Biology subjects

Fra-Bido, S.

Publications and source records attributed to Fra-Bido, S..

3 recordsLinked to original sources

bioRxiv2026

Antigen accumulation in the B cell follicle is impaired in aged mice

Vaccine responses are impaired in aged mice and older people. An essential early step in mounting successful responses to vaccines is the delivery of antigens from the site of injection to the draining lymph node. This study tested the hypothesis that particle drainage to the lymph node is impaired in older mice after intramuscular injection. We observed fewer 20nm nanoparticles in the B cell follicle of the draining lymph node in aged mice after intramuscular injection. However, there was no significant difference in the abundance of larger 1000nm particles in the lymph nodes of aged mice, which are typically transported to the lymph node by antigen presenting cells. This data suggests that access of smaller antigens to the B cell follicle is impaired in ageing and may have implications for the initiation of T and B cell responses after vaccination.

immunology↗

bioRxiv2020

A booster dose enhances immunogenicity of the COVID-19 vaccine candidate ChAdOx1 nCoV-19 in aged mice

The spread of SARS-CoV-2 has caused a global pandemic that has affected almost every aspect of human life. The development of an effective COVID-19 vaccine could limit the morbidity and mortality caused by infection, and may enable the relaxation of social distancing measures. Age is one of the most significant risk factors for poor health outcomes after SARS-CoV-2 infection, therefore it is desirable that any new vaccine candidates should elicit a robust immune response in older adults. Here, we test the immunogenicity of the adenoviral vectored vaccine ChAdOx1 nCoV-19 (AZD-1222) in aged mice. We find that a single dose of this vaccine induces cellular and humoral immunity in aged mice, but at a reduced magnitude than in younger adult mice. Furthermore, we report that a second dose enhances the immune response to this vaccine in aged mice, indicating that a primeboost strategy may be a rational approach to enhance immunogenicity in older persons.

immunology↗

bioRxiv2019

Follicular regulatory T cells can access the germinal centre independently of CXCR5

The germinal centre (GC) response is critical for generating high-affinity humoral immunity and immunological memory, which forms the basis of successful immunisation. Control of the GC response is thought to require follicular regulatory T (Tfr) cells, a subset of suppressive Foxp3+ Treg cells located within GCs. Relatively little is known about the exact role of Tfr cells within the GC, and the mechanism/s through which they exert their suppressive function. A unique feature of Tfr cells is their reported CXCR5-dependent localisation to the GC. Here we show that the lack of CXCR5 on Foxp3+ regulatory T cells resulted in a reduced frequency, but not an absence of, GC-localised Tfr cells. This demonstrates that additional, CXCR5-independent mechanisms facilitate Treg cell homing to the GC.

immunology↗