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.