Human Immune Cells

These videos show human immune cells that have been tagged with fluorescent markers to show them more clearly under the microscope.

Time-lapse video of a live human monocyte cell line (THP-1 cells) over 24 hours. These cells have been modified to express GFP (green fluorescent protein) in an inflammasome adaptor, ASC (Apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain). The immune response was activated by stimulating the cells with LPS, the main component of the outer membrane of gram-negative bacteria, and then with ATP. This process induced inflammasome activation, seen in the image when the GFP transitions from appearing dimly in the whole cell to brightly in the activated ASC molecules.

Immuno-fluorescent staining on fixed primary human monocytes that have been activated by exposure to LPS, the main component of the outer membrane of gram-negative bacteria, a major class of bacteria that includes some infectious types. In this image, the red fluorescence tracks IL-32, an inflammatory cytokine protein; green shows CD14, a protein produced mostly by macrophages, a type of immune cell; and blue is from a stain called DAPI that shows DNA. These cells were fixed before the image was taken, so this movie shows the cells from different angles at a single point in time.

This movie shows time-lapse imaging of human T cells purified from blood undergoing activation. A fluorescent dye (green) is loaded into cells to track the concentration of calcium ions inside the cell. When select surface proteins on the cells recognize and bind to their partners, they cause a quick burst of calcium (called a "flux") that ultimately changes gene expression of the cell. Small metal beads (black) were added to the T cells to provide an activation signal by mimicking the innate immune cells that would typically activate T cells in vivo. These beads are coated with antibodies that trigger two different surface proteins (CD3, CD28) on T cells that can drive activation and calcium signaling. The outlined cell has bound tightly to a bead and moves around with it, and at least 3 calcium fluxes can be seen. After these cells are activated, they proceed to divide and promote immune responses like the production of antibodies or the killing of infected or cancerous cells.