Cytotoxic T-cells, or killer T-cells, are white blood cells that play an important role in our body’s immune response. They circulate in the blood, seeking out and attacking abnormal cells in the body, including bacteria, cancer cells, and cells infected by viruses or bacteria. Here, killer T-cells (colored blue) have attached themselves to HIV-infected cells (colored green) with actin molecules (yellow) that form a junction between the two cells. The killer T-cells produce proteins called perforin (red dots inside the blue cells) that are delivered to the HIV-infected cells and form large holes in their cell membrane, killing the infected cells. A small percentage of HIV-infected patients have killer T-cells that are extraordinarily efficient at this process. These patients do not require medications to control their disease and provide researchers with vital clues in understanding how killer T-cells attack HIV-infected cells.
The HIV-infected cells and killer T-cells were grown together in tissue culture. Different color stains were used to see various cells and structures in cells: blue for the killer T-cells, green for the HIV-infected cells, yellow for actin molecules, and red for the perforin granules. Images were collected at different depths using a confocal microscope and recombined digitally into a 3D-image.
Image courtesy of Blandine Monel, PhD and HHMI investigator Bruce Walker MD, Ragon Institute of MGH, MIT and Harvard
World AIDS Day is December 1 (http://www.aids.gov/news-and-events/awareness-days/world-aids-day/)