FIG. 4.

Effects of heat and formalin on the coaggregation and coadherence of M. catarrhalis and S. pyogenes. S. pyogenes (Sp) was incubated alone or with biotinylated M. catarrhalis (bMc), heat-killed biotinylated M. catarrhalis, or formalin-killed, biotinylated M. catarrhalis. Cells were washed, and half of the cells were purified with streptavidin- magnetic beads and the other half were used in an adherence assay with A549 cells as described in the text. (A) S. pyogenes coaggregated with the live and formalin-killed, biotinylated M. catarrhalis cells but not with the heat-killed, biotinylated M. catarrhalis cells. (B) S. pyogenes adherence to A549 cells was also enhanced by the live and formalin-killed biotinylated M. catarrhalis cells but not by the heat killed, biotinylated M. catarrhalis cells. Strep., streptococcal.