Microbial killing ability
To quantify constitutive innate immune function, the important less specific first line of defence (Janeway, Travers, Walport, & Shlomchik, 2005), we measured microbial killing ability. This assay measures the degree to which an individual’s innate immune system can eradicate pathogens, in this case the gram-negative bacteria Escherichia coli . It thus represents a broad and integrative measure of innate immune function. We followed the protocol described by French and Neuman-Lee (2012) along with some modifications by Eikenaar and Hegemann (2016). Volumes of 3μl plasma and 4μl of 1.06x10^6 E. coli were finalized as optimal volumes for these species after running several test plates. The absorbance was measured using a FLUOstar Omega microplate reader.