TIM-3 (T-cell immunoglobulin and mucin domains-containing protein 3), also known as hepatitis A virus cellular receptor 2 (HAVCR2), is a member of T-cell immunoglobulin and mucin family. It is specifically expressed on the surface of Th1 cells, and its ligand Galectin-9 is highly expressed in the tumor microenvironment. TIM-3 inhibits Th1 cell activity by binding to Galectin-9. Therefore, anti-TIM-3 antibodies can prevent its negative regulation on the immune system and may be used for tumor treatments.
mRNA expression verification:
Fig 1. Molecular identification of the B-hTIM-3 humanized mice. Mouse TIM-3 mRNA was detected in both the wild type and the B-hTIM-3 heterozygous mice, while human TIM-3 mRNA was detected only in the B-hTIM-3 heterozygous mice.
Protein expression verification:
Fig 2. Spleen cells from both wild type (WT) C57BL/6 and the B-hCD27 homozygous mice were analyzed by flow cytometry. Mouse TIM-3+ cells were detected in non-T and non-B cells from the WT mice, while human TIM-3+ cells were detected in non-T and non-B cells from the B-hTIM-3 homozygous mice.
Fig 3. Spleen cells from both wild type (WT) C57BL/6 and the B-hTIM-3 homozygous mice were analyzed by flow cytometry. Mouse TIM-3+ T cells were detected in the WT mice, while human TIM-3+ T cells were detected in the B-hTIM-3 homozygous mice.
TIM-3 antibody efficacy validation:
Fig 4. B-hTIM-3 mice were used for hTIM-3 antibody efficacy validation. Mouse colon cancer MC38 cells were subcutaneously transplanted into B-hTIM-3 homozygous mice, and animal were grouped into control to treatment groups (n=5) when the tumor size is approximately 100 mm3. Anti-hTIM-3 antibody shows substantially inhibitory effects. The average ± SEM of tumor sizes are shown in the figure. B-hTIM-3 mice are effective tools for hTIM-3 antibody efficacy validation.