Molecular divergence and convergence of mammalian antibody responses to the influenza virus hemagglutinin stem

H Huibin Lv Q Qi Wen Teo T Tossapol Pholcharee W Wenkan Liu (Department of Biochemistry, University of Illinois Urbana-Champaign) S Sawrab Roy (Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri) L Lei Shi (School of Health Management Guangzhou Medical University Guangzhou China) A Akshita B. Gopal (Department of Biochemistry, University of Illinois Urbana-Champaign) M Madison R. Ardagh (Department of Biochemistry, University of Illinois Urbana-Champaign) C Chunke Chen (The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong) Y Yuanxin Sun (The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong) Y Yang Wei Huan (Department of Biochemistry, University of Illinois Urbana-Champaign) W Walter N. Harrington (Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital) A Arjun Mehta (Department of Biochemistry, University of Illinois Urbana-Champaign) M Mateusz Szlembarski (Department of Biochemistry, University of Illinois Urbana-Champaign) D Danbi Choi (Department of Biochemistry, University of Illinois Urbana-Champaign) Q Qihong Gao (The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong) F Fiona S. L. Fung (The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong) F Fangxiu Xu (Roy J. Carver Biotechnology Center, University of Illinois Urbana-Champaign) R Richard J. Webby C Chris K. P. Mok (The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong) W Wenjun Ma (Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri) N Nicholas C. Wu

Abstract

Antibody responses to the influenza virus hemagglutinin (HA) stem, a major target for broadly protective vaccine development, have been extensively characterized in humans. However, they remain largely elusive in other natural influenza hosts, including pigs, which are considered intermediate hosts for the emergence of pandemic strains. By leveraging single-cell variable, diversity, and joining (VDJ) sequencing, this study identified 25 porcine antibodies to the HA stem, including two cross-group bnAbs, 14-8 and 15-1, from vaccinated specific-pathogen-free pigs and unvaccinated domestic pigs. Cryogenic electron microscopy analysis showed that 14-8 targeted the well-characterized central stem epitope, whereas 15-1 bound to a linear epitope spanning the HA1/HA2 junction. Additionally, while some porcine and human bnAbs targeted the central stem epitope via convergent molecular signatures, our results revealed a pig-specific recurring binding motif. Overall, our findings provide important insights into the commonalities and uniqueness of antibody responses between different species, which have significant implications for vaccine development for nonhuman animals.

Article Details

Volume / Issue Vol. 122, Issue 40
Published October 07, 2025
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (22)

H

Huibin Lv

Q

Qi Wen Teo

T

Tossapol Pholcharee

W

Wenkan Liu

Department of Biochemistry, University of Illinois Urbana-Champaign

S

Sawrab Roy

Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri

L

Lei Shi

School of Health Management Guangzhou Medical University Guangzhou China

A

Akshita B. Gopal

Department of Biochemistry, University of Illinois Urbana-Champaign

M

Madison R. Ardagh

Department of Biochemistry, University of Illinois Urbana-Champaign

C

Chunke Chen

The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong

Y

Yuanxin Sun

The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong

Y

Yang Wei Huan

Department of Biochemistry, University of Illinois Urbana-Champaign

W

Walter N. Harrington

Department of Host-Microbe Interactions, St. Jude Children’s Research Hospital

A

Arjun Mehta

Department of Biochemistry, University of Illinois Urbana-Champaign

M

Mateusz Szlembarski

Department of Biochemistry, University of Illinois Urbana-Champaign

D

Danbi Choi

Department of Biochemistry, University of Illinois Urbana-Champaign

Q

Qihong Gao

The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong

F

Fiona S. L. Fung

The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong

F

Fangxiu Xu

Roy J. Carver Biotechnology Center, University of Illinois Urbana-Champaign

R

Richard J. Webby

C

Chris K. P. Mok

The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong

W

Wenjun Ma

Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri

N

Nicholas C. Wu