Líffræðifélag Íslands
Líffræðiráðstefnan 2015

Erindi/veggspjald / Talk/poster E51

The adjuvant LT-K63 increases the frequency of eosinophils and megakaryocytes and their secretion of antibody-secreting cell survival factors in bone marrow of neonatal mice

Audur Anna Aradóttir Pind (1, 2) Stefanía P. Bjarnarson (1, 2), Giuseppe Del Giudice (3), Ingileif Jónsdóttir (1, 2, 4)

1. Department of Immunology, Landspitali, The National University Hospital, Reykjavik, Iceland, 2. Faculty of Medicine, University of Iceland, Reykjavik, Iceland, 3. Novartis Vaccines and Diagnostics (a GSK company), Siena, Italy, 4. deCODE genetics, Reykjavik, Iceland.

Kynnir / Presenter: Auður Anna Aradóttir Pind

Tengiliður / Corresponding author: Auður Anna Aradóttir Pind (audurap@landspitali.is)

The neonatal immune system is immature. Antibody (Ab) responses are slow and transient due to reduced survival of antibody-secreting cells (AbSCs) in the bone marrow (BM). The aim was to study the effect of neonatal immunization w/wo adjuvant on BM cell subsets and their production of AbSC survival signals APRIL and IL-6. We assessed the frequency of neutrophils, eosinophils (EOs), monocytes, macrophages and megakaryocytes (MKCs), as well as APRIL- and IL-6-secreting cells in BM by FACS at different time points after neonatal immunization with pneumococcal conjugate (Pnc1-TT) w/wo the adjuvant LT-K63. Vaccine-specific AbSCs in BM and serum Abs were determined by ELISPOT and ELISA. Frequency of MKCs and EOs, as well as APRIL- and IL-6-secreting MKCs and EOs was significantly increased in mice immunized with Pnc1-TT+LT-K63 compared to Pnc1-TT. Furthermore, the fraction of EOs that were APRIL+ and IL-6+ and MKCs that were APRIL+ was larger in mice immunized with Pnc1-TT+LT-K63. This correlates with higher vaccine-specific Ab levels and number of AbSCs that persist in mice that receive LT-K63 together with the vaccine. The results suggest that the adjuvant LT-K63 not only increases the number of EOs and MKCs in BM of neonatal mice but also activates a higher percentage of EOs to secrete APRIL and IL-6 and a higher percentage of MKCs to secrete APRIL. This might contribute to increased survival of AbSCs observed in BM at early age when LT-K63 is administered together with Pnc1-TT.