title: Did viruses play a part in the origin of the adaptive immune system?
authors.affiliation: Department of Biology, The Pennsylvania State University, Mueller Laboratory, University Park, Pennsylvania 16802-5301, USA.
authors.forename: J
authors.initials: J
authors.lastname: Klein
mesh_terms: D005075:Biological Evolution; D006801:Humans; D007110:Immunity, Active; D007113:Immunity, Innate; D008214:Lymphocytes / Q000276:immunology / Q000821:virology; D013950:Thymus Gland / Q000276:immunology / Q000821:virology; D018406:Virus Physiological Phenomena; D014780:Viruses / Q000276:immunology