Doctoral Defence in Health and Medical Sciences – Jenny Lorena Molina Estupiñan

On Monday, 19 October, Jenny Lorena Molina Estupiñan will defend her doctoral thesis in Health and Medical Sciences at the Faculty of Medicine, University of Iceland. The title of her thesis is: Enhancing neonatal immune responses with different vaccination strategies: Novel adjuvants and mucosal immunization.

The opponents are Dr Ed C. Lavelle, Professor at Trinity College Dublin, Ireland, and Dr Sören E. Degn, Associate Professor at the Department of Biomedicine, Aarhus University, Denmark.

The principal supervisor was Ingileif Jónsdóttir, Professor Emerita, and the supervisor was Stefanía P. Bjarnarson, Associate Professor. Other members of the doctoral committee were Jóna Freysdóttir, Professor, and Þórunn Ásta Ólafsdóttir, Associate Professor.

Sædís Sævarsdóttir, Professor and Dean of the Faculty of Medicine, will preside over the ceremony, which will take place in the University of Iceland’s Aula and begin at 1:00 p.m.

Abstract

Vaccination is one of the most effective tools for preventing infectious diseases. Infants remain particularly vulnerable to severe infections during the first months of life, when routine childhood vaccinations may not yet provide sufficient protection. Vaccinating soon after birth could help shorten this vulnerable period, but neonatal vaccination is challenging because their poorly developed immune system responds differently from that of older children and adults, often resulting in weaker and shorter-lived antibody responses.

In this project, the effects of immunization route and novel adjuvants on neonatal immune responses were investigated. Using a neonatal mouse model, the effects of intranasal and subcutaneous immunization on the development, activation of B cells and long-term survival of antibody-producing B cells were compared. The vaccine dose-sparing capacity of different adjuvants was also evaluated. The studies focused on responses to vaccines against Streptococcus pneumoniae and influenza.

The results demonstrate that the route of vaccination strongly influences the timing and quality of neonatal immune responses. Intranasal vaccination promoted earlier B cell activation and plasma cell differentiation and accelerated the establishment of supportive survival environments in the bone marrow. This was associated with sustained systemic IgG antibody responses as well as persistent mucosal IgA responses, highlighting the potential of mucosal vaccination to provide protection at respiratory sites of infection.

The results also demonstrated substantial vaccine dose-sparing effects of several novel adjuvants, still maintaining protective antibody responses against pneumococcal and influenza vaccines.

Together, these results show that combining appropriate immunization routes with effective adjuvants can overcome important limitations of neonatal immunity and provide new evidence that may contribute to the development of more effective vaccination strategies for the youngest population.

About the doctoral candidate

Jenny Molina Estupiñán was born in Valencia, Venezuela, in 1988. She completed a BSc degree in Biology at the University of Carabobo in Venezuela in 2009. She then pursued further studies in Spain, where she completed a master’s degree in Tropical Parasitic Diseases at the University of Valencia in 2013 and a master’s degree in Molecular and Cellular Biology at the Autonomous University of Madrid in 2014.

Jenny began her doctoral studies at the University of Iceland in 2019. Her doctoral research has focused on strategies to enhance immune responses to vaccination early in life, with particular emphasis on novel adjuvants and mucosal immunization. Her research has contributed to a better understanding of how different vaccination strategies can enhance immune responses during the early stages of life.

Alongside her doctoral studies, Jenny has actively participated in teaching immunology at the University of Iceland, as well as in the training and supervision of students, thereby contributing to both research and the education of the next generation of scientists.

Jenny’s parents are Julio Molina and María Rosa Estupiñan, and her son is Daniel Gunnar, born in 2022.