Illustration of the DNA (deoxyribonucleic acid) vaccine (plasmid) entering an antigen presenting cell (dendritic cell). The DNA is transported into the nucleus, where it is transcribed into mRNA (messenger ribonucleic acid) and then subsequently translated into antigen proteins, which then undergo further processing to generate antigen peptides. The vaccine can generate both B cell and T cell responses. For a version of this image without labels see F042/5627.