Detailed comparisons of the antibacterial IgA reactivity from donors collected over two separate infants. Paired Student’s t tests comparing the antibacterial IgA binding between breast milk collected from the first and second infant. Each dot represents a different bacterial taxon and each graph is a different donor dyad (as indicated). The right-hand graph is the difference (norm. IgA binding infant 2 − norm. IgA binding infant 1) for each taxon. This experiment was performed once.