Finn-Eirik Johansen (Secretory Immunity and B-cells)
Group Leader: Finn-Eirik Johansen Ph.D.
Group Members:
Per Brandtzæg (PhD, consultant)
Ranveig Braathen, PhD student – defended thesis in 2006
Alex Erofeev (MD, PhD student)
Anna Lång (BSc, PhD student)
Else Munthe (PhD, postdoc)
Anders Sandvik (BSc, PhD student)
Dag Henrik Reikvam (MD, PhD student)
Active polymeric Ig receptor (pIgR)-mediated epithelial transport of dimeric IgA and pentameric IgM, generates secretory IgA (SIgA) and SIgM antibodies, respectively. Such secretory antibodies provide immune exclusion of micro-organisms and are important for mucosal homeostasis. The section has continued its focus on regulation and function of secretory antibodies as well as the therapeutic potential of mucosal delivery of β-glucans as a modulator of immunity. A chemically induced colitis model was employed in our pIgR knockout mice, which lack secretory antibodies, and demonstrated that they were considerable more afflicted than wild type mice. We also demonstrated that oral feeding of β-glucan reduced the severity of organ injury in a rat model of endotoxin-mediated sepsis.
Appropriate polymerization of IgA and its binding to the pIgR require incorporation of the small J-chain polypeptide. We have continued to analyze the direct role of J chain in this interaction and its phylogenetic conservation. Furthermore we demonstrated the presence of a functional pIgR in Xenopus laevis, the first amphibian and most distant pIgR to humans found to date.