T-cell Immunoglobulin and Mucin-Domain-Containing Molecule-3 (TIM-3), encoded by the HAVCR2 gene and also known as CD366, is an immune checkpoint receptor belonging to the immunoglobulin superfamily. It is expressed predominantly on immune cells and plays an important role in the regulation of immune responses.

Originally identified through homology with molecules implicated in hepatitis A virus receptor studies, subsequent research has established that TIM-3 functions primarily as an immune regulatory receptor rather than a bona fide viral entry receptor in humans.

Biological significance of TIM-3 / HAVCR2

• TIM-3 is encoded by the HAVCR2 gene and is inducibly expressed on activated CD4⁺ and CD8⁺ T lymphocytes, natural killer (NK) cells, and subsets of myeloid cells under inflammatory conditions.
• It functions as an inhibitory immune checkpoint receptor involved in the regulation of immune activation, peripheral tolerance, and immune homeostasis.
• Engagement of TIM-3 with ligands such as galectin-9 has been shown to modulate T-cell effector function, including reduced cytokine production and impaired proliferative responses.
• TIM-3 is commonly associated with T-cell exhaustion phenotypes, particularly in chronic infection and cancer, often in conjunction with other inhibitory receptors such as PD-1.
• Additional ligands, including phosphatidylserine and CEACAM1, have been reported to contribute to TIM-3–mediated immune regulatory pathways, although their relative functional contributions may vary depending on biological context.

Relevance in hematopathology and tumor immunology

• TIM-3 expression has been investigated in the context of the tumor immune microenvironment, including hematologic malignancies such as lymphomas and leukemias.
• Its expression on tumor-infiltrating lymphocytes has been associated with immune dysfunction and features consistent with T-cell exhaustion.
• In research settings, TIM-3 immunohistochemical detection is used to support characterization of immune checkpoint landscapes and to study tumor–immune system interactions in tissue biopsies.
• Current evidence supports its role primarily as a translational and investigational biomarker, rather than a standalone routine diagnostic or classification marker in hematopathology.

Anti-TIM-3 (HAVCR2) CE/IVD antibodies for IHC – key characteristics

• Validated for use on formalin-fixed, paraffin-embedded (FFPE) tissue sections.
• Designed for specific detection of TIM-3 (CD366) protein expression in immunohistochemistry applications.
• Supports research and diagnostic laboratory workflows, particularly in studies of immune checkpoint biology and tumor microenvironment profiling.
• CE/IVD-labeled products (where applicable) are intended for use in accordance with relevant regulatory frameworks for in vitro diagnostic applications.