Provided are novel human-derived antibodies specifically recognizing polyomavirus polypeptides, preferably capable of binding to polyomaviruses of the type of JC virus (JCV) and/or BK virus (BKV) as well as methods related thereto. Furthermore, assays and kits related to antibodies specific for polyomaviruses, polyomavirus VP1 and or polyomavirus VP1 Virus-Like Particles (VLPs), preferably of the type of JCV and/or BKV, are disclosed. The human-derived antibodies as well as binding fragments, derivatives and variants thereof can be used in pharmaceutical and diagnostic compositions for polyomavirus targeted immunotherapy and diagnostics.