Quantifying circulating antibody activities against the emerging environmental pathogen, Streptococcus agalactiae, in wild captured bull sharks, spotted eagle rays, bottlenose dolphins, and loggerhead turtles

Abstract

Global Streptococcus agalactiae and related pathogen infections are increasing, and place both wildlife species and humans at risk. Notably, Streptococcus agalactiae is now considered to be an emerging and zoonotic pathogen. Mouse monoclonal antibodies (mAbs) were generated against bull shark, Carcharhinus leucas, and spotted eagle ray, Aetobatus narinari, IgM, and bottlenose dolphin, Tursiops truncatus, IgG. Along with a previously generated mAb against loggerhead, Caretta caretta, IgY, these biological reagents were used to compare the sensitivity of relative antibody titers at sample dilutions of 1:200 in buffer to calculated antibody activities against whole cell Streptococcus agalactiae in wild captured individuals. Robust antibody responses were observed in each species, though some individuals differed significantly depending on whether viewed as relative antibody titers at sample dilutions of 1:200 or as antibody activities. The data from this study indicate that calculated antibody activities are more informative than relative antibody titers in determining antibody responses despite being more labor-intensive, expensive, and time consuming. This study provides several novel antibody reagents to the greater community of comparative immunologists, with a particular application to monitoring sentinel species for exposure to new emerging and zoonotic pathogens.