In Vitro Suppression/Stimulation Assay

Creative Biolabs has a highly experienced team of scientists who have a long history of successfully implementing complex in vitro suppression/stimulation assays. We offer accurate and effective solutions for in vitro suppression/stimulation assays to facilitate our clients' research and project development.

Checkpoint Proteins: Important Target for Immunotherapy

Tumor-specific T cells may be inactivated by immunosuppressive factors in the local tumor microenvironment, such as T-regulatory (Tregs) and myeloid-derived suppressor cells, or by co-inhibitory molecules that modulate T cell activation. In the tumor microenvironment, an increasing number of checkpoint proteins, including lymphocyte activations gene 3 (LAG-3), cytotoxic T lymphocyte antigen 4 (CTLA-4), programmed death (PD-1), and B and T lymphocyte attenuator (BTLA), have shown the ability to inhibit anti-tumor T cell responses. When tumor-specific T cells express these checkpoint proteins, they represent a significant barrier for the induction of effective anti-tumor immune responses. Restoring the capacity of T cells to recognize and eliminate tumors is the goal of immunotherapy. Blockade of these receptors has been shown to improve anti-tumor immune T cell responses. For instance, checkpoint blockade has been validated in humans with the approval of the anti-CTLA-4 antibody for metastatic melanoma.

Fig.1 Development of a spontaneous antitumor response and a T cell-inflamed tumor microenvironment. (Trujillo, 2018)

In Vitro Suppression/Stimulation Assay at Creative Biolabs

Studies have shown that in an in vitro suppression assay, CD4(+) CD25(high)LAG-3(+) T cells are endowed with potent suppressor activity, and their frequency is enhanced in the PBMCs of patients with cancer and is expanded at tumor sites. LAG3 expression is upregulated on tumor-infiltrating lymphocytes (TILs), and blockade of LAG3 can enhance anti-tumour T cell responses.

Blockade of negative regulators on T cells in the tumor microenvironment may improve anti-tumor T cell responses and lead to improved immunotherapeutic strategies for cancer. By leveraging the wealth of information on anti-tumor T cell responses, scientists at Creative Biolabs are experts in performing suppression/stimulation assay to help our clients research on the blockade of checkpoint proteins in the tumor microenvironment and are pleased to assist our clients based on their requirements.

• In suppression assays, Jurkat cells, Treg cells, or activated T cells could be used as suppressors and added into responder T cells in the presence or absence of anti-target checkpoint blocking antibody. Scientists at Creative Biolabs are proficient at the generation of Jurkat cells, Treg, or activated T cells. For the generation of activated T cells, naive CD4 T cells are stimulated by dendritic cells (DCs) and soluble anti-CD3 antibodies in proper concentration. Next, DCs are discarded, and activated T cells are collected. Then, T cell proliferation is measured.
• In stimulation assays, an important aspect of T cell stimulation is the rapid increase in cytoplasmic levels of calcium, which is released from intracellular stores and through the opening of the plasma membrane calcium release-activated channels. This release propagates the T cell activation signal, including the nuclear factor of activated T cell activation and cytoskeletal rearrangement.

The R&D scientific team at Creative Biolabs has designed and conducted many in vitro suppression/stimulation assays during the past few years. Many years of experience have led to a large number of successes. By applying our staff's knowledge and a proven quality system, Creative Biolabs continues to serve our clients with professionalism and expertise in the in vitro suppression/stimulation assays. For more detailed information, please feel free to contact us or directly send us an inquiry.

Reference

1. Trujillo, J. A.; et al. T cell-inflamed versus non-T cell-inflamed tumors: a conceptual framework for cancer immunotherapy drug development and combination therapy selection. Cancer immunology research. 2018, 6(9):990-1000.

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