Abstract
Background
Research on the origins and development of human IgE-expressing (IgE+) cells is required for understanding the pathogenesis of allergy and asthma. These studies have been thwarted by the rarity of IgE+ cells in vivo and the low frequency of class switch recombination (CSR) to IgE ex vivo. To determine the main source of IgE+ cells we investigated the relation between the phenotypic composition of tonsil B cells and the CSR to IgE ex vivo.
Methods
Human tonsil B cells were analysed by flow cytometry (FACS) and cultured with IL-4 and anti-CD40 to induce CSR to IgE. Naïve, early germinal center (eGC), GC and memory tonsil B cells were isolated by FACS and their capacities for IL-4 and anti-CD40 signaling, cell proliferation and de novo class switching to IgE were analyzed by RT-PCR and FACS.
Results
B cells from different tonsils exhibited varying capacities for CSR to IgE ex vivo. This was correlated with the percentage of eGC B cells in the tonsil at the outset of the culture. Despite relatively poor cell viability, eGC and GC B cell cultures produced the highest yields of IgE+ cells compared to naïve and memory B cell cultures. The main factors accounting for this result were the strength of IL-4R and CD40 signaling and relative rates of cell proliferation.
Conclusions
This study shows that the maturation state of tonsil B cells determines their capacity to undergo class switching to IgE ex vivo, with the GC derived B cells yielding the highest percentage of IgE+ cells.
Research on the origins and development of human IgE-expressing (IgE+) cells is required for understanding the pathogenesis of allergy and asthma. These studies have been thwarted by the rarity of IgE+ cells in vivo and the low frequency of class switch recombination (CSR) to IgE ex vivo. To determine the main source of IgE+ cells we investigated the relation between the phenotypic composition of tonsil B cells and the CSR to IgE ex vivo.
Methods
Human tonsil B cells were analysed by flow cytometry (FACS) and cultured with IL-4 and anti-CD40 to induce CSR to IgE. Naïve, early germinal center (eGC), GC and memory tonsil B cells were isolated by FACS and their capacities for IL-4 and anti-CD40 signaling, cell proliferation and de novo class switching to IgE were analyzed by RT-PCR and FACS.
Results
B cells from different tonsils exhibited varying capacities for CSR to IgE ex vivo. This was correlated with the percentage of eGC B cells in the tonsil at the outset of the culture. Despite relatively poor cell viability, eGC and GC B cell cultures produced the highest yields of IgE+ cells compared to naïve and memory B cell cultures. The main factors accounting for this result were the strength of IL-4R and CD40 signaling and relative rates of cell proliferation.
Conclusions
This study shows that the maturation state of tonsil B cells determines their capacity to undergo class switching to IgE ex vivo, with the GC derived B cells yielding the highest percentage of IgE+ cells.
| Original language | English |
|---|---|
| Pages (from-to) | 1269-1277 |
| Number of pages | 9 |
| Journal | Allergy |
| Volume | 70 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - 25 Oct 2015 |
