Dose-sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse model

Childhood vaccination provides protection against infectious diseases, but multiple vaccinations are required to achieve this. In situations like influenza epidemics or COVID-19 pandemic, vaccine demands may exceed production capacity, highlighting the need for dose-sparing strategies. Adjuvants can...

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Main Authors: Jenny Lorena Molina Estupiñan, Poorya Foroutan Pajoohian, Gabriel Kristian Pedersen, Dennis Christensen, Serena Marchi, Emanuele Montomoli, Stefanía P. Bjarnarson, Ingileif Jonsdottir, Audur Anna Aradottir Pind
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-07-01
Series:Frontiers in Immunology
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Online Access:https://www.frontiersin.org/articles/10.3389/fimmu.2025.1646677/full
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author Jenny Lorena Molina Estupiñan
Jenny Lorena Molina Estupiñan
Poorya Foroutan Pajoohian
Poorya Foroutan Pajoohian
Gabriel Kristian Pedersen
Dennis Christensen
Serena Marchi
Emanuele Montomoli
Emanuele Montomoli
Stefanía P. Bjarnarson
Stefanía P. Bjarnarson
Ingileif Jonsdottir
Ingileif Jonsdottir
Audur Anna Aradottir Pind
Audur Anna Aradottir Pind
author_facet Jenny Lorena Molina Estupiñan
Jenny Lorena Molina Estupiñan
Poorya Foroutan Pajoohian
Poorya Foroutan Pajoohian
Gabriel Kristian Pedersen
Dennis Christensen
Serena Marchi
Emanuele Montomoli
Emanuele Montomoli
Stefanía P. Bjarnarson
Stefanía P. Bjarnarson
Ingileif Jonsdottir
Ingileif Jonsdottir
Audur Anna Aradottir Pind
Audur Anna Aradottir Pind
author_sort Jenny Lorena Molina Estupiñan
collection DOAJ
description Childhood vaccination provides protection against infectious diseases, but multiple vaccinations are required to achieve this. In situations like influenza epidemics or COVID-19 pandemic, vaccine demands may exceed production capacity, highlighting the need for dose-sparing strategies. Adjuvants can boost and modulate immune responses to vaccines and could reduce the antigen doses needed to confer protection. Herein we evaluated the dose-sparing effects of the novel adjuvants dmLT, mmCT, CAF01, and CAF08b and alum (aluminum hydroxide) on primary neonatal antibody (Ab) response to a conjugate vaccine against Streptococcus pneumoniae, Pn1-CRM197, and a recombinant influenza hemagglutinin (HA) protein vaccine. The primary Ab levels of neonatal mice immunized once with a full dose of Pn1-CRM197 or HA were low. mmCT and CAF08b enhanced Pn1-specific IgG Abs elicited by fractional doses of Pn1-CRM197, providing eightfold dose sparing of the vaccine, whereas dmLT and CAF01 provided fivefold and twofold dose sparing, respectively. These adjuvants elicited protective Pn1-specific Ab levels against bacteremia (91%–63%) and pneumonia (50%–38%) in neonatal mice when combined with a half-dose of Pn1-CRM197. In addition, mmCT, CAF01, and CAF08b enhanced the persistence of Pn1-specific IgG Ab-secreting cells (ASCs) in bone marrow compared with a full dose of vaccine only. With the influenza HA vaccine, CAF08b provided 40-fold dose sparing, while CAF01 and mmCT provided twofold dose sparing. CAF08b induced the micro-neutralization (MN) titers above protective levels in 100% and 86% of mice receiving 1/8 and 1/40 of HA dose, respectively, and CAF01 in 88% and 50% of mice receiving 1/4 and 1/8 dose of HA, respectively, whereas only 38% of mice receiving a full-dose HA without adjuvant reached the protective MN levels. Furthermore, these adjuvants provided cross-protective Abs and ASCs against a closely related heterologous influenza strain. In contrast, aluminum hydroxide did not provide any dose-sparing effects. Collectively, our results demonstrate that mmCT, CAF01, and CAF08b enhanced the protective humoral responses and had large dose-sparing effects on both Pn1-CRM197 and HA vaccines, although the adjuvant effect was clearly vaccine-dependent. The results support the potential use of safe adjuvants in situations when vaccine production capacity is limited, including vaccination of pediatric populations that may be of high risk.
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spelling doaj-art-55bbf5fddb4046929ff95b8b7be7fe812025-08-20T02:46:28ZengFrontiers Media S.A.Frontiers in Immunology1664-32242025-07-011610.3389/fimmu.2025.16466771646677Dose-sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse modelJenny Lorena Molina Estupiñan0Jenny Lorena Molina Estupiñan1Poorya Foroutan Pajoohian2Poorya Foroutan Pajoohian3Gabriel Kristian Pedersen4Dennis Christensen5Serena Marchi6Emanuele Montomoli7Emanuele Montomoli8Stefanía P. Bjarnarson9Stefanía P. Bjarnarson10Ingileif Jonsdottir11Ingileif Jonsdottir12Audur Anna Aradottir Pind13Audur Anna Aradottir Pind14Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, IcelandDepartment of Immunology, Landspitali, the National University Hospital of Iceland, Reykjavík,  IcelandFaculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, IcelandDepartment of Immunology, Landspitali, the National University Hospital of Iceland, Reykjavík,  IcelandCenter for Vaccine Research, Statens Serum Institut, Copenhagen, DenmarkCenter for Vaccine Research, Statens Serum Institut, Copenhagen, DenmarkDepartment of Molecular and Developmental Medicine, University of Siena, Siena, ItalyDepartment of Molecular and Developmental Medicine, University of Siena, Siena, ItalyVisMederi, Siena, ItalyFaculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, IcelandDepartment of Immunology, Landspitali, the National University Hospital of Iceland, Reykjavík,  IcelandFaculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, IcelandDepartment of Immunology, Landspitali, the National University Hospital of Iceland, Reykjavík,  IcelandFaculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, IcelandDepartment of Immunology, Landspitali, the National University Hospital of Iceland, Reykjavík,  IcelandChildhood vaccination provides protection against infectious diseases, but multiple vaccinations are required to achieve this. In situations like influenza epidemics or COVID-19 pandemic, vaccine demands may exceed production capacity, highlighting the need for dose-sparing strategies. Adjuvants can boost and modulate immune responses to vaccines and could reduce the antigen doses needed to confer protection. Herein we evaluated the dose-sparing effects of the novel adjuvants dmLT, mmCT, CAF01, and CAF08b and alum (aluminum hydroxide) on primary neonatal antibody (Ab) response to a conjugate vaccine against Streptococcus pneumoniae, Pn1-CRM197, and a recombinant influenza hemagglutinin (HA) protein vaccine. The primary Ab levels of neonatal mice immunized once with a full dose of Pn1-CRM197 or HA were low. mmCT and CAF08b enhanced Pn1-specific IgG Abs elicited by fractional doses of Pn1-CRM197, providing eightfold dose sparing of the vaccine, whereas dmLT and CAF01 provided fivefold and twofold dose sparing, respectively. These adjuvants elicited protective Pn1-specific Ab levels against bacteremia (91%–63%) and pneumonia (50%–38%) in neonatal mice when combined with a half-dose of Pn1-CRM197. In addition, mmCT, CAF01, and CAF08b enhanced the persistence of Pn1-specific IgG Ab-secreting cells (ASCs) in bone marrow compared with a full dose of vaccine only. With the influenza HA vaccine, CAF08b provided 40-fold dose sparing, while CAF01 and mmCT provided twofold dose sparing. CAF08b induced the micro-neutralization (MN) titers above protective levels in 100% and 86% of mice receiving 1/8 and 1/40 of HA dose, respectively, and CAF01 in 88% and 50% of mice receiving 1/4 and 1/8 dose of HA, respectively, whereas only 38% of mice receiving a full-dose HA without adjuvant reached the protective MN levels. Furthermore, these adjuvants provided cross-protective Abs and ASCs against a closely related heterologous influenza strain. In contrast, aluminum hydroxide did not provide any dose-sparing effects. Collectively, our results demonstrate that mmCT, CAF01, and CAF08b enhanced the protective humoral responses and had large dose-sparing effects on both Pn1-CRM197 and HA vaccines, although the adjuvant effect was clearly vaccine-dependent. The results support the potential use of safe adjuvants in situations when vaccine production capacity is limited, including vaccination of pediatric populations that may be of high risk.https://www.frontiersin.org/articles/10.3389/fimmu.2025.1646677/fullimmunizationneonatesadjuvantsdose-sparingantibodiesantibody-secreting cells
spellingShingle Jenny Lorena Molina Estupiñan
Jenny Lorena Molina Estupiñan
Poorya Foroutan Pajoohian
Poorya Foroutan Pajoohian
Gabriel Kristian Pedersen
Dennis Christensen
Serena Marchi
Emanuele Montomoli
Emanuele Montomoli
Stefanía P. Bjarnarson
Stefanía P. Bjarnarson
Ingileif Jonsdottir
Ingileif Jonsdottir
Audur Anna Aradottir Pind
Audur Anna Aradottir Pind
Dose-sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse model
Frontiers in Immunology
immunization
neonates
adjuvants
dose-sparing
antibodies
antibody-secreting cells
title Dose-sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse model
title_full Dose-sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse model
title_fullStr Dose-sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse model
title_full_unstemmed Dose-sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse model
title_short Dose-sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse model
title_sort dose sparing effects of novel adjuvants and aluminum hydroxide on two different vaccines in a neonatal mouse model
topic immunization
neonates
adjuvants
dose-sparing
antibodies
antibody-secreting cells
url https://www.frontiersin.org/articles/10.3389/fimmu.2025.1646677/full
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