Abstracts (complete list) - Wissenschaft Online

Oliver Winter, Katrin Moser, Nicole Haupt, Martin Szyska, Andreas Radbruch, Rudolf A.
Manz
PLASMA CELL SURVIVAL AND DEVELOPMENT IN THE BONE
MARROW
Plasma cells secrete antibodies which are a key factor for the adaptive immune defence.
Bone marrow is the major site where long-lived plasma-cells reside. Survival of these
cells in specific microenvironments (niche) depends on survival factors supplied by
proximate cells, including APRIL, IL-6, TNF-a. SDF-1+ reticular stromal cells found in
association with plasma cells are likely to contribute to this niche.
To further characterize these niches, we immunized B6 and Balb/c mice with the
antigen ovalbumin, sacrificed them at several time points during the immune response
and tracked ovalbumin specific plasma cells via confocal microscopy. Stromal cells
found in close association with plasma cells were considered to contribute potentially to
niches. These cells were further characterised by flow cytometry.
Plasma cells enter the bone marrow via the vascular niche. Here, they are found during
the first days following their immigration into the bone marrow in contact with B78+
cells of the endothelial linage, possibly including mature endothelial cells and endothelial
precursor cells. These plasma cells also make contact to Gr1 high cells, likely
resembling mature granulocytes emigrating from the bone marrow.
Later, at about 7 days after entering the bone marrow, plasma cells are found more
distant from B78+ cells. They now are localized adjacent to VCAM-1+ reticular stromal
cells where they also specifically bind to a particular type of myeloid related cells that
produce multiple important plasma cell survival factors, including Il-6, TNF-a and APRIL.
Our data suggest that following immigration of plasma cells via the vascular niche, longterm
plasma cell survival later is supported in a second niche. Here, VCAM+ reticular
stromal cells seem to provide a meeting point for long-lived plasma cells with myeloid
related cells that support plasma cell survival through the production of multiple
important plasma cell survival signals.