-chain via HV4 and CDR2	103,104
Skint-1	Mouse	Vγ5Vδ1 (DETC)	N.D.	Butyrophilin-like molecule required for homing of Vγ5Vδ1+ DETCs, direct interaction with γδ TCR not shown	106–108
BTNL3	Human	Vγ4+	SPR: 20.7 µM, ITC: 3.5 µM	Heterodimer with BTNL8, interaction via HV4 and CDR2 of γ-chain, required probably for tissue homing and homeostasis	113,114
Btnl6	Mouse	Vγ7+	N.D.	Heterodimer with Btnl6, mouse homologue of BTNL3, interaction via HV4 and CDR2 of γ-chain, required probably for tissue homing and homeostasis	113