Abstracts (complete list) - Wissenschaft Online

Caspar Ohnmacht, Nico van Rooijen, David Voehringer
Cooperation between innate and adaptive immunity during
type 2 immune responses in vivo.
Type 2 immune responses are associated with allergic diseases and parasite infections.
They are mediated by IL-4/IL-13 expressing effector cells of the innate and adaptive
immune system. Using sensitive IL-4/eGFP reporter mice (4get mice) we could identify
eosinophils and basophils as the main IL-4 expressing cell types of the innate immune
system recruited to the lung during infection with the helminth parasite Nippostrongylus
brasiliensis or OVA-induced allergic inflammation. Reconstitution of T cell-deficient mice
with IL-4/IL-13-deficient CD4+ T cells was sufficient to mediate parasite expulsion from
the intestine and induction of effector cell recruitment and airway hyperreactivity in the
lung. Therefore, innate IL-4/IL-13 expressing cells play a crucial role during the effector
phase of type 2 immune responses.
We analyzed development, migration and turnover of eosinophils and basophils in vivo.
Both cell types could be identified in the fetal liver. Staining for the surface markers
FIRE, CCR3, Siglec-F and CD62L revealed a gradual maturation process of eosinophils
and enabled us to determine the activation status of eosinophils in different tissues.
Eosinophils showed an activated phenotype in lymph nodes, thymus and Peyers’
patches indicating that they had entered these tissues via the afferent lymph from sites
of inflammation. In contrast to basophils, eosinophils actively migrated to the peritoneal
cavity, where they survived for several days and from where they could recirculate to
other organs.