Heterogeneity of human papilloma viruses

Two types of human papilloma viruses (HPV-1 and HPV-4) were characterized, which show no relationship as far as the following criteria are concerned: the pattern of restriction enzyme fragments of their DNA, DNA-cRNA hybridization, and complement fixation with specific rabbit antisera. Furthermore, the molecular weights of the major proteins differed significantly. Both types of viruses could be isolated from plantar warts and from verrucae vulgares. This paper gives the molecular weights of the major proteins of a third type of HPV from skin warts, which reacts neither with HPV-1 nor with HPV-4 rabbit antiserum.