GO:0070947 neutrophil-mediated killing of fungus: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0070947 describes the directed killing of a fungal cell by a neutrophil, a key innate immune process against fungal pathogens.
• Neutrophils kill fungi through phagocytosis, degranulation, reactive oxygen species (ROS) production, and neutrophil extracellular trap (NET) formation.
• Fungal pathogens can evade neutrophil killing by modifying surface antigens, secreting proteases, or subverting NETs.
• Key genes involved include CYBB, NCF1, NCF2, MPO, ELANE, and ITGAM, which are critical for oxidative burst and degranulation.
• Defects in neutrophil-mediated killing of fungus lead to invasive fungal infections, especially in immunocompromised patients.
• CRISPR knockout, knock-in, and overexpression models enable functional dissection of genes in this process.
Description
Neutrophils are the most abundant circulating leukocytes and serve as first responders against fungal pathogens. The Gene Ontology (GO) term GO:0070947, neutrophil-mediated killing of fungus, captures the directed killing of a fungal cell by a neutrophil. This process is essential for host defense against opportunistic fungi such as Candida albicans and Aspergillus fumigatus, and its dysregulation contributes to invasive fungal diseases. Understanding the molecular mechanisms of neutrophil-mediated fungal killing is critical for developing immunotherapies and vaccines. Recent studies have elucidated how neutrophils recognize, engulf, and destroy fungal cells through oxidative and non-oxidative pathways. Moreover, fungal pathogens have evolved evasion strategies, including capsule modification and NET subversion, highlighting the dynamic arms race between host and pathogen. This article synthesizes current knowledge on the mechanisms, key genes, and research methods for studying GO:0070947, providing a resource for immunologists and infectious disease researchers.
neutrophil-mediated killing of fungus At A Glance
| GO ID | GO:0070947 |
|---|---|
| GO term | neutrophil-mediated killing of fungus |
| Ontology | biological_process |
| Synonym | neutrophil mediated killing of fungus |
| Definition | The directed killing of a fungal cell by a neutrophil. |
| Major function | Innate immune defense against fungal pathogens |
| Related processes | Phagocytosis, degranulation, ROS production, NET formation |
| Taxonomic range | Animals, particularly mammals |
What Is GO:0070947?
GO:0070947 is defined as the biological process in which a neutrophil directly kills a fungal cell. This encompasses all neutrophil effector functions that lead to fungal cell death, including phagocytosis, degranulation, reactive oxygen species (ROS) production, and the release of neutrophil extracellular traps (NETs). The term is specific to neutrophils as the effector cell and fungi as the target, distinguishing it from other antimicrobial processes.
Why Is neutrophil-mediated killing of fungus Important in Cell Biology?
Neutrophil-mediated killing of fungus is a cornerstone of innate immunity against fungal infections. Invasive fungal diseases cause significant morbidity and mortality in immunocompromised individuals, and neutrophils are essential for controlling fungal burden. Understanding this process at the molecular level can reveal therapeutic targets for enhancing fungal clearance, especially in patients with neutropenia or neutrophil dysfunction. Furthermore, fungal pathogens continuously evolve evasion mechanisms, making it crucial to study host-pathogen interactions to develop novel antifungal strategies.
• Critical for defense against opportunistic fungal pathogens like Candida and Aspergillus.
• Neutropenia or neutrophil defects predispose to invasive fungal infections.
• Fungal evasion mechanisms, such as capsule modification, can subvert neutrophil killing.
• NETs are a key antifungal mechanism, but some fungi can degrade or evade them.
• ROS production by NADPH oxidase is essential for fungal killing.
• Defects in oxidative burst (e.g., chronic granulomatous disease) increase fungal susceptibility.
• Understanding this process aids vaccine development and immunotherapy.
• CRISPR screens can identify host genes required for fungal killing.
• Modeling neutrophil-fungus interactions informs treatment of drug-resistant infections.
• Comparative studies across fungal species reveal conserved and specific killing mechanisms.
What Happens During neutrophil-mediated killing of fungus?
Recognition and Chemotaxis
In simple terms: Neutrophils sense chemical signals from fungi and move toward them.
Neutrophils are recruited to sites of fungal infection by chemokines and complement components. They recognize fungal cell wall components such as beta-glucan and mannan through pattern recognition receptors including Dectin-1 and TLRs. This recognition triggers intracellular signaling that leads to neutrophil activation and directed migration toward the fungus.
Phagocytosis and Degranulation
In simple terms: Neutrophils engulf fungi and release toxic granules to kill them.
Upon contact, neutrophils phagocytose fungal cells, forming a phagosome. Granules containing antimicrobial peptides (e.g., defensins, cathelicidins) and proteases (e.g., elastase) fuse with the phagosome, releasing their contents to degrade the fungus. This process is enhanced by opsonization with antibodies or complement.
Oxidative Burst
In simple terms: Neutrophils produce reactive oxygen species to poison fungi.
The NADPH oxidase complex (CYBB, NCF1, NCF2, NCF4, RAC1/2) assembles on the phagosome membrane and generates superoxide, which is converted to hydrogen peroxide and other reactive oxygen species (ROS). ROS damage fungal DNA, proteins, and lipids, leading to cell death. Myeloperoxidase (MPO) further converts hydrogen peroxide to hypochlorous acid, enhancing killing.
Neutrophil Extracellular Trap (NET) Formation
In simple terms: Neutrophils can throw out DNA webs that trap and kill fungi.
Activated neutrophils can release NETs, which are web-like structures of DNA, histones, and antimicrobial proteins. NETs physically trap fungal cells and expose them to high local concentrations of antimicrobial agents, including calprotectin and elastase. Some fungi, such as Providencia rettgeri, can evade NETs by degrading them.
Fungal Evasion and Resistance
In simple terms: Fungi have ways to avoid being killed by neutrophils.
Fungal pathogens employ various strategies to evade neutrophil killing. For example, Staphylococcus aureus (though bacterial) modifies its capsule to resist phagocytosis, and Candida albicans can mask beta-glucan to avoid recognition. Pythium insidiosum antigens can enhance neutrophil killing, suggesting that some fungi are more susceptible. Understanding these evasion mechanisms is crucial for developing effective therapies.
Key Genes Involved in GO:0070947 neutrophil-mediated killing of fungus
The following genes and proteins are central to neutrophil-mediated killing of fungi, based on their roles in recognition, oxidative burst, degranulation, and NET formation.
| Gene | Major Role | Research Relevance |
|---|---|---|
| CYBB | NADPH oxidase subunit; ROS production | Mutations cause chronic granulomatous disease with fungal susceptibility |
| NCF1 | NADPH oxidase subunit; ROS production | Defects impair fungal killing |
| NCF2 | NADPH oxidase subunit; ROS production | Defects impair fungal killing |
| NCF4 | NADPH oxidase subunit; ROS production | Regulates oxidase assembly |
| MPO | Myeloperoxidase; produces hypochlorous acid | Enhances oxidative killing of fungi |
| ELANE | Neutrophil elastase; degrades fungal proteins | Important for degranulation and NET formation |
| ITGAM | Integrin alpha-M; adhesion and phagocytosis | Defects cause leukocyte adhesion deficiency |
| ITGB2 | Integrin beta-2; adhesion and phagocytosis | Defects cause leukocyte adhesion deficiency |
| FCGR1A | Fc gamma receptor; antibody-dependent phagocytosis | Mediates opsonin-dependent killing |
| FCGR2A | Fc gamma receptor; antibody-dependent phagocytosis | Mediates opsonin-dependent killing |
| CLEC7A | Dectin-1; recognizes beta-glucan | Critical for fungal recognition |
| TLR2 | Toll-like receptor 2; recognizes fungal components | Initiates inflammatory signaling |
| TLR4 | Toll-like receptor 4; recognizes fungal components | Initiates inflammatory signaling |
| CARD9 | Adaptor protein downstream of Dectin-1 | Defects increase fungal susceptibility |
| RAC1 | Rho GTPase; NADPH oxidase assembly | Regulates ROS production |
| RAC2 | Rho GTPase; NADPH oxidase assembly | Regulates ROS production |
| PADI4 | Peptidylarginine deiminase 4; histone citrullination | Required for NET formation |
| GSDMD | Gasdermin D; pore formation in NETosis | Mediates NET release |
How Is neutrophil-mediated killing of fungus Regulated?
Neutrophil-mediated killing of fungus is tightly regulated by intracellular signaling pathways. Activation of protein kinase C (PKC) and phosphatidylinositol 3-kinase (PI3K) downstream of pattern recognition receptors promotes NADPH oxidase assembly and degranulation. Cytokines such as GM-CSF and TNF-alpha prime neutrophils for enhanced fungal killing. Conversely, regulatory pathways involving SHP-1 and SOCS proteins dampen neutrophil responses to prevent tissue damage. Fungal pathogens can also modulate host signaling; for instance, Staphylococcus aureus secretes leukocidins and nuclease to prevent neutrophil-mediated killing. Understanding these regulatory mechanisms is essential for therapeutic manipulation.
neutrophil-mediated killing of fungus and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| CYBB | Chronic granulomatous disease; impaired fungal killing | Knockout mouse or iPSC-derived neutrophils |
| NCF1 | Chronic granulomatous disease | Knockout mouse |
| MPO | Increased susceptibility to Candida | Knockout mouse |
| ELANE | Neutropenia and impaired killing | Knockout mouse |
| CLEC7A | Dectin-1 deficiency; fungal susceptibility | Knockout mouse |
Invasive Fungal Infections
Defects in neutrophil-mediated killing of fungus lead to invasive fungal infections, particularly in patients with neutropenia, chronic granulomatous disease (CGD), or leukocyte adhesion deficiency. CGD patients, who lack functional NADPH oxidase, are highly susceptible to Aspergillus and Candida infections. Similarly, impaired NET formation has been linked to increased fungal dissemination.
Chronic Granulomatous Disease (CGD)
CGD is caused by mutations in CYBB, NCF1, NCF2, or NCF4, resulting in defective ROS production. Neutrophils from CGD patients fail to kill fungi effectively, leading to recurrent bacterial and fungal infections. This highlights the critical role of oxidative burst in GO:0070947.
Fungal Evasion and Drug Resistance
Fungal pathogens such as Candida auris and Aspergillus fumigatus have developed resistance to antifungals and evasion of neutrophil killing. For example, Pythium insidiosum antigens can enhance neutrophil killing, suggesting potential immunotherapeutic targets. Understanding evasion mechanisms, such as capsule modification in Cryptococcus neoformans, is vital for new treatments.
From neutrophil-mediated killing of fungus-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does CYBB knockout impair fungal killing? | CRISPR knockout in HL-60 or PLB-985 cells |
| Does a point mutation in NCF1 affect ROS production? | CRISPR point mutation knock-in in neutrophil-like cells |
| Can overexpression of MPO enhance fungal killing? | CRISPR overexpression in primary neutrophils |
| What genes are essential for NET formation? | CRISPR library screening in neutrophil-like cells |
| How does fungal antigen affect neutrophil activation? | Co-culture with Pythium insidiosum antigens |
| Does antibody opsonization improve killing? | Antibody-dependent killing assay |
How to Study the neutrophil-mediated killing of fungus Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CFU killing assay | Fungal survival after neutrophil challenge | Assessing neutrophil fungicidal activity |
| ROS detection (DHR 123) | Reactive oxygen species production | Evaluating oxidative burst |
| NET quantification (Sytox Green) | Extracellular DNA release | Measuring NET formation |
| Phagocytosis assay (flow cytometry) | Internalization of fungi | Assessing engulfment |
| CRISPR knockout screen | Gene essentiality for fungal killing | Identifying host factors |
| RNA-seq | Transcriptional changes during infection | Discovering regulated pathways |
| Proteomics | Protein expression and modifications | Identifying effector proteins |
In Vitro Killing Assays
The gold standard for measuring neutrophil-mediated killing of fungus is the in vitro killing assay, where neutrophils are co-incubated with fungal cells (e.g., Candida albicans, Aspergillus fumigatus) at a defined multiplicity of infection. Fungal survival is quantified by colony-forming unit (CFU) plating or by fluorescent viability dyes. This method directly assesses the functional outcome of GO:0070947.
ROS Detection
Reactive oxygen species production can be measured using chemiluminescence, flow cytometry with DHR 123 or DCFDA, or electron spin resonance. These methods quantify the oxidative burst, a key component of neutrophil-mediated fungal killing.
NET Visualization and Quantification
Neutrophil extracellular traps can be visualized by immunofluorescence for DNA-histone complexes (e.g., H3Cit) and myeloperoxidase. Quantification is done by microscopy or by measuring extracellular DNA with Sytox Green. This method is essential for studying NET-mediated fungal killing.
CRISPR Screening
Genome-wide CRISPR knockout screens in neutrophil-like cell lines (e.g., HL-60) can identify host genes required for fungal killing. Cells are transduced with a lentiviral sgRNA library, selected, and challenged with fungi; sgRNAs enriched in surviving cells indicate genes that are dispensable for killing, while depleted sgRNAs indicate essential genes.
How CRISPR Can Be Used to Study GO:0070947 neutrophil-mediated killing of fungus
Knockout
CRISPR knockout of candidate genes (e.g., CYBB, NCF1) in neutrophil-like cell lines or primary neutrophils can definitively test their requirement for fungal killing. For example, knocking out CYBB abolishes ROS production and impairs killing of Candida albicans. EDITGENE provides validated knockout cell models for such studies.
Point Mutation
Point mutations can model human polymorphisms or disease-causing variants. For instance, introducing the NCF1 p.Arg90His mutation into cells can recapitulate the functional defect seen in chronic granulomatous disease. CRISPR point mutation knock-in allows precise modeling of such variants.
Knock-in
Knock-in of reporter tags (e.g., GFP, HA) into endogenous loci enables real-time tracking of protein localization and dynamics during fungal killing. For example, tagging MPO with GFP allows visualization of granule trafficking. EDITGENE offers tagged knock-in services for such applications.
Overexpression
Overexpression of antimicrobial proteins (e.g., MPO, ELANE) or signaling molecules (e.g., RAC2) can enhance neutrophil killing of fungi. This approach can identify gain-of-function strategies for immunotherapy. CRISPR activation (CRISPRa) or cDNA overexpression models are suitable.
How EDITGENE Supports neutrophil-mediated killing of fungus Research
Researchers studying neutrophil-mediated killing of fungus-related genes often need to determine whether a candidate gene is causally involved in fungal clearance or is merely a bystander. This requires precise genetic manipulation in relevant cell models, such as neutrophil-like cell lines or primary neutrophils. EDITGENE provides a comprehensive suite of CRISPR services to enable such functional studies, from knockout to knock-in and overexpression, along with library screening and bioinformatics support.
Contact EDITGENE today to design your custom CRISPR model for neutrophil-mediated killing of fungus research.
Frequently Asked Questions About neutrophil-mediated killing of fungus
What is GO:0070947?
GO:0070947 is the Gene Ontology term for neutrophil-mediated killing of fungus, the biological process in which a neutrophil directly kills a fungal cell.
What genes are involved in neutrophil-mediated killing of fungus?
Key genes include CYBB, NCF1, NCF2, MPO, ELANE, ITGAM, and CLEC7A, which are involved in recognition, oxidative burst, and degranulation.
How do neutrophils kill fungi?
Neutrophils kill fungi through phagocytosis, degranulation, reactive oxygen species production, and neutrophil extracellular trap formation.
What diseases are associated with defective neutrophil-mediated fungal killing?
Defects lead to invasive fungal infections, chronic granulomatous disease, and increased susceptibility to Candida and Aspergillus.
Can fungi evade neutrophil killing?
Yes, fungi such as Candida albicans and Cryptococcus neoformans can evade killing by masking antigens, modifying capsules, or degrading NETs.
What methods are used to study neutrophil-mediated killing of fungus?
Common methods include in vitro killing assays, ROS detection, NET quantification, phagocytosis assays, and CRISPR screens.
What is the role of NADPH oxidase in fungal killing?
NADPH oxidase produces superoxide and other reactive oxygen species that are toxic to fungi; defects in this complex cause chronic granulomatous disease.
How can CRISPR help study neutrophil-mediated killing of fungus?
CRISPR knockout, knock-in, and overexpression models allow functional testing of candidate genes in neutrophil-like cells, identifying essential host factors.
What are neutrophil extracellular traps (NETs)?
NETs are web-like structures of DNA and antimicrobial proteins released by neutrophils to trap and kill fungi.
Why is neutrophil-mediated killing of fungus important for immunocompromised patients?
Immunocompromised patients often lack functional neutrophils, making them highly susceptible to invasive fungal infections; understanding this process can guide therapies.
Conclusion
Neutrophil-mediated killing of fungus (GO:0070947) is a vital innate immune process that protects against fungal pathogens. It involves coordinated recognition, phagocytosis, oxidative burst, and NET formation, with key roles for genes such as CYBB, NCF1, and MPO. Defects in this process lead to severe fungal infections, highlighting its clinical importance. Advances in CRISPR technology now enable precise genetic dissection of this process, offering new avenues for therapeutic intervention. EDITGENE provides comprehensive CRISPR services to support research in this field, from knockout to overexpression and screening.
References
- 1. Long MB et al.. 2024. A Bispecific Monoclonal Antibody Targeting Psl and PcrV Enhances Neutrophil-Mediated Killing of Pseudomonas aeruginosa in Patients with Bronchiectasis.. Am J Respir Crit Care Med 210(1):35-46 PMID: 38754132
- 2. de Jong NWM et al.. 2019. Immune Evasion by Staphylococcus aureus.. Microbiol Spectr 7(2) PMID: 30927347
- 3. Medhasi S et al.. 2025. Pythium insidiosum-antigen enhances neutrophil-mediated killing of zoospores.. Sci Rep 15(1):5210 PMID: 39939657
- 4. van Kessel KP et al.. 2014. Neutrophil-Mediated Phagocytosis of Staphylococcus aureus.. Front Immunol 5:467 PMID: 25309547
- 5. Castro JE et al.. 2025. Clinical isolates of Providencia rettgeri and Providencia Stuartii evades neutrophil-mediated killing by subverting neutrophil-extracellular traps.. Front Immunol 16:1636387 PMID: 41112272
- 6. Walker LL et al.. 2026. NeuO-mediated O-acetylation of uropathogenic Escherichia coli K1 capsule enhances resistance to phage and neutrophil killing.. J Bacteriol 208(3):e0061025 PMID: 41665341
- 7. Bhattacharya M et al.. 2020. Leukocidins and the Nuclease Nuc Prevent Neutrophil-Mediated Killing of Staphylococcus aureus Biofilms.. Infect Immun 88(10) PMID: 32719153
