INTU and infection: In addition, to control for possible nonspecific attenuating effects of plasmid insertion in the GAS chromosome or potential excision of the plasmid from the chromosome during infection, a second group of five animals was co-infected with similar doses of 003Sm and integrant strain 003Sm-Int-WT in which pJLperRΔ integration had occurred immediately downstream, and not upstream, of perR (Figure 1).