Pharmacology · Class
Other immunomodulating biologics !
Biologics that act on lymphocytes rather than on a cytokine: they block T-cell co-stimulation, the IL-2 receptor or a B-cell survival factor.
Updated 2026-11-01
What they are
Abatacept blocks the second signal that T cells need to switch on (rheumatoid and psoriatic arthritis, prevention of graft-versus-host disease); basiliximab blocks the IL-2 receptor on activated T cells to prevent early kidney-transplant rejection; belimumab neutralises BLyS (BAFF), a survival factor for B cells, in systemic lupus erythematosus and lupus nephritis.
Mechanism of action
A T cell needs two signals: the antigen presented on MHC (signal 1) and co-stimulation from CD80/CD86 on the antigen-presenting cell binding CD28 (signal 2). It then makes IL-2 and multiplies through the high-affinity IL-2 receptor, whose alpha chain is CD25. B cells depend on BLyS to survive and mature into antibody-producing cells. Each drug interrupts one of these steps.
Target: T-cell co-stimulation (CD80/CD86), IL-2 receptor alpha (CD25) and the B-cell survival factor BLyS (BAFF)
Drugs in this class
- AbataceptA fusion protein that blocks the second signal T cells need to switch on. Used in rheumatoid and psoriatic arthritis…CD80 and CD86 (B7-1 and B7-2) on antigen-presenting cells
- BasiliximabAn antibody against the IL-2 receptor (CD25), given intravenously around kidney transplant surgery to prevent early…IL-2 receptor alpha chain (CD25)
- BelimumabA human antibody against BLyS (BAFF), a B-cell survival factor, for systemic lupus erythematosus and lupus nephritis.B-lymphocyte stimulator (BLyS, also called BAFF)
Others in the class
- belatacept
- rituximab (anti-CD20)
Test yourself
Think of the answer, then tap the question to see it.
What are the two signals a naive T cell needs to become activated?
Antigen on MHC binding the T-cell receptor, and co-stimulation from CD80/CD86 binding CD28.
Which molecule does basiliximab bind?
CD25, the alpha chain of the high-affinity IL-2 receptor on activated T cells.
Which autoimmune disease is treated with belimumab?
Systemic lupus erythematosus, including lupus nephritis.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 39 (McGraw Hill, 2023); Abatacept Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); Belimumab Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026).
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Representative model, for educational purposes only.