T Cell Activation and Expansion

T cells are a type of white blood cell called a lymphocyte which can actively ward off and destroy infected cells. As part of the immune response system, T cells relay signals to other immune cells that foreign particles are present. To fully understand the roles T cells play, immuno-oncology researchers have begun characterizing the different populations of immune cells, including T cells and their subsets.

T cell activation and expansion kits and reagents help isolate, activate, and expand your T cells while maintaining the viability of your isolated T cells for downstream immuno-oncology analysis.

Clonal T cell expansion is the process of T cell activation and proliferation which occurs naturally in vivo when the human body is actively fighting an infection or an immune system attack. In vitro, clonal T cell expansion happens when a naïve T cell recognizes and binds to a specific antigen, activating the T cell to proliferate rapidly—or expand (Figure 1).

Dynabeads T cell activation and expansion products mimic in vivo T cell activation from antigen-presenting cells (APCs). Key benefits of Dynabeads T cell activation and expansion kits include:

• Easy protocol—No need to prepare autologous APCs, feeder cells, antigens, or pre-coat antibodies to beads
• Physiological activation—Includes simultaneous signaling with agonistic monoclonal antibodies to CD3/TCR and CD28
• Stimulate and re-stimulate—Magnetic beads can be easily released from cells and re-added, enabling multiple rounds of cell re-stimulation.
• Viability and functionality—Cells keep their functionality with a cytokine profile and a full T cell repertoire reflecting in vivo settings

Dynabeads T-Activator CD3/CD28 products for human and mouse are ideal for short-time stimulation studies and T cell expansion of polyclonal T cells (e.g., T cell subsets isolated from whole blood, mononuclear cells, or tissue digests).

The CD3 and CD28 antibodies on the Dynabeads magnetic beads surface simultaneously bind the CD3 and CD28 antigens on the target cells, thus initiating the signaling pathway. CD28 signaling causes the initial activation of naive CD4 T cells by increasing the sensitivity of the T cell to antigen receptor engagement and, as a result, expansion is induced. 

The antibodies are coupled onto 4.5 µm-sized beads (almost as large as APCs), and the resulting 3D structure enables activation very similar to physiological activation in the body (Figure 2). The optimized antibody amount and product reproducibility results in consistently higher levels of activation compared to more primitive alternatives like mitogens or soluble antibodies.

The protocols are straightforward, highly consistent, and do not require additional factors such as autologous APC, mitogens, antigen, or feeder cells. Dynabeads T cell expansion kits outperform traditional home-brew methods for generic activation. Moreover, the same technology platform can be used when transitioning from mouse or human studies to clinical research.
 

Another application for Dynabeads T cell activation and expansion products is T cell re-stimulation and expansion of antigen-specific (Ag-specific) T cells from cell lines, cell clones, or freshly isolated and enriched Ag-specific T cells.

To allow for expansion of human antigen-specific T cells, the magnetic beads are conjugated with anti-CD3, anti-CD28, and anti-CD137 antibodies (Figure 3). CD137 (4-1BB) is a member of the tumor necrosis factor family, and agonistic anti-CD137 antibodies act as an activating co-stimulatory molecule especially important for effector/memory T cells and promote the survival and proliferation of T lymphocytes.

This technology allows you to activate and/or expand naïve and memory T cells, T cell clones, regulatory T cells, natural killer T (NKT) cells, and cytoxic T lymphocytes (CTLs) from mouse and human samples.