Human TIGIT and CD155 Inhibitor Screening ELISA Kit

Catalog Number:

V48D30

Background:

Human CD155 expressed on antigen‐presenting cells or tumor cells binds to ITIM domains (TIGIT) to down‐regulate T cell and natural killer (NK) cell functions. When TIGIT binds to CD155 on cells, it acts as an immune checkpoint that shuts down T cells and natural killer (NK) cells, helping tumors hide from the immune system. The development of anti-tumor molecules such as antibody or small molecule medicine to block this interaction may wake the immune system back up to fight cancer.

Applications:

This kit is developed to screen the tested molecules, such as antibodies or other molecules, against TIGIT that block the interaction between TIGIT and CD155. The assay detects any molecules or antibodies in serum/plasma or purified antibody (monoclonal & polyclonal) that inhibit TIGIT binding to its receptor CD155 in vitro. The test is both species and isotype independent. It is for research use only.

Description:

This kit was validated by a known monoclonal antibody – Vibostolimab. The binding between TIGIT and CD155 is blocked by this antibody in a dose-dependent manner, see figure.

Biosafety Level:

BSL-1

Assay Principles:

This kit is developed for a blocking ELISA format with a 96-well plate pre-coated with TIGIT protein. The whole process should take about 2.5 hours. The samples or provided positive/negative controls will be added to bind to TIGIT. The positive control will be captured on the plate by TIGIT, while the negative control will remain in the supernatant and get removed during washing.  A labeled CD155 (provided) will be added to the plate. After detecting and reading at 450 nm, the positive control wells generate a lower reading as it blocks the binding between TIGIT and CD155 while negative control wells generate a higher reading. The absorbance of the sample is inversely dependent on the titer of the antibodies or molecules blocking this interaction between TIGIT and CD155.

The kit consists of 96-well detachable plate with TIGIT pre-coated, Positive control, Negative control, labeled CD155, TMB and dilution/wash/stop buffer.

Brief protocol (detailed protocol is provided with the product):

1. Detach wells from plate based on your samples and keep at room temperature. Dilute your samples, positive and negative controls in sample dilution buffer and add them to wells (0.1 ml/well). Incubate at 37°C for 1 hour or room temperature for 1.5 hour. Wash wells 4 times by wash solution (0.3 ml/well).
2. Add labeled CD155 (100 µl/well). Incubate at room temperature for 1 hour. Wash wells as mentioned.
3. Add TMB to each well (100 µl /well) and incubate at room temperature for 10-30 minutes.
4. Stop the substrate reaction by adding stop solution (100 µl /well). Absorbance (OD) is calculated as the absorbance at 450 nm. The OD Value inversely reflects the amount of antibodies or molecules blocking this interaction between TIGIT and CD155.

Storage and shipping condition:

Shipment with room temperature. The unopened kit is stable for 6 months from the date of manufacture when stored at 2°C to 8°C. Avoid light. The shelf life is 60 days from the date of opening.