[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › Other immunomodulating biologics

[Pharmacology](https://durgical.com/en/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)

## Key points

- Abatacept = CTLA-4 fused to an IgG1 Fc: it binds CD80/CD86 and blocks the CD28 second signal.
- Abatacept is not combined with TNF inhibitors: more serious infections.
- Basiliximab: anti-CD25 (IL-2 receptor alpha) induction at the time of kidney transplantation.
- Belimumab: anti-BLyS for lupus; watch for depression and suicidal thoughts and for infusion reactions.
- All: infections, latent TB where relevant, and no live vaccines without the team's review.

## Drugs in this class

- [**Abatacept** A 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](https://durgical.com/en/pharmacology/abatacept/)
- [**Basiliximab** An antibody against the IL-2 receptor (CD25), given intravenously around kidney transplant surgery to prevent early… IL-2 receptor alpha chain (CD25)](https://durgical.com/en/pharmacology/basiliximab/)
- [**Belimumab** A human antibody against BLyS (BAFF), a B-cell survival factor, for systemic lupus erythematosus and lupus nephritis. B-lymphocyte stimulator (BLyS, also called BAFF)](https://durgical.com/en/pharmacology/belimumab/)

## 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.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/classes/other-immunomodulating-biologics/)

[← All of pharmacology](https://durgical.com/en/pharmacology/)

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](https://medlineplus.gov/druginfo/meds/a606016.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [Belimumab Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a611027.html) (MedlinePlus (U.S. National Library of Medicine), 2026).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/pharmacology/classes/other-immunomodulating-biologics/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/other-immunomodulating-biologics/