Main author: Jenny Lorena Molina Estupiñan
Institution or Company: University of Iceland, Landspítali the National University Hospital of Iceland
Co-Authors, Institution or Company:
Auður Anna Aradóttir Pind, University of Iceland, Landspítali the National University Hospital of Iceland. Jan Holmgren, University of Gothenburg Vaccine Research Institute (GUVAX), Sahlgrenska Academy, Sweden.. Ingileif Jónsdóttir, University of Iceland, Landspítali the National University Hospital of Iceland. Stefanía P. Bjarnarson, University of Iceland, Landspítali the National University Hospital of Iceland.
Introduction: Inexperienced and poorly developed immune system of neonates contributes to increased susceptibility to infectious diseases and poor vaccine responses. The aim of the study was to compare the effects of the adjuvants mmCT and dmLT on neonatal antibody response to subcutaneous and intranasal immunization with a pneumococcal conjugate vaccine Pn1-CRM197.
Methods: Neonatal mice were immunized subcutaneously or intranasally with 0.75µg of Pn1-CRM197, with or without dmLT or mmCT, at 2 or 5µg per dose. Serum was collected at different time points after immunization for measurements of PPS-1-specific IgG antibodies by ELISA.
Results: Antibody levels of neonatal mice immunized subcutaneously with 0.75μg of Pn1-CRM197 were low. However, mice immunized with Pn1-CRM197 and 2µg of dmLT had significantly higher levels of antibodies 14, 28 and 56 days after immunization. Mice immunized with Pn1-CRM197 and 2μg of mmCT had significantly higher levels antibodies 14, 28, 42 and 56 days after immunization. The 5µg dose of either adjuvant enhanced antibody levels even further, although not significantly higher than when 2μg of adjuvants were given. Intranasal immunization with 2μg of dmLT or mmCT with Pn1-CRM197 slightly increased the antibody response. However, Pn1-CRM197 with 5μg of either adjuvant, dmLT or mmCT, elicited significantly higher antibody responses 28, 42 and 56 days after intranasal immunization than Pn1-CRM197 alone.
Conclusion: The adjuvants dmLT and mmCT enhanced the antibody response induced by the vaccine Pn1-CRM197, both subcutaneously and intranasally. These results demonstrate that dmLT and mmCT are promising adjuvants for early life vaccination.
