Co-culture of S. aureus and A. graevenitziimodulates innate immune responses
Given that co-culture with oral flora like A. graevenitziiappeared to suppress S. aureus growth, we hypothesized that this
interaction may also modulate innate immune responses to S.
aureus. To test this, we measured neutrophil recruitment to co-culture
of S. aureus and A. graevenitzii compared to mono-cultures
of S. aureus or A. graevenitzii alone. As previously
reported[17], S. aureus mono-cultures induced robust
recruitment of neutrophils into the culture chamber (Fig. 6B).
Importantly, this response was significantly blunted for co-cultures
containing A. graevenitzii (Fig. 6B). Interestingly, recruitment
of neutrophils to to co-cultures was also lower compared to A.
graevenitzii mono-cultures (Fig. 6B), suggesting that compounds
released during co-culture modifiy the microenvironment and influence
neutrophil responses. It is also possible that the two species become
less active / more quiscent, and thus they stimulate neutrophils less
than exponentially growing cultures.