At the front line of mammalian defence against viruses are special white blood cells known as T-cells. T-cells can seek out and destroy those of our cells that have succumbed to viral infection. Here we see the aftermath of a battle with a viral infection fought on a microscopic scale in mouse spleen cells. An ultra-fine sliver of spleen is shown here with nuclei stained blue (white box, magnified top left, measures 1/200 cm across). Following infection with a virus, some of these spleen cells sent out a chemical distress signal called an alarmin (in this case a specific protein called interleukin-33 shown in green). The signal effectively rallies the troops – a cavalry of protective T-cells (here coloured red) – to prevent the virus from advancing.
Written by John Ankers
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