A primary HPV infection is cleared naturally in about 90% of the cases, suggesting that the immune system plays an important role in the protection against HPV-associated diseases, like cervical cancer. The HPV vaccines induce high HPV-specific antibody levels and memory B cell responses. Moreover, T-cells are known to be of importance in cell-mediated immunity. However, HPV-vaccine induced cell-mediated responses are not well understood after the HPV vaccination. We aim to investigate the cellular immune responses comparing non-infected, transient- and persistent infected young women.
In a longitudinal follow-up study, vaccinated and non-vaccinated young women were followed for 7 years post vaccination. From a part of all individuals peripheral blood monocytes (PBMC) were isolated (n=100 per year). Memory B-cell responses will be measured by HPV-serotype specific ELIspot assay using virus like particles, assembled from the major capsid protein L1 for HPV-16, HPV-18, HPV-31 and HPV-45. T-cell responses will be determined by cytokine production of stimulated PBMCs with HPV-specific peptides pools.
Memory B-cell responses and T-cell responses of participants with persistent HPV infection will be compared with those of participants who had no HPV infection or cleared their HPV infection. These immune responses will be further evaluated in the vaccinated and non-vaccinated groups. HPV-specific frequencies of memory B-cells will be determined and T-cell responses will be expressed in numbers of HPV-specific cytokine producing T-cells.
Obtained results will provide more insight and understanding in the immune mechanism of HPV-specific cellular responses.