IL-10 secreting [CD21.sup.+] B cells are present in jejunal Peyer's patches of sheep during fetal development

• Published in: Cell and tissue research 2014-05, Vol.356 (2), p.417
• Main Authors: Jimbo, S, Griebel, P.J, Babiuk, L, Mutwiri, G
• Format: Article
• Language: English
• Subjects: B cells; Biological response modifiers; Fetus; Growth; Interferon; Interleukins
• ISSN: 0302-766X
• DOI: 10.1007/s00441-014-1803-2

We recently reported a novel interleukin-10 (IL-10)-secreting [CD21.sup.+] B cell population in jejunal Peyer's patches (JPP) of sheep with a regulatory function ([B.sub.regs]) suppressing Toll-like receptor 9 (TLR9)-induced cytokine responses. However, little is known about the development of these cells. Therefore, we investigate their existence in JPP cells from fetal and newborn lambs. [CD21.sup.+] B cells were purified from JPP cells by magnetic cell sorting and subsequently stimulated with the TLR9 agonist, CpG ODN (CpG oligodeoxynucleotide). Lymphocyte proliferative responses, cytokine production (IL-10, IL-12 and interferon-γ [INF-γ]) and antibody secretion were assayed. We found that fetal and neonatal [CD21.sup.+] B cells spontaneously secreted high levels of IL-10 regardless of CpG stimulation but that these cells did not produce any IL-12 or INF-γ upon stimulation with CpG. The observed responses are consistent with those previously reported for [B.sub.regs] characterized in JPP of older lambs. Surprisingly, unlike in older lambs, fetal and neonatal JPP [CD21.sup.+] B cells proliferated in response to CpG stimulation. Our investigations of fetal and neonatal lambs provide evidence for the development of IL-10-secreting [CD21.sup.+] B cells in PPs prior to antigen exposure. Keywords Immune regulation, Regulatory cells, [B.sub.regs], Peyer's patches, TLR9, CpGODN, Sheep