[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Other immunomodulating biologics](https://durgical.com/en/pharmacology/classes/other-immunomodulating-biologics/) › Abatacept [Pharmacology](https://durgical.com/en/pharmacology/) · [Other immunomodulating biologics](https://durgical.com/en/pharmacology/classes/other-immunomodulating-biologics/) # Abatacept A fusion protein that blocks the second signal T cells need to switch on. Used in rheumatoid and psoriatic arthritis and to prevent graft-versus-host disease. Updated 2026-11-01 - Class: [Other immunomodulating biologics](https://durgical.com/en/pharmacology/classes/other-immunomodulating-biologics/) - Target: CD80 and CD86 (B7-1 and B7-2) on antigen-presenting cells - ATC code: L04AA24 ◆**CD80 and CD86 (B7-1 and B7-2) on antigen-presenting cells**Abatacept ⓘ The figure shows human CTLA-4 bound to B7-1 (CD80); abatacept carries this same CTLA-4 binding domain, fused to an IgG1 Fc. **Target in 3D:** CD80 and CD86 (B7-1 and B7-2) on antigen-presenting cells. PDB structure 1I8L (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1I8L) · Drag to rotate · pinch to zoom ## Mechanism of action Abatacept is the extracellular domain of human CTLA-4 joined to a modified Fc portion of IgG1. CTLA-4 binds CD80 and CD86 more strongly than CD28 does, so abatacept occupies them and the CD28 co-stimulatory signal is lost. Without this second signal, naive T cells do not fully activate, make less IL-2 and drive less synovial inflammation. It does not deplete T cells. - CTLA-4-Ig binds CD80/CD86 - CD28 gets no co-stimulation - T cells do not fully activate - Less IL-2 and synovitis ## Pharmacokinetics **Absorption** Intravenous infusion or subcutaneous injection **Metabolism** Broken down like other proteins ## Indications - Rheumatoid arthritis [Rheumatoid arthritis →](https://durgical.com/en/conditions/rheumatoid-arthritis/) - Polyarticular juvenile idiopathic arthritis [Juvenile idiopathic arthritis →](https://durgical.com/en/conditions/juvenile-idiopathic-arthritis/) - Psoriatic arthritis [Psoriatic arthritis →](https://durgical.com/en/conditions/psoriatic-arthritis/) - Prevention of acute graft-versus-host disease, with a calcineurin inhibitor and methotrexate [Graft-versus-host disease →](https://durgical.com/en/conditions/graft-versus-host-disease/) ## Adverse effects ### Common - Headache, dizziness - Runny nose, nosebleed - Nausea, diarrhoea, stomach pain - Injection-site bruising, redness and itching ### Serious (rare, important) - Serious infections, including tuberculosis reactivation, hepatitis B and urinary infections - Worse breathing problems in people with chronic obstructive pulmonary disease - Severe allergic reactions - Lymphoma and skin cancer have been reported ## Contraindications - Hypersensitivity to abatacept - Active serious infection ## Key interactions **TNF inhibitors and anakinra** More serious infections without added benefit; not combined. **Vaccines, especially live vaccines** Not given during treatment or for three months after without the team's review. ## What is monitored - Latent tuberculosis test and hepatitis B history before starting - Signs of infection - Breathing in people with COPD ## Administration and safety - The intravenous form is a powder reconstituted with sterile water and infused by staff; the subcutaneous form is a prefilled syringe or autoinjector. - The laboratory is told about abatacept before blood tests. ## Nursing care - Before the first dose, confirm the latent tuberculosis test and ask about hepatitis B, COPD and recurrent infections. - Check that no TNF inhibitor or anakinra is being used. - Teach to report fever, cough, night sweats, burning on urination or a red, hot area of skin. - Review planned vaccines with the team. ## Pregnancy and breastfeeding Human data are limited; the treating team weighs benefits and risks. ## Memory aid abataCEPT = CTLA-4 reCEPTor decoy: it 'steals' CD80/86 so CD28 never gets signal 2. ## Test yourself Think of the answer, then tap the question to see it. ## Which T-cell signal does abatacept block? Signal 2, the co-stimulation from CD80/CD86 binding CD28. ## Which natural inhibitory receptor is abatacept built from? CTLA-4, whose extracellular domain is fused to an IgG1 Fc. ## Which lung disease calls for caution with abatacept? Chronic obstructive pulmonary disease, which can worsen. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/abatacept/) ## Related drugs - [Etanercept](https://durgical.com/en/pharmacology/etanercept/) - [Adalimumab](https://durgical.com/en/pharmacology/adalimumab/) - [Basiliximab](https://durgical.com/en/pharmacology/basiliximab/) ## Related conditions - [Rheumatoid arthritis](https://durgical.com/en/conditions/rheumatoid-arthritis/) - [Juvenile idiopathic arthritis](https://durgical.com/en/conditions/juvenile-idiopathic-arthritis/) - [Psoriatic arthritis](https://durgical.com/en/conditions/psoriatic-arthritis/) - [Graft-versus-host disease](https://durgical.com/en/conditions/graft-versus-host-disease/) [← Back to the class: Other immunomodulating biologics](https://durgical.com/en/pharmacology/classes/other-immunomodulating-biologics/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [Abatacept Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a606016.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [DailyMed - ADALIMUMAB- adalimumab-adaz injection, solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=3468792f-63ef-4916-8ed1-8214f327d9dd) (DailyMed (U.S. National Library of Medicine), 2025); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 39 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L04AA24) (WHO Collaborating Centre for Drug Statistics Methodology, 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/abatacept/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/abatacept/