Neonate intestinal immune response to CpG oligodeoxynucleotide stimulation

Area of Science:

• Immunology
• Vaccinology
• Neonatal Research

Background:

• Mucosal vaccines are vital for controlling infections entering through mucosal surfaces.
• Effective mucosal adjuvants are lacking, hindering vaccine development.
• Synthetic oligodeoxynucleotides with cytosine-guanine motifs (CpG-ODN) activate TLR9 and show adjuvant potential, but their neonatal intestinal efficacy is unclear.

Purpose of the Study:

• To investigate the efficacy of CpG-ODN in stimulating the neonatal intestinal immune system.
• To compare oral versus intraperitoneal administration routes for CpG-ODN in neonates and adults.
• To elucidate the role of IL-10 in neonatal unresponsiveness to TLR9 stimulation.

Main Methods:

• Newborn mice received oral CpG-ODN; intestinal cytokine and chemokine responses were measured.
• Immunohistochemistry was used to detect cellular infiltration in neonate intestines.
• Intestinal immune responses to CpG-ODN were compared between neonates and adults via oral and intraperitoneal routes.

Main Results:

• Oral CpG-ODN induced chemokine responses and cellular infiltration in neonatal intestines.
• Neonates exhibited greater responsiveness to TLR9 stimulation than adults, regardless of administration route.
• Neonatal intestinal epithelial cells and lamina propria cells responded to TLR9 stimulation, producing chemokines and cytokines.

Conclusions:

• CpG-ODN administration, particularly intraperitoneally, is more effective in neonates than adults for stimulating intestinal chemokine responses, linked to lower neonatal IL-10 levels.
• The oral route effectively induces intestinal chemokine responses in neonates.
• These findings support the potential of CpG-ODN for developing neonatal mucosal vaccines.