FIG. 1.

Agglutination of various strains of E. coli in the presence of SIgA. The numbers and sizes of particles after the addition of 0.5 mg of SIgA/ml to various strains of E. coli (ORN225, ORN226, and ORN227; see Table 1) were measured as a function of time with a Coulter counter. For presentation purposes, smaller aggregates (3 to 6 μm) (A) were plotted separately than larger aggregates (>6 μm) (B), which formed slower than the smaller aggregates. Experiments were performed in duplicate, and the standard errors are shown.