To produce the recombinant human BTLA protein, a plasmid carrying the gene sequence for residues 31-157 of the human BTLA is expressed in mammalian cells. The target gene fragment is co-expressed with a C-terminal 10xHis-tag gene. SDS-PAGE confirms the BTLA protein purity exceeds 95%, and endotoxin content, measured using the LAL assay, remains below 1.0 EU/μg. ELISA testing validates the BTLA protein's functionality, with specific BTLA recombinant antibody(CSB-RA773799MAIHU) binding and an EC50 range of 11.56-13.00 ng/mL.
Human BTLA is an important co-inhibitory receptor that plays a significant role in regulating immune responses. BTLA is a member of the immunoglobulin superfamily and is primarily expressed on various immune cells, including T cells, B cells, NK cells, and dendritic cells (DCs) [1][2]. It negatively regulates immune activation, thereby maintaining immune homeostasis and preventing excessive immune responses that could lead to autoimmunity or tissue damage [1][3].
The binding of BTLA to the herpes virus entry mediator (HVEM) inhibits T cell and B cell activation, leading to reduced cytokine production and proliferation [4][5]. Specifically, BTLA engagement has been shown to decrease phosphorylation of key signaling molecules in T cells, such as CD3ζ, and in B cells, including Syk and PLCγ2, thereby dampening their activation [6][7]. This inhibitory signaling pathway is crucial for the regulation of immune responses, particularly in the context of chronic infections and cancer, where BTLA expression is often upregulated [8][9].
In the context of cancer, BTLA has been implicated in creating a protumor microenvironment by promoting immune evasion mechanisms [4][10]. Studies have demonstrated that high levels of BTLA expression correlate with poor outcomes in various cancers, including chronic lymphocytic leukemia and melanoma [10][11]. The blockade of BTLA signaling has been proposed as a potential therapeutic strategy to enhance anti-tumor immunity by reinvigorating T cell responses [8][12].
Moreover, BTLA is involved in the regulation of immune tolerance and the maintenance of homeostasis within the immune system. It plays a role in the differentiation of Tregs and the modulation of dendritic cell functions, which are essential for inducing tolerance to self-antigens and preventing autoimmune diseases [13][14]. The dual role of BTLA in promoting both immune suppression and tolerance highlights its complexity as an immune checkpoint molecule [15][16].
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