Detection of HPV types and neutralizing antibodies in Gansu province, China

A total of 82 samples from patients with cervical cancer (Group 1) and 50 samples from patients with other genital diseases (Group 2) were collected in Gansu, China. All 132 samples were tested for HPV DNA with a typing kit that can detect 21 types of HPV, and also tested for neutralizing antibodies against HPV-16, -18, -58, -45, -6, and -11 using pseudovirus-based neutralization assays. The results revealed that 28% (23/82) of sera in Group 1 were positive for type-specific neutralizing antibodies with a titer range of 160-640, of which 23.2% (19/82), 2.4% (2/82), 2.4% (2/82), 1.2% (1/82), and 1.2% (1/82) were against HPV-16, -58, -6, -18, and -45, respectively. Only one serum (2%) in Group 2 was positive for neutralizing antibodies, which were against HPV-6 with a titer of 2,560. Overall, 85.4% (70/82) of samples in Group 1 were HPV DNA-positive, compared with 28% (14/50) of samples in Group 2. The seven most common types detected in Group 1 were HPV-16 (80%), HPV-52 (7.1%), HPV-66 and HPV-11 (5.7% each), and HPV-58, HPV-18, and HPV-33 (4.3% each), while the four most common types in Group 2 were HPV-16 (12%), HPV-52 and HPV-11 (6% each), and HPV-68 (4%). The concordance between HPV DNA and corresponding neutralizing antibodies was 32.9% (27/82) with a significant difference (P < 0.005). More specifically, the concordance was 42.7% (35/82) for HPV-16 in Group 1. The full-length sequences of six HPV types (HPV-16, -58, -33, -59, -11, and -68) were determined and showed 99% identities with their reported genomes.