Image of the month:
Lymphocytes and platelets isolated from human blood
This coloured scanning electron microscopic image depicts lymphocytes (green) and platelets (grey). The lymphocytes were isolated by Ficoll density centrifugation as a fraction from whole blood and are the most abundant cells in the lymph, hence their name. They constitute the white blood cells, which are composed in any vertebrate immune system by three cell types: the natural killer cells (cell-mediated, cytotoxic innate immunity, the T cells (cell mediated, cytotoxic adaptive immunity and the B cells (humoral, antibody-driven adaptive immunity.