Immune Checkpoints and the T cell

Immune Checkpoints and the T cell

Amanda Flies, Ph.D.

CTLA-4 prevents T cell activation by competitively inhibiting the co-stimulatory signal through CD28, as CD28’s ligands (B7-1 and B7-2) have a higher affinity/avidity for CTLA-4. CTLA-4 also transmits an inhibitory signal intracellularly, which reduces proliferation and cytokine production.


Immune checkpoints are stimulatory or inhibitory signals that play a major role in regulation of the immune system’s function. Interactions between surface molecules on immune cells lead to activation, differentiation and effector function, or inhibition of these activities. T cells, an important member of the adaptive branch of the immune system, are greatly affected by interactions between immune checkpoint molecules, including CD28 ↔ B7-1/B7-2 ↔ CTLA-4 interactions, PD-1 ↔ PD-L1/PD-L2, LAG-3 ↔ MHC, and TIM-3 ↔ galectin-9 interactions. Proliferation, clonal expansion, differentiation into T cell subsets, and effector functions all depend on stimulation or inhibition through these surface molecules. Thus, regulation of T cells by way of blocking or stimulating the immune checkpoints can have significant effects on the function of the immune system. Recent advances in immunotherapy targeting immune checkpoint molecules have demonstrated efficacy in modulating immune reactions to self-tissues in both cancer immunity and autoimmunity. Continued research into this growing field of study is critical for advancing immunotherapeutic treatments against human diseases using immune checkpoint molecules.

Immune Checkpoint Reagents Available from Cell Sciences:

CTLA-4 Fusion Proteins

Catalog No. Description
CRH030 Recombinant Human CTLA-4/CD152:Fc Chimera
CRH031 Recombinant Human CTLA-4/CD152:Fc Chimera Non-Lytic
CRH032 Recombinant Human CTLA-4/CD152:Mouse Fc Chimera
CRM035 Recombinant Mouse CTLA-4/CD152:Fc Chimera
CRM036 Recombinant Mouse CTLA-4/CD152:Fc Chimera Non-Lytic

PD-1 – PD-L1/2 Reagents

Catalog No. Description
CRH046 Recombinant Human PD-1/CD279:Fc Chimera
CRH047 Recombinant Human PD-1/CD279:Fc Chimera Non-Lytic
CRH036 Recombinant Human B7-H1/PD-L1/CD274:Fc Chimera
CRH037 Recombinant Human B7-H1/PD-L1/CD274:Fc Chimera Non-Lytic
CRH033 Recombinant Human PD-L2/CD273:Fc Chimera
CRH034 Recombinant Human PD-L2/CD273:Fc Chimera Non-Lytic
CRH035 Recombinant Human PD-L2/CD273:Mouse Fc Chimera
CRM044 Recombinant Mouse PD-1/CD279:Fc Chimera
CRM038 Recombinant Mouse B7-H1/PD-L1/CD274:Fc Chimera
CRM039 Recombinant Mouse B7-H1/PD-L1/CD274:Fc Chimera Non-Lytic
CRM037 Recombinant Mouse PD-L2/CD273:Fc Chimera

LAG-3 Reagents

Catalog No. Description
CMH003 Mouse Anti-Human LAG-3 Clone 17B4 Biotin mAb
CMH004 Mouse Anti-Human LAG-3 Clone 17B4 Blocking Azide Free mAb
CMH005 Mouse Anti-Human LAG-3 Clone 17B4 FITC mAb
CMH006 Mouse Anti-Human LAG-3 Clone 17B4 Blocking mAb
CMH007 Mouse Anti-Human LAG-3 Clone 11E3 Blocking mAb
CMH008 Mouse Anti-Human LAG-3 Clone 11E3 Blocking Azide Free mAb
CRH048 Recombinant Human LAG-3:Fc Chimera
CRM045 Recombinant Mouse LAG-3:Fc Chimera

TIM-3 Reagents

Catalog No. Description
CRH050 Recombinant Human Tim-3:Fc Chimera
CRH051 Recombinant Human Tim-3:Mouse Fc Chimera

Additional Immune Checkpoint Reagents

Catalog No. Description
CRH022 Recombinant Human Multimeric TNF-alpha
CRH023 Recombinant Human Multimeric FasL
CRH024 Recombinant Human Multimeric CD40L
CRH025 Recombinant Human Multimeric APRIL
CRH026 Recombinant Human Progranulin FLAG
CRH027 Recombinant Human Progranulin
CRH028 Recombinant Human B7-H4:Fc Chimera
CRH029 Recombinant Human B7-H4:Mouse Fc Chimera
CRH038 Recombinant Human B7-H2/CD275:Fc Chimera
CRH039 Recombinant Human B7-H2/CD275:Fc Chimera Non-Lytic
CRH040 Recombinant Human B7-H2/CD275:Mouse Fc  Chimera
CRH041 Recombinant Human B7-H3/CD276:Fc Chimera
CRH042 Recombinant Human B7-H3/CD276:Mouse Fc Chimera
CRH043 Recombinant Human ICOS/CD278:Fc Chimera
CRH044 Recombinant Human ICOS/CD278:Fc Chimera Non-Lytic
CRH045 Recombinant Human ICOS/CD278:Mouse Fc Chimera
CRH049 Recombinant Human Tim-1:Fc Chimera
CRH051 Recombinant Human Tim-3:Mouse Fc Chimera
CRH052 Recombinant Human Tim-4:Fc Chimera
CRM030 Recombinant Mouse Multimeric CD40L
CRM031 Recombinant Mouse Multimeric OX40L
CRM032 Recombinant Mouse Multimeric APRIL
CRM033 Recombinant Mouse Progranulin
CRM034 Recombinant Mouse B7-H4:Fc Chimera
CRM040 Recombinant Mouse B7-H2/CD275:Fc Chimera
CRM041 Recombinant Mouse B7-H2/CD275:Fc Chimera Non-Lytic
CRM042 Recombinant Mouse B7-H3/CD276:Fc Chimera
CRM043 Recombinant Mouse ICOS/CD278:Fc Chimera
CRM046 Recombinant Mouse Tim-4:Human Fc Chimera
CRM047 Recombinant Mouse CD137:Human Fc Chimera
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