Functional antibodies are indispensable tools for research through their capacity to affect cell processes in vitro and in vivo, and they typically fall into one of these categories: activation, neutralization, blocking, and depletion. Functional antibodies can be leveraged to ask specific questions on cell signalling pathways, making it possible to elucidate effector functions of such signalling pathways. In this blog, we discuss how functional antibodies can be experimentally applied, with focus on activation, blocking, and neutralizing examples.

 

Activating antibodies can be used to induce a cell from a resting to an active state. For example, the expression of surface marker CD44 increases as B cells become activated or progress to the memory phenotype, making CD44 a valuable marker for memory cell subsets. Our Ultra-LEAF™ Purified anti-mouse CD44 Antibody activates CD44 on murine B cells and induces B cell spreading on anti-mouse CD44 coated surfaces.

 

 

Neutralizing antibodies bind a soluble factor and neutralize or negate its downstream cell effect, such as cell differentiation or cell proliferation. For example, granulocyte/macrophage-colony stimulating factor (GM-CSF), is a growth and development factor that promotes the proliferation and differentiation of hematopoietic progenitor cells, leading to the generation of macrophages. Ultra-LEAF™ Purified anti-human GM-CSF Antibody is designed to neutralize the proliferation of cells induced by GM-CSF, enabling investigation of effector functions of macrophages.

 

 

Blocking antibodies bind a cell surface target to block or interfere with a biological response. For example, TIGIT is an immunosuppressive receptor expressed by NK and T cells and an emerging immune checkpoint due to its property of mediating exhaustion of NK cells in tumors. Ultra-LEAF™ Purified anti-mouse TIGIT (Vstm3) Antibody blocks binding between TIGIT and ligand CD155, giving researchers insight into downstream NK cell functions and NK cell-associated TIGIT signaling pathways used by tumors to evade immune responses.

 

 

In summary, scientists rely on functional antibodies for an array of research purposes: to bind to and inhibit the function of a protein so as to mitigate its effector functions on cells at the molecular level, or to bind to cell surface receptors so as to investigate the functionality of receptors and specific cell signal pathways.Through their capacity to mimic or disrupt cell functions in vitro or in vivo, functional antibodies are powerful tools aiding manipulation of biological functions enabling scientists to query specific questions.