Effect of neonatal sublingual vaccination with native or denatured ovalbumin and adjuvant CpG or cholera toxin on systemic and mucosal immunity in mice

Sublingual immunotherapy has been applied for allergic diseases, but whether sublingual immunization in neonates can prevent sensitization has not been studied. In this study, we evaluate the effect of neonatal sublingual vaccination with native or denatured allergens alone or plus adjuvant on allergy prevention. Newborn BALB/c mice were sublingually vaccinated daily for the first 3 days with native or denatured ovalbumin (OVA) only, or combined adjuvant CpG or cholera toxin (CT). They were sensitized with OVA adsorbed onto alum 7 weeks after the last vaccination. Specific secretory IgA antibody responses were readily induced by neonatal vaccination with antigen plus CpG or CT, but not with antigen alone. Whereas vaccination with denatured OVA plus CpG markedly enhanced T helper 1 (Th1) responses and inhibited IgE production, vaccination with denatured OVA plus CT increased cervical lymph node cell production of interleukin-4 (IL-4), IL-5, IL-6, and serum IgG1 responses. These data demonstrate that neonatal sublingual vaccination with denatured OVA and CpG not only preferentially induces systemic Th1 responses and mucosal immunity, but also simultaneously abrogates IgE production. Neonatal sublingual vaccines may play a role for the strategy of allergy prevention.