International HPV Reference Center
The International Human Papillomavirus (HPV) Reference Center confirms DNA sequences of novel HPV types after the whole genomes have been cloned, assigns HPV type numbers, deposits and maintains the reference clones, as well as distributes samples of the reference material for research use (as far as allowed by the MTAs with the clone owners).

International HPV Reference Center (de Villiers et al.,2004; Bernard et al.,2010) was originally established at the German Cancer Research Center in Heidelberg in 1985 and was run under the leadership of Dr. Ethel-Michele deVilliers until 2012. In 2012, the International HPV Reference Center was transferred to the Karolinska Institutet, under the leadership of Dr. Joakim Dillner.
Human Papillomavirus Classification
HPV classification is based on the nucleotide sequence of the gene coding for the capsid protein L1 (de Villiers et al.,2004; Bernard et al.,2010):
- HPV types belonging to different genera share less than 60% similarity.
- Different HPV species within a genus share between 60 and 70 % similarity.
- A novel HPV type has less than 90% similarity to any other HPV type.
Reference clones
Human papillomavirus reference clones