CpG oligodeoxynucleotides stimulate cord blood mononuclear cells to produce immunoglobulins

CpG oligodeoxynucleotides (ODNs) stimulate adult B cells leading to cellular proliferation and immunoglobulin production. It is unknown if CpG-ODNs similarly stimulate neonatal human B cells. Neonates have immature immune responses and are poorly responsive to thymus independent antigens such as polysaccharides. We determined umbilical cord cells' response to CpG-ODNs. Adult and umbilical cord B cells produced similar amounts of IgM (adult 1371 +/- 352 vs. cord 1873 +/- 1084 ng/ml) in response to CpG-ODN stimulation. Although CpG-ODN was able to stimulate adult IgG and IgA production, cord cells produced less IgG (153 +/- 58 vs. 10 +/- 2.5 ng/ml) and no detectable IgA upon CpG-ODN stimulation. CpG ODN stimulated IgM production from adult CD27-negative B cells which may account for their ability to stimulate the mostly naïve cord B cells. The polyclonal IgM response included pneumococcal polysaccharide antigen-specific antibodies. CpG-ODNs may be useful as neonatal vaccine adjuvants for polysaccharide antigens that are otherwise non-immunogenic.