Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (645 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
Agents that cause agglutination of red blood cells. They include antibodies, blood group antigens, lectins, autoimmune factors, bacterial, viral, or parasitic blood agglutinins, etc.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Hemagglutinin; Exohemagglutinins; Isohemagglutinins.
Where it fits in the MeSH classification
- Broader topics
- Agglutinins
Research landscape
PubMed indexes 6,053 records tagged with the MeSH heading “Hemagglutinins” (counts retrieved 2026-10-29). 633 of them (10.5%) were published from 2020 onward, and the busiest period so far is through 1999 with 3,288 records.
Reviews account for 300 records (5.0%) and meta-analyses for 1. Randomized controlled trials number 77 (1.3%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 3,288 |
| 2000-2009 | 1,232 |
| 2010-2019 | 900 |
| 2020 onward | 633 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 300 | 5.0% |
| Meta-analyses | 1 | 0.0% |
| Randomized controlled trials | 77 | 1.3% |
Method: PubMed query "Hemagglutinins"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in pharmacology
Drug evidence builds in layers: laboratory pharmacology describes how a compound acts, pharmacokinetic studies describe how the body handles it, and randomized trials test whether it helps and what harms it causes. Post-marketing surveillance and observational studies reveal rarer adverse effects but cannot prove causation. This page is educational and is not a recommendation to start, stop or change any medicine; decisions about treatment belong with a qualified clinician.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| A recommended numbering scheme for influenza A HA subtypes | 2014 | Research article Design not recorded in structured metadata | 175 | cc by PMID 25391151 · DOI · PMC4229193 |
| Double-layered protein nanoparticles induce broad protection against divergent influenza A viruses | 2018 | Research article Design not recorded in structured metadata | 148 | cc by PMID 29367723 · DOI · PMC5783933 |
| Mechanisms of hemagglutinin targeted influenza virus neutralization | 2013 | Research article Design not recorded in structured metadata | 148 | cc by PMID 24348996 · DOI · PMC3862845 |
| Spatial transcriptomic mapping of early immune responses to an adjuvanted recombinant hemagglutinin vaccine | 2026 | Research article Design not recorded in structured metadata | 0 | cc by PMID 42568657 · DOI · PMC13447486 |
A recommended numbering scheme for influenza A HA subtypes [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Comparisons of residues between sub-types of influenza virus is increasingly used to assess the zoonotic potential of a circulating strain and for comparative studies across subtypes.
- Closing excerpt
- We provide a list of equivalences for amino acids which are known to affect the phenotype of the virus.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (148 words)
Comparisons of residues between sub-types of influenza virus is increasingly used to assess the zoonotic potential of a circulating strain and for comparative studies across subtypes. An analysis of N-terminal cleavage sites for thirteen subtypes of influenza A hemagglutinin (HA) sequences, has previously been described by Nobusawa and colleagues. We have expanded this analysis for the eighteen known subtypes of influenza. Due to differences in the length of HA, we have included strains from multiple clades of H1 and H5, as well as strains of H5 and H7 subtypes with both high and low pathogenicity. Analysis of known structures of influenza A HA enables us to define amino acids which are structurally and functionally equivalent across all HA subtypes using a numbering system based on the mature HA sequence. We provide a list of equivalences for amino acids which are known to affect the phenotype of the virus.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 25391151 · DOI · PMC4229193
Double-layered protein nanoparticles induce broad protection against divergent influenza A viruses [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Current influenza vaccines provide limited protection against circulating influenza A viruses.
- Closing excerpt
- These potent disassemblable protein nanoparticles indicate a wide application in protein drug delivery and controlled release.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (143 words)
Current influenza vaccines provide limited protection against circulating influenza A viruses. A universal influenza vaccine will eliminate the intrinsic limitations of the seasonal flu vaccines. Here we report methodology to generate double-layered protein nanoparticles as a universal influenza vaccine. Layered nanoparticles are fabricated by desolvating tetrameric M2e into protein nanoparticle cores and coating these cores by crosslinking headless HAs. Representative headless HAs of two HA phylogenetic groups are constructed and purified. Vaccinations with the resulting protein nanoparticles in mice induces robust long-lasting immunity, fully protecting the mice against challenges by divergent influenza A viruses of the same group or both groups. The results demonstrate the importance of incorporating both structure-stabilized HA stalk domains and M2e into a universal influenza vaccine to improve its protective potency and breadth. These potent disassemblable protein nanoparticles indicate a wide application in protein drug delivery and controlled release.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 29367723 · DOI · PMC5783933
Mechanisms of hemagglutinin targeted influenza virus neutralization [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Human monoclonal antibodies have been identified which neutralize broad spectra of influenza A or B viruses.
- Closing excerpt
- These insights into newly identified ways by which the human immune system can interfere with influenza virus infection may aid the development of novel universal vaccines and antivirals.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (111 words)
Human monoclonal antibodies have been identified which neutralize broad spectra of influenza A or B viruses. Here, we dissect the mechanisms by which such antibodies interfere with infectivity. We distinguish four mechanisms that link the conserved hemagglutinin (HA) epitopes of broadly neutralizing antibodies to critical processes in the viral life cycle. HA-stem binding antibodies can act intracellularly by blocking fusion between the viral and endosomal membranes and extracellularly by preventing the proteolytic activation of HA. HA-head binding antibodies prevent viral attachment and release. These insights into newly identified ways by which the human immune system can interfere with influenza virus infection may aid the development of novel universal vaccines and antivirals.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 24348996 · DOI · PMC3862845
Spatial transcriptomic mapping of early immune responses to an adjuvanted recombinant hemagglutinin vaccine [4]
Abstract reading summary — source excerpts
- Opening excerpt
- Vaccination relies on innate and adaptive responses initiated at the injection site followed by activation in draining lymph nodes.
- Closing excerpt
- Together, these data provide a previously unresolved view of what, when and where local inflammation and lymph node organization are spatially and temporally associated during early responses following vaccination with an adjuvanted rHA-protein vaccine.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (243 words)
Vaccination relies on innate and adaptive responses initiated at the injection site followed by activation in draining lymph nodes. However, high-plex, spatially resolved maps that couple injection site signals with transcriptomic programs in draining lymph nodes over time are still lacking. Here, we used spatial transcriptomics to map early responses to an adjuvanted recombinant haemagglutinin (rHA) protein vaccine formulated with Sanofi's proprietary oil-in-water adjuvant AF03. Mice received intramuscular rHA-protein or PBS. Injection site muscle and draining lymph nodes were collected at Days 1 and 7 post-prime for GeoMx™ Digital Spatial Profiling (DSP) and CosMx™ Spatial Molecular Imaging (SMI) single-cell imaging. In lymph nodes, rHA-protein vaccination induced early innate pathway activation in non-follicular regions at Day 1. By Day 7, adaptive pathways were enriched within follicles, with differentially expressed genes (DEGs) linked to germinal center (GC) formation, transcriptional regulation and signaling. These changes coincided with expansion of a proliferative GC-like B-cell cluster within the follicular area. At the injection site, 20x20 µM spatial grids were used rather than segmented cells. Clusters, enriched for fibroblast and muscle cells showed Day 1 induction of chemokines and interferon stimulated genes, concentrated in fibroblast rich stromal layers. These spatially organized tissue programs were accompanied by transient systemic cytokine elevations and increased antigen-specific IgG titers. Together, these data provide a previously unresolved view of what, when and where local inflammation and lymph node organization are spatially and temporally associated during early responses following vaccination with an adjuvanted rHA-protein vaccine.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42568657 · DOI · PMC13447486
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Oligosaccharide specificity of galectins: a search by frontal affinity chromatography [5]
- Research article History of lectins: from hemagglutinins to biological recognition molecules [6]
- Research article Intracellular functions of galectins [7]
- Research article Secretion of the galectin family of mammalian carbohydrate-binding proteins [8]
- Research article Galectinomics: finding themes in complexity [9]
- Research article Galectins: versatile modulators of cell adhesion, cell proliferation, and cell death [10]
References
- Burke DF, Smith DJ. A recommended numbering scheme for influenza A HA subtypes. . 2014. PMID 25391151 · DOI · PMC4229193
- Deng L, Mohan T, Chang TZ, Gonzalez GX, Wang Y, Kwon YM, et al.. Double-layered protein nanoparticles induce broad protection against divergent influenza A viruses. . 2018. PMID 29367723 · DOI · PMC5783933
- Brandenburg B, Koudstaal W, Goudsmit J, Klaren V, Tang C, Bujny MV, et al.. Mechanisms of hemagglutinin targeted influenza virus neutralization. . 2013. PMID 24348996 · DOI · PMC3862845
- Jackson L, Williams SM, Sinclair J, Kume A, Bahadoran A, Langohr IM, et al.. Spatial transcriptomic mapping of early immune responses to an adjuvanted recombinant hemagglutinin vaccine. . 2026. PMID 42568657 · DOI · PMC13447486
- Hirabayashi J, Hashidate T, Arata Y, Nishi N, Nakamura T, Hirashima M, et al.. Oligosaccharide specificity of galectins: a search by frontal affinity chromatography. Biochim Biophys Acta. 2002. PMID 12223272 · DOI
- Sharon N, Lis H. History of lectins: from hemagglutinins to biological recognition molecules. Glycobiology. 2004. PMID 15229195 · DOI
- Liu FT, Patterson RJ, Wang JL. Intracellular functions of galectins. Biochim Biophys Acta. 2002. PMID 12223274 · DOI
- Hughes RC. Secretion of the galectin family of mammalian carbohydrate-binding proteins. Biochim Biophys Acta. 1999. PMID 10580137 · DOI
- Cooper DN. Galectinomics: finding themes in complexity. Biochim Biophys Acta. 2002. PMID 12223271 · DOI
- Perillo NL, Marcus ME, Baum LG. Galectins: versatile modulators of cell adhesion, cell proliferation, and cell death. J Mol Med (Berl). 1998. PMID 9625297 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.