Study on development of HPV vaccine and the use for prevention of cervical cancer

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1. Neutralizing antibody against HPV L2 can cross-neutralize different HPV types in vitro. To identify the segments containing the cross-neutralization epitopes of HPV16 L2, we characterized antisera (AS) obtained by immunizing two rabbits with each of the ten synthetic peptides of 14 to 20 amino acids (aa) long, which represents a part of the HPV16 L2 sequence from aa 14 to 144. The AS against the peptides bound to HPV16 L1/L2-capsids and neutralized HPV16 pseudovirions. AS against the peptide from aa 18 to 38 (anti-P18/38) cross-neutralized HPV18. Anti-P56/75 cross-neutralized HPV18, 31, and 58. Anti-P61/75 and anti-P64/81 cross-neutralized HPV18 and 58. Anti-P96/115 and the AS induced by a mutant P96/115 cross-neutralized HPV31 and 58. The mixture of equal volumes of three AS, anti-P18/38, anti-P56/75, and anti-mutant P96/115, neutralized HPV16, 18, 31, and 58 more efficiently than anti-P56/75 alone. The cross-neutralization appears to be correlated with conserved aa sequences among … More HPV types. The data provide a basis for designing vaccine antigens effective against a broader spectrum of the high-risk HPVs.2. Production of HPV16 Ll in undifferentiated cells is negatively regulated by several yet unidentified cis-acting inhibitory RNA elements (ELs), among which a major EL is located within the first 514 nucleotides of the Ll-mRNA. By Northern blotting we examined effect of the major EL on the steady-state level of mRNA transiently transcribed in 293T cells from the firefly luciferase (Fluc) gene combined with the Ll DNA fragment encoding the major EL. The EL down-regulated steady-state level of the mRNA. The most efficient down-regulation was achieved by insertion of the EL near the 5' end of mRNA. The half-life of the mRNA having the EL was similar to that of normal Fluc-mRNA. When the EL near the 5' end was removed by splicing, the steady-state level of the resultant mRNA was raised to a readily detectable level. It is suggested that DNA region encoding the major inhibitory EL does not disturb transcription and that the pre-mRNA is degraded by an RNA EL-mediated mechanism after the splicing step in the course of mRNA maturation. Less