B cells are the weapons factories for our immune system. They produce antibodies, which lock on to a virus’s specific fingerprint, its antigen, marking it out for neutralisation by other immune cells. Here we see spleens from two different mice, where B cells are being ‘briefed’ on what their viral enemy looks like. The B cells (stained red) measure 1/2000 of a centimetre across and gather at hubs in the spleen. Here they are shown the virus’s antigen by specialised cells (stained blue). Only those B cells producing the most accurate antibodies survive this training and reproduce in large numbers (stained green). On the right we see the spleen of a mouse lacking a protein called Dicer, without which the B cells are unable to multiply.
Written by John Ankers
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