Bovine papillomavirus (BPV) is the etiological agent of bovine
papillomatosis,
infectious disease characterized by the presence of benign
tumors that can progress to
malignancy. The phylogenetic
classification of the PVs is performed based on the
sequence homology of the
Open Reading Frame L1, the most conserved among different viral
serotypes. Given the immunogenicity of
saponins, it,s has been used as a candidate as adjuvant use. For this reason, the
safety of using
saponin as an adjuvant has to be better determined to
human or
veterinary vaccine use. So, this study aimed to evaluate the mutagenic and genotoxic effect of
saponins in comparison with the adjuvant widely used
aluminum hydroxide using an isolated and purified L1
protein from BPV as model. In this study, genomic lesions, which after processed without repair can result in
mutations, were detected by
comet assay. Possible damages to
genetic material caused by structural chromosomal changes (clastogenesis), as well as chromosomal losses (aneugenesis) were evaluated by the
micronucleus test. Both tests were done on polychromatic
erythrocytes and
Vero cells. The evaluation of
apoptosis and
necrosis of treated
Vero cells was made by
Annexin V / PI
staining and
flow cytometry. The two
vaccine products (L1 +
Saponin and L1 +
Aluminum Hydroxide) showed damages compatible with the positive control in the
comet assay and both slightly elevated the micronucleus levels, in the
Cell Viability Assay the results with
Aluminum Hydroxide were satisfactory, characterizing
Aluminum Hydroxide as a safer adjuvant according to the proposed tests, better than the
saponins. Some fractions of the
saponin extract
separated by
High Performance Liquid Chromatography were evaluated against genotoxic activity by
comet assay, and their identities were confirmed by similarity to the
reference standard by
mass spectrometry.