Sustained control of group A Streptococcus (GAS)
infections in settings of poverty has proven to be challenging, and an effective
vaccine may be the most practical long-term strategy to reduce GAS-related disease burden. Candidate GAS
vaccines based on the
J8 peptide have demonstrated promising immunogenicity in mice, however, less is known about the role of
J8 antibodies in the human immune response to GAS
infection. We analysed the stimulation of
J8 antibodies in response to
infection, and the role of existing
J8 antibodies in protection against subsequent
infection, using data collected in the Fijian population: (1) cross sectional population serosurvey; (2) paired serum collection for assessment of M-specific and
J8 antibody responses; and (3) longitudinal assessment of GAS
infection and immunity. Median
J8 antibody concentrations peaked in the 5-14 year age group, but there was no sustained increase with age.
J8 antibody concentration was neither a significant predictor of time to next
infection, nor did it show any relationship to the time since last recorded skin
infection. Similarly,
J8 antibody fold changes over a defined period were associated neither with the time since last skin
infection, nor the number of intervening skin
infections. While strong M-specific antibody responses were observed for skin
infection, similarly strong
J8 antibody responses were not observed. There is no indication that
antibodies to the
J8 antigen would be useful as either a marker of GAS
infection or a measure of population immunity, with
J8 antibody responses to
infection fleeting, if existent at all.