In the present study, the selection of the 1 M concentration of NaSCN was a conservative www.selleckchem.com/EGFR(HER).html choice to avoid potential artefacts associated with higher concentrations, such as the modification of antigen structural components (e.g. the disruption of conformational epitopes; or the instability of antigen attachment to the ELISA plate: see [29] in which Guanidine HCl and

NH4SCN were evaluated). The relevance of the avidity ELISA in this study was confirmed by detecting HPV16 and HPV18 L1-specific AI increases at post-Dose 3 (Month 7) compared with post-Dose 2 (Month 2). These increases were in line with a previous study of the same vaccine [10] and with the anticipated affinity maturation of vaccine-antigen specific antibodies [21] and [22]. The impact of the interval

www.selleckchem.com/products/DAPT-GSI-IX.html between Dose 1 and Dose 2 in the 2-dose schedule on the magnitude of the AI was not evaluated. Although the data suggested that HPV16 and HPV18 L1-specifc AIs were higher one month after Dose 2 in a 0, 6 month schedule than in a 0, 1 month schedule, the length of time after Dose 1 (seven months rather than two months) may have also contributed to the magnitude of the AIs [28]. The absence of strong correlations between AIs and absolute antibody concentrations concurred with other published observations, in that the magnitude and quality of the antibody response are not temporally associated [9], [10] and [11]. In one of those studies, HPV16 L1-specific AIs were only correlated with neutralisation responses at one of the several time points examined over a 36-month post-vaccination period [10]. Furthermore, although the magnitude of absolute high-avidity antibody concentrations at Month 7 appeared to vary with the age of the vaccine recipient, the AI appeared unaffected. Therefore, this suggests that antibody Bay 11-7085 quality (as measured by AI) is not highly

linked to antibody quantity. Instead, the magnitude of the AI may reflect the magnitude of certain aspects of the T cell response including the involvement of TFH cells in the clonal selection of B-cell populations, such as B-memory cells and plasma cells, with high-affinity for the antigens [31]. Moreover, the induction of persistent B-memory and T cells after immunisation with HPV-16/18 vaccine has been demonstrated in several studies [11], [32] and [33]. Hence further investigations could be conducted to identify the relationship between the avidity of HPV L1-specific antibodies, their functional activity and the induction of B-memory and T cells. In the absence of clinical efficacy data in the 9–14 year olds, the assessment of the antibody concentration and quality in this population is crucial.