CD86, also known as B7-2, is a 70 kDa glycoprotein and a type I membrane protein that belongs to the immunoglobulin superfamily. It is primarily expressed on antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells. CD86 serves as a ligand for two T cell surface proteins: CD28 and CTLA-4. The interaction between CD86 and CD28 provides a crucial co-stimulatory signal for T cell activation and survival, while binding to CTLA-4 negatively regulates T cell activation, thereby dampening the immune response. Additionally, CD86 plays a role in B cell function regulation and can influence IgG1 production. It is rapidly upregulated on B cells upon activation and can be induced on monocytes by interferon-gamma. CD86 is also involved in various immune processes, including the activation of the NF-kappa-B signaling pathway and the regulation of cytokine production.