Skip to main content

#Sialic Acid #Receptors in #Human Mammary Tissue: Implications for #Infection with Novel #Influenza Strains

Image
By G.M.

 


Abstract

Importance: 

Highly pathogenic avian influenza (HPAI) A H5N1 has been recognized for nearly three decades as a threat to avian species and as a virus with pandemic potential if spillover into human populations occurs. Recently the virus has evolved capacity to infect many mammalian species, including dairy cattle, increasing the risk for human exposure and the pandemic threat. Sialic acids (SA) serve as binding sites for influenza viruses. The distribution of SA determines infectivity of specific influenza viruses across species and tissue tropism. Hemagglutinin (HA) of human and swine adapted influenza viruses bind primarily to SA with α2,6-galactose linkages and avian influenza viruses preferentially bind to SA with α2,3-galactose linkages. Recently, the bovine udder was found to contain SA with α2,3 linkages which allow the H5N1 virus to bind to bovine udder epithelium and to infect milk. The distribution of SA receptors in the human mammary gland is unknown. 

Objective: 

Evaluate normal human mammary tissue for the presence of both human and avian SA receptors. 

Design: 

Retrospective evaluation of lectin binding to sialic acids in human mammary tissue. 

Setting: 

US academic health center. 

Participants: 

Specimens obtained from de-identified women with residual non-malignant tissue following breast surgery at the University of California, San Diego. 

Exposures: 

Lectin affinity-staining of human tissue for the presence of SA. 

Main Outcomes and Measures: 

Presence or absence of lectin staining. 

Results: 

All mammary tissue samples demonstrated lectin staining for both SA receptors with α2,6-galactose and α2,3-galactose linkages. 

Conclusions and Relevance: 

The presence of SA receptors that can bind HPAI A H5N1 in human mammary tissue indicates that human milk could be infected during severe avian influenza infection. Pandemic preparedness must prioritize mechanisms to protect the safety of human milk.


Competing Interest Statement

Dr. Byington has intellectual property in and receives royalties from BioFire (biomerieux) through the University of Utah. Dr. Byington is a member of the board of directors of Becton Dickinson.

Funding Statement

This study did not receive any funding

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.08.06.25333154v1

____

Labels:

Comments

Post a Comment

Popular posts from this blog

#Neuroinvasive #Oropouche virus in a patient with #HIV from extra-Amazonian #Brazil

By G.M.
{Excerpt} A novel reassortant Oropouche virus (OROV) lineage (with medium [M], large [L], and small [S] RNA segments : M1L2S2) has driven Brazil's largest and most geographically widespread OROV epidemic , expanding beyond the endemic Amazon basin to establish local transmission across multiple Brazilian states and other previously unaffected Latin American countries . The rapid spread of this lineage underscores its evolutionary potential and reinforces its significance as a public health threat .1 Similar to chikungunya and Zika viruses, expanding arboviruses can exhibit unexpected clinical and epidemiological shifts , including vertical transmissions , neuroinvasive effects, and potentially fatal outcomes.2–4 Although OROV typically causes self-limited febrile illness, accumulating clinical and experimental evidence suggests neurotropic potential .5 This Correspondence describes the first confirmed case of neuroinvasive OROV infection caused by the emergent M1L2S2 lineage in ext...
Post a Comment
Read more »

No evidence of immune #exhaustion after repeated #SARS-CoV-2 #vaccination in vulnerable and healthy populations

By G.M.
Abstract Frequent SARS-CoV-2 vaccination in vulnerable populations has raised concerns that this may contribute to T cell exhaustion , which could negatively affect the quality of immune protection. Herein, we examined the impact of repeated SARS-CoV-2 vaccination on T cell phenotypic and functional exhaustion in frail older adults in long-term care (n = 23), individuals on immunosuppressive drugs (n = 10), and healthy adults (n = 43), in Canada . Spike-specific CD4+ and CD8+ T cell levels did not decline in any cohort following repeated SARS-CoV-2 vaccination, nor did the expression of exhaustion markers on spike-specific or total T cells increase. T cell production of multiple cytokines (i.e. polyfunctionality) in response to the spike protein of SARS-CoV-2 did not decline in any cohort following repeated vaccination. None of the cohorts displayed elevated levels of terminally differentiated T cells following multiple SARS-CoV-2 vaccinations. Thus, repeated SARS-CoV-2 vaccination was...
Post a Comment
Read more »

Chimeric #hemagglutinin and #M2 #mRNA #vaccine for broad #influenza subtype protection

By G.M.
Abstract Since multiple and unpredicted influenza viruses cause seasonal epidemics and even high-risk pandemics , developing a universal influenza vaccine is essential to provide broad protection against various influenza subtypes. Combined with the mRNA lipid nanoparticle-encapsulated (mRNA-LNP) vaccine platform and chimeric immunogen strategy , we developed a novel cocktail mRNA vaccine encoding chimeric HAs (cH5/1-BV, cH7/3) and intact M2 (termed Fluaxe), which confers broad protection against major circulating IAVs and IBVs , as well as highly pathogenic avian influenza . Two-dose intramuscular immunization of Fluaxe in mice elicited cross-reactive neutralizing antibodies , T cell responses, and long-lived immunity, resulting in robust protection against multiple lethal influenza virus infections and severe acute lung injuries . In particular, intramuscular administration stimulated systemic immunity together with a prominent lung tropism of memory cells . Moreover, Fluaxe immuniza...
Post a Comment
Read more »