Butyrophilin subfamily 3 member A2 (BTN3A2 (also known as CD277 isoform A2 in the BTN3 family context))

Molecular Classification

Receptor-like immunoglobulin superfamily protein, Immune checkpoint/immune modulatory molecule (B7-like family), Other (cell-surface glycoprotein)

Other Names

BTN3A2, Butyrophilin-like protein 2, BT3.2, CD277 (BTN3 family designation), Butyrophilin, subfamily 3, member A2

Disease Roles

Cancer (modulates intratumoral immune cell infiltration; BTN3 family studied in tumor immunity)Infection (BTN3 family involved in γδ T-cell responses to infection; BTN3A1 is necessary, BTN3A2 structurally related and part of the complex)

Butyrophilin subfamily 3 member A2 Overview

Butyrophilin subfamily 3 member A2 (BTN3A2) is a cell-surface glycoprotein of the immunoglobulin superfamily located at the plasma membrane, with two extracellular Ig domains and lacking the intracellular B30.2 domain that is present in BTN3A1; it modulates T-cell responses in adaptive immunity and can inhibit IFN-γ release from activated T cells. BTN3A family members share high structural homology with the B7 superfamily and form V-shaped ectodomain homodimers; antibodies binding the BTN3 ectodomain can modulate Vγ9Vδ2 T-cell activation, highlighting the family’s role in immune regulation relevant to infection and tumor immunity.

Mechanism of Action

Antibody binding to BTN3A ectodomain modulates γδ T-cell activation (agonist 20.1 mimics phosphoantigen-mediated activation; antagonist 103.2 inhibits), demonstrating immune-modulatory mechanism via BTN3 family surfaces

Biological Functions

Immune response modulation

Regulation of T-cell responses in adaptive immunity

Inhibition of interferon-gamma (IFN-γ) release from activated T cells

Forms extracellular V-shaped homodimers via C-type Ig domain

Disease Associations

Cancer (modulates intratumoral immune cell infiltration; BTN3 family studied in tumor immunity)

Infection (BTN3 family involved in γδ T-cell responses to infection; BTN3A1 is necessary, BTN3A2 structurally related and part of the complex)

Safety Considerations

Class-related concern: immune modulation may risk immune-related adverse effects (e.g., off-tumor T-cell activation or suppression) inferred from immune checkpoint targeting generally; direct BTN3A2-specific clinical safety data are limited in cited sources

Interacting Drugs

No approved small-molecule drugs specifically targeting BTN3A2 identified in public references; BTN3 family-targeting antibodies (e.g., experimental agonist 20.1 and antagonist 103.2) bind BTN3 ectodomains in structural/functional studies

Associated Biomarkers

Biomarker
BTN3A2 expression as a potential biomarker of immune modulation in tumors (epithelial expression associated with intratumoral immune infiltration in BTN3/BT3.2 studies)