Figure 4. Killing of NTS and anti-Salmonella IgG and IgM titers for serum from Malawian children.

(A) In vitro killing of S. Typhimurium isolate D23580 at 180 minutes (initial concentration 10⁶ salmonellae/ml), (B) anti-Salmonella D23580 IgG levels, and (C) anti-Salmonella D23580 IgM levels for sera from 65 healthy Malawian children compared with age. Each point corresponds to serum from 1 child. Numbers at top right denote the number of points in the indicated quadrants, as divided by patient age (more or less than 16 months) and normal or impaired killing (more or less, respectively, than 1.2 log₁₀ kill or 1.5 U Ig titer as appropriate).