Identification of a viral agent such as HPV as a cause of disease(s) implies that successful prophylactic or therapeutic intervention against the viral agent should prevent the disease(s) it causes. Successful antivirals have been developed for the treatment of some viral infections, including diseases such as HIV and influenza, but not against viruses such as papillomavirus.
Autologous vaccination, in which a wart is removed, made into a crude vaccine, and injected into the same animal, has been used in the treatment of warts since 1960. The technique has been reported to be effective in the prevention and the treatment of canine papillomas. However, vaccination with “live” COPV extract results in occasional development of various epithelial neoplasms, including squamous cell carcinoma, at the injection sites.
VLP vaccines for COPV (CPV1) and CfPV2 (CPV2) have been developed recently.
The canine papillomavirus VLP vaccines are purified recombinant canine papillomavirus L1 protein.The purified L1 proteins form a structure called virus-like particle (VLP). Structure-wise there is almost no difference between VLPs and real viruses. However, since the VLPs are lacking the viral genes (autologous vaccine still has viral genes) which may casue disease in animals, the VLPs are safe for use. The VLPs contain the immunodominant neutralization epitopes of the virus. After the dogs receive the vaccines, it will develop immunities against the virus infection. Although it is still an experimental vaccine, it have been used effectively on thousands dogs each year as a preventative vaccine. The same VLP technique is currently used for the production of HPV/cervical cancer vaccine, which is approved by FDA.
An existing viral infection can theoretically be targeted by a therapeutic vaccine. As a therapeutic vaccine, the canine papillomavirus vaccine seems to work the best when used right after wart removal surgery. There is no guarantee that the vaccine is going to work. Some dogs responded positively. For those dogs, most of them had vaccination right after surgery. Those big lesions are really hard to resolve by the immunoresponse without surgery.
Some publications on canine papillomavirus vaccines:
Suzich JA, Ghim SJ, Palmer-Hill FJ, White WI, Tamura JK, Bell JA, Newsome JA, Jenson AB, Schlegel R. Systemic immunization with papillomavirus L1 protein completely prevents the development of viral mucosal papillomas.Proc Natl Acad Sci U S A. 1995 Dec 5;92(25):11553-7.PMID: 8524802
Yuan, H., P.A. Estes, Y. Chen, J. Newsome, V.A. Olcese, R.L. Garcea, and R. Schlegel, Immunization with a pentameric L1 fusion protein protects against papillomavirus infection. J Virol, 2001. 75(17): p. 7848-53. (PMID: 11483728)
Kuntsi-Vaattovaara, H., F.J. Verstraete, J.T. Newsome, and H. Yuan, Resolution of persistent oral papillomatosis in a dog after treatment with a recombinant canine oral papillomavirus vaccine. Vet Comp Oncol, 2003. 1(1): p. 57-63. (PMID: 19379331)