Cytotoxic T cells or CTLs (CD8+ T cells)

Cytotoxic T cells or CTLs (CD8+ T cells) are involved in the direct destruction of cells that have become cancerous or are infected by a pathogen. CTLs contain granules (sacs containing digestive enzymes or other chemical substances) that they utilize to cause the target cell to burst open in a process called apoptosis or tumor lysis. Our assays to evaluate CTL activity are:

  • T cell proliferation
  • T cell exhaustion
  • CD8+ T cell mediated tumor lysis
  • Antibody Dependent Cell Cytotoxicity (ADCC)
  • T cell migration assays

Helper T cells (CD4+ T cells)

Helper T cells (CD4+ T cells) lead to the production of antibodies by B cells and produce substances that activate CTLs and white blood cells known as macrophages. For example, CD4+ cells are targeted by HIV. HIV infects helper T cells and destroys them by triggering signals that result in T cell death. CD4 T cells recognize peptides bound to MHC class II molecules and are of two functional types: Th1 and Th2.

    • Th1 cells are specialized to activate macrophages that are infected by or have ingested pathogens. Th1 cells secrete IFNγ and TGFβ as well as other effector molecules and express membrane-bound CD40 ligand and/or Fas ligand. The expression of these molecules dictated their function. Th1 cells secrete IL-12 from dendritic cells and macrophages via IFNγ. Th1 cytokines are associated with with chronic inflammation, tissue injury and auto-immune disorders such as lupus.
    • Th2 cells are specialized for B cell activation and secrete the B cell growth factors IL-4 and IL-5. CD40 ligand is the membrane bound ligand of Th2 cells and binds to CD40 on B cells to induce B cell proliferation. Th2 cells also secrete proinflammatory cytokines IL-6, IL-10 and IL-13. Th2 are present in parasitic infections and allergic and asthma immune responses.
    • Th17 secrete cytokines IL-17 and is implicated in various diseases such as multiple sclerosis and other autoimmune diseases. Studies have shown the naïve CD4 T cells are differentiated into Th17 cells via cytokines IL-6, IL-21 and IL-23. Our assays to evaluate CD4+ cells are:
  • T cell proliferation
  • T cell exhaustion
  • CD4+ T cell mediated tumor lysis
  • Th1 cell differentiation
  • Th2 cell differentiation
  • Th17 cell differentiation
  • Th1/Th2/Th17 cytokine responses
  • Mixed Lymphocyte Reaction (MLR) 

Regulatory T cells (Tregs)

Regulatory T cells (Tregs) suppress the response of B cells and other T cells to antigens. Treg suppression regulates the immune response once it is no longer needed. Defects in regulatory T cells can lead to the development of an autoimmune disease. Our assays involving Treg cells are:

  • Treg suppression assays
  • Treg phenotyping
  • Treg migration assays

Natural Killer T cells (NKT cells)

Natural Killer T cells (NKT cells)have a similar name as a different type of lymphocyte called a natural killer cell. NKT cells are T cells and not natural killer cells. NKT cells have properties of both T cells and natural killer cells. Like all T cells, NKT cells have T-cell receptors. However, NKT cells also share several surface cell markers in common with natural killer cells. As such, NKT cells distinguish infected or cancerous cells from normal body cells and attack cells that do not contain molecular markers that identify them as body cells. We collaborate with Webbcures LLC in the development and execution of our NKT cell assays:

  • NKT cell proliferation
  • NKT cell exhaustion
  • NKT cell mediated tumor lysis
  • Antibody Dependent Cell Cytotoxicity (ADCC)
  • NKT cell migration assays

B cells

B cells are lymphocyte immune cells that produce specialized proteins called antibodies to counter pathogens. Antibodies identify pathogens by binding to them and targeting them for destruction by other immune cells. When an antigen is encountered by B cells that respond to the specific antigen, the B cells rapidly reproduce and develop into plasma cells and memory cells. The assays to evaluate B cells are:

  • B cell proliferation
  • B cell activation
  • B cell migration assays

Macrophages

Monocytes are white blood cells with a large, single nucleus and migrate from blood to tissue and develop into either macrophages and dendritic cells.

Macrophages are derived from monocytes. Monocytes exit blood vessels by passing through blood vessel endothelium to enter tissues. Once reaching their destination, monocytes develop into macrophages or into other immune cells called dendritic cells. Dendritic cells aid in the development of antigen immunity. Macrophages secrete cytokines to promote the development of certain macrophages that are needed for the role. Macrophages are present in nearly all tissues and actively remove dead and damaged cells, bacteria, cancerous cells, and cellular debris from the body. Macrophages also aid in cell mediated or adaptive immunity by capturing and presenting information about foreign antigens to immune cells. Macrophages are involved in other valuable functions in the body including hormone production, homeostasis, immune regulation, and wound healing. Macrophages have a key functional role across the body ranging from their role in the CNS as microglial cells to lung, reproductive, bone, skin and kidney functions.

Macrophages are classified as M1 macrophages also known as “killer” macrophages with pro-inflammatory cytokines and M2 macrophages are known as “repair” macrophages that produce anti-inflammatory cytokines. The assays that evaluate macrophages are:

  • Monocytes to M1 differentiation
  • Monocytes to M2 differentiation
  • M1/M2 class switching assay
  • Tumor Associated Macrophages (TAMs)
  • Mixed Lymphocyte Reaction (MLR)

Dendritic cells

Dendritic cells reside most often in the tissue of areas that meet external antigens. They are found in the skin, lungs, gastrointestinal tract, and inner layers of the nose. Dendritic cells function primarily to present antigenic information to lymphocytes in lymph nodes and lymph organs to aid in the development of antigen immunity.The assays that evaluate dendritic cells are:

  • Mixed Lymphocyte Reaction (MLR)
  • Dendritic cell migration assays