Anti-Mouse ICOSL (HK5.3) In Vivo Antibody - Low Endotoxin (ICH1229-100mg)

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This product is clone HK5.3, a rat IgG2a monoclonal antibody directed against mouse ICOSL (ICOS ligand, also known as B7-H2, B7h, B7RP-1, GL50, or CD275; UniProt Q9JHJ8). Raised in rat and validated for blocking, neutralization, flow cytometry, and in vivo applications, HK5.3 recognizes the surface ligand rather than the ICOS receptor, allowing investigators to interrupt the ICOS-ICOSL costimulatory axis from the antigen-presenting-cell side. The rat IgG2a backbone is a common format for in vivo mouse studies and pairs naturally with matched isotype controls. This preparation is manufactured to low-endotoxin specifications (research grade <1 EU/mg; ultra-low <0.5 EU/mg) so that residual lipopolysaccharide does not confound immune readouts during systemic dosing, and it is supplied in bulk milligram-to-gram quantities suitable for repeated-dose tumor, autoimmunity, infection, and vaccination cohorts. It is offered for research use only. Because researchers typically search by clone, note that HK5.3 is a widely referenced tool for functional ICOSL blockade in mouse models. ICOSL (ICOS ligand / B7-H2 / CD275) is a member of the B7 family of costimulatory molecules and the sole ligand for ICOS (Inducible T-cell COStimulator, CD278), a CD28-family receptor. ICOSL is expressed constitutively on B cells, dendritic cells, and macrophages, and can be induced on non-hematopoietic cells such as endothelial and epithelial cells by inflammatory cytokines. Engagement of ICOS by ICOSL delivers a costimulatory signal that promotes T-cell activation, survival, and effector cytokine production. The ICOS-ICOSL axis is particularly important for the differentiation and function of T follicular helper (Tfh) cells, germinal center formation, B-cell help, antibody class switching, and the generation of humoral responses. It also contributes to Th1, Th2, Th17, and regulatory T-cell biology. Because of these roles, the pathway is studied in autoimmunity, allergy, transplantation, infection, and antitumor immunity.