Johannes Stöckl and Otto Majdic

Aachoo! A cold again? Everyone goes through 3- 4 colds a year, most of them caused by human rhinoviruses. Besides being bothersome, colds are an economical factor due to employee's illness. At first the immune response during a cold seems to be exaggerating as produced cytokines lead to strong symptoms. But further on secondary infections and the lacking induction of protective immunity suggest a diminished immune function. Therefore one focus of our group lies in studying the effects of human rhinovirus on leukocytes and identifying immunologically important molecules involved.

Dendritic cells (DC) are sophisticated gatekeepers for detecting invading pathogens and eliciting an appropriate immune response. We observed that DC are not productively infected by rhinovirus, but loose their T-cell stimulatory function upon interaction with rhinovirus. Using monoclonal antibodies against rhinovirus-treated DC we could identify the surface molecules B7-H1 and Siglec-1 on DC contributing to this poor stimulatory capacity. Furthermore we found that T cells cocultered with rhinovirus-treated DC become anergic and show a regulatory function by secretion of inhibitory factors. As prominent inhibitory cytokines like IL-10 and TGF-beta are not responsible we are currently trying to identify new immune-regulatory factors using immuno-proteomics.