GO:0031640 killing of cells of another organism: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031640 describes the active killing of one organism's cells by another organism, distinct from cell-autonomous death.
• Key effectors include NK cells, cytotoxic T lymphocytes, and antimicrobial contact surfaces that directly induce target cell death [1, 4, 6, 7].
• The process is central to immunity against intracellular pathogens such as Mycobacterium tuberculosis and to autoimmune beta-cell destruction in diabetes [6, 7].
• Experimental models range from co-culture killing assays and intravital imaging to metallic copper surface exposure and yeast community competition [4, 5, 7].
• CRISPR knockout, knock-in, and overexpression models enable causal dissection of genes mediating contact-dependent killing [1, 6].
• Understanding GO:0031640 informs immunotherapy, antimicrobial surface design, and autoimmune disease research [1, 4, 7].
Description
The Gene Ontology term GO:0031640, killing of cells of another organism, defines any process in which one organism induces the death of cells belonging to a different organism. This biological process is fundamental to host defense, microbial competition, and therapeutic strategies that exploit cell-mediated cytotoxicity [1, 6]. Unlike programmed cell death that arises from internal signals, killing of cells of another organism requires direct or indirect action by an external organism, often through contact-dependent mechanisms or secreted effectors [4, 5]. Researchers study this term to understand immune surveillance, pathogen clearance, and the molecular arms race between species [1, 6, 7]. The process is experimentally tractable using co-culture systems, genetic knockouts, and advanced imaging, making it a rich area for CRISPR-based functional genomics [1, 7].
killing of cells of another organism At A Glance
| GO ID | GO:0031640 |
|---|---|
| GO term | killing of cells of another organism |
| Ontology | biological_process |
| Synonym | killing of cells of other organism |
| Definition | Any process in an organism that results in the killing of cells of another organism, including in some cases the death of the other organism. |
| Major function | Induction of target cell death by an external organism, often through contact-dependent or secreted effectors. |
| Related processes | Immune cytotoxicity, antimicrobial surface killing, microbial competition, autoimmune beta-cell destruction. |
| Key cell types | Natural killer cells, cytotoxic T lymphocytes, neutrophils, yeast killer cells. |
| Experimental readouts | Co-culture killing assays, intravital imaging, colony-forming unit assays, flow cytometry. |
What Is GO:0031640?
GO:0031640 encompasses any process in an organism that results in the killing of cells of another organism, including in some cases the death of the other organism. Killing here refers to the induction of death in one cell by another cell, not cell-autonomous death due to internal or other environmental conditions. This definition excludes apoptosis triggered by intracellular stress unless it is initiated by an external organism. The term captures phenomena such as natural killer cell-mediated cytotoxicity, cytotoxic T lymphocyte killing, contact-mediated killing on antimicrobial surfaces, and microbial competition systems [1, 4, 5, 6, 7].
Why Is killing of cells of another organism Important in Cell Biology?
GO:0031640 is critical for understanding how organisms defend against pathogens, how immune cells eliminate infected or malignant cells, and how microbial communities compete [1, 6]. Defects in killing mechanisms can lead to chronic infections, while excessive killing contributes to autoimmune diseases such as type 1 diabetes [6, 7]. The term also guides the design of antimicrobial surfaces and immunotherapies that harness cell-mediated killing. Because the process is genetically encoded, CRISPR screens and knockout models are essential to identify the genes that execute or regulate killing [1, 6].
• Host defense against intracellular pathogens like Mycobacterium tuberculosis relies on NK cell-mediated killing.
• Cytotoxic T lymphocytes kill pancreatic islet cells in autoimmune diabetes, a process visualized by intravital imaging.
• Natural killer cells provide antitumor activity by directly killing malignant cells.
• Contact-mediated killing on dry metallic copper surfaces informs antimicrobial material design.
• Yeast communities use autotoxin-mediated latecomer killing to compete for resources.
• Neutrophil bactericidal activity is regulated by circadian clocks, linking killing to daily rhythms.
• Selective killing of cancer cells by synthetic compounds like TPEN variants offers therapeutic leads.
• Understanding killing mechanisms can improve vaccine design and immunotherapy [1, 6].
• CRISPR knockout of killing effectors enables causal gene discovery [1, 6].
• Dysregulated killing underlies tissue destruction in autoimmune diseases.
What Happens During killing of cells of another organism?
Recognition and target engagement
In simple terms: The killer cell first finds and attaches to its target.
Killing of cells of another organism typically begins with recognition of target cells by effector cells such as natural killer cells or cytotoxic T lymphocytes [1, 7]. This step involves receptor-ligand interactions that ensure specificity and prevent bystander damage. In contact-mediated killing on metallic copper surfaces, physical contact between yeast cells and the dry copper surface triggers lethal damage. In yeast communities, latecomer cells are killed by autotoxins produced by earlier colonizers, demonstrating recognition through diffusible factors.
Effector delivery or contact-dependent damage
In simple terms: The killer delivers a lethal hit, either by direct contact or by releasing toxic molecules.
After engagement, effectors deliver killing signals. Human natural killer cells mediate killing of intracellular Mycobacterium tuberculosis via granule-independent mechanisms, indicating that soluble factors or contact-dependent signals can be sufficient. Cytotoxic T lymphocytes form immune synapses and release cytotoxic granules to kill islet cells in diabetic mice. On copper surfaces, the metal directly damages yeast membranes and DNA, representing a contact-mediated killing mechanism. Autotoxin-mediated latecomer killing in yeast involves secreted molecules that inhibit growth and induce death.
Target cell death execution
In simple terms: The target cell undergoes irreversible damage and dies.
The final stage is target cell death, which can occur through apoptosis, necrosis, or other death modalities depending on the effector mechanism [1, 7]. In NK cell-mediated antitumor activity, target cells die via granule exocytosis or death receptor pathways. In CTL-mediated killing of islet cells, apoptosis is the predominant mode, as observed by intravital imaging. Copper surface killing results in loss of membrane integrity and cell death. Yeast latecomer killing leads to colony death, which can be quantified by colony-forming unit assays.
Regulation by circadian and metabolic cues
In simple terms: The timing and intensity of killing can be controlled by the body clock and metabolism.
Neutrophil bactericidal activity is optimized by a light-regulated circadian timer, boosting daytime immunity. This indicates that killing of cells of another organism is not constitutive but subject to temporal regulation. Metabolic state and synthetic compounds can also modulate killing capacity; TPEN variants improve selective killing of cancer cells. These regulatory layers ensure that killing is deployed when needed and avoid collateral damage [2, 3].
Key Genes Involved in GO:0031640 killing of cells of another organism
The following genes and proteins are experimentally implicated in killing of cells of another organism, based on the verified literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| NKG2D | Activating receptor on NK cells | Mediates recognition of stressed target cells in antitumor killing |
| KIR | Inhibitory receptor on NK cells | Regulates NK cell killing of target cells |
| Perforin | Pore-forming protein in cytotoxic granules | Essential for CTL and NK cell-mediated killing [1, 7] |
| Granzyme B | Serine protease in cytotoxic granules | Induces apoptosis in target cells during immune killing [1, 7] |
| FasL | Death receptor ligand | Triggers apoptosis in target cells during CTL killing |
| TNF-alpha | Cytokine | Contributes to killing of intracellular pathogens |
| IFN-gamma | Cytokine | Enhances NK cell killing of Mycobacterium tuberculosis |
| CLOCK | Circadian transcription factor | Regulates neutrophil bactericidal activity |
| BMAL1 | Circadian transcription factor | Partners with CLOCK to control killing rhythms |
| TPEN | Synthetic metal chelator | Selectively kills cancer cells |
| Copper surface proteins | Membrane and DNA targets | Mediate contact killing of yeast on metallic copper |
| Autotoxin | Secreted yeast toxin | Mediates latecomer killing in yeast communities |
| Mycobacterium tuberculosis H37Rv | Intracellular pathogen | Target of NK cell-mediated killing |
| Islet cell autoantigens | Targets in autoimmune diabetes | Killed by CTLs in diabetic mice |
| Stem cells from IVF embryos | Potential source of cells | Discussed in context of life continuation |
How Is killing of cells of another organism Regulated?
Killing of cells of another organism is regulated at multiple levels. Circadian clocks, including CLOCK and BMAL1, optimize neutrophil bactericidal activity to boost daytime immunity. Cytokine signals such as IFN-gamma and TNF-alpha modulate NK cell killing of intracellular pathogens. Inhibitory receptors like KIR fine-tune NK cell cytotoxicity to prevent excessive killing. Synthetic compounds such as TPEN variants can enhance selective killing of cancer cells. These regulatory mechanisms ensure that killing is targeted and temporally controlled.
killing of cells of another organism and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NKG2D | Cancer | NK cell co-culture with tumor cells |
| Perforin | Autoimmune diabetes | CTL killing of islet cells in mice |
| IFN-gamma | Tuberculosis | NK cell killing of M. tuberculosis |
| CLOCK | Bacterial infection | Neutrophil bactericidal assay |
| TPEN | Cancer | Selective cancer cell killing assay |
Cancer immunotherapy
Natural killer cells exhibit antitumor activity by directly killing malignant cells, making GO:0031640 central to cancer immunotherapy. Enhancing NK cell killing through receptor engineering or cytokine stimulation is a major therapeutic strategy. Selective killing of cancer cells by synthetic compounds like TPEN variants further highlights the potential of targeting this process.
Autoimmune diabetes
In type 1 diabetes, cytotoxic T lymphocytes kill pancreatic islet cells, a process visualized by intravital imaging in diabetic mice. This aberrant killing of self-cells represents a failure of self-tolerance and is a key target for therapeutic intervention.
Infectious diseases
Human natural killer cells mediate killing of intracellular Mycobacterium tuberculosis H37Rv via granule-independent mechanisms, linking GO:0031640 to tuberculosis immunity. Circadian regulation of neutrophil bactericidal activity also impacts susceptibility to bacterial infections.
Antimicrobial surfaces and microbial competition
Contact-mediated killing of yeast cells on dry metallic copper surfaces demonstrates how abiotic surfaces can induce killing of another organism's cells. Autotoxin-mediated latecomer killing in yeast communities illustrates microbial competition through killing.
From killing of cells of another organism-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X mediate NK cell killing of tumor cells? | CRISPR knockout of gene X in NK cells followed by co-culture |
| Does a point mutation in perforin affect CTL killing? | Knock-in of mutant perforin in CTLs |
| Can overexpression of IFN-gamma enhance killing of M. tuberculosis? | Overexpression of IFN-gamma in NK cells |
| Does CLOCK regulate neutrophil bactericidal activity? | Knockout of CLOCK in neutrophils |
| Does TPEN variant selectively kill cancer cells? | Point mutation in TPEN target or overexpression |
| Does copper surface kill yeast via specific genes? | Knockout of yeast genes followed by copper exposure |
How to Study the killing of cells of another organism Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Co-culture killing assay | Target cell viability after effector exposure | NK cell killing of tumor cells |
| Colony-forming unit assay | Bacterial survival after NK cell killing | M. tuberculosis killing |
| Intravital imaging | Real-time CTL killing of islet cells | Autoimmune diabetes models |
| Flow cytometry | Apoptosis and viability of target cells | Cytotoxicity quantification |
| CRISPR knockout screen | Genes required for killing | Functional genomics of killing |
| Circadian behavioral assay | Timing of bactericidal activity | Neutrophil killing rhythms |
| Copper surface exposure | Yeast cell death on metallic copper | Antimicrobial surface testing |
| Autotoxin killing assay | Latecomer yeast death | Microbial competition |
Co-culture killing assays
Co-culture of effector cells (e.g., NK cells or CTLs) with target cells (e.g., tumor cells or infected macrophages) followed by viability measurement is the gold standard for studying GO:0031640 [1, 6]. Colony-forming unit assays quantify killing of Mycobacterium tuberculosis.
Intravital imaging
Intravital imaging allows real-time visualization of CTL killing of islet cells in diabetic mice, providing spatial and temporal resolution of the killing process. This method is powerful for understanding dynamics in vivo.
Flow cytometry and cytotoxicity assays
Flow cytometry-based cytotoxicity assays measure target cell death by staining for viability dyes or apoptosis markers after co-culture with effector cells. This approach is high-throughput and quantitative.
CRISPR screens and genetic perturbation
CRISPR knockout or activation screens in effector or target cells can identify genes that regulate killing of cells of another organism [1, 6]. These screens are complemented by validation experiments using individual knockouts.
How CRISPR Can Be Used to Study GO:0031640 killing of cells of another organism
Knockout
CRISPR knockout of candidate genes in effector cells (e.g., NK cells, CTLs) or target cells enables causal testing of their role in killing of cells of another organism [1, 6]. For example, knockout of perforin or granzyme B abolishes CTL-mediated killing.
Point Mutation
Point mutations can be introduced to dissect specific residues required for killing, such as in perforin or NKG2D [1, 7]. This approach reveals structure-function relationships without abolishing protein expression.
Knock-in
Knock-in of tagged or reporter genes allows tracking of effector proteins during killing. For instance, knock-in of fluorescently tagged perforin enables live imaging of granule release.
Overexpression
Overexpression of killing effectors or regulatory cytokines (e.g., IFN-gamma) can enhance killing capacity and is used to study gain-of-function phenotypes. Overexpression of TPEN targets may increase sensitivity to synthetic killing compounds.
How EDITGENE Supports killing of cells of another organism Research
Researchers studying killing of cells of another organism-related genes often need to determine whether a candidate gene is causally involved in the killing process or merely correlated with it. EDITGENE provides comprehensive CRISPR services to enable such causal studies.
Contact EDITGENE today to design your custom CRISPR model for killing of cells of another organism research.
Frequently Asked Questions About killing of cells of another organism
What is GO:0031640?
GO:0031640 is the Gene Ontology term for killing of cells of another organism, defined as any process in an organism that results in the killing of cells of another organism.
What genes are involved in killing of cells of another organism?
Key genes include NKG2D, KIR, perforin, granzyme B, FasL, TNF-alpha, IFN-gamma, CLOCK, and BMAL1, among others [1, 2, 6, 7].
How is killing of cells of another organism studied?
It is studied using co-culture killing assays, intravital imaging, flow cytometry, and CRISPR screens [1, 6, 7].
What is the difference between GO:0031640 and apoptosis?
GO:0031640 specifically refers to killing induced by another organism, whereas apoptosis is cell-autonomous death due to internal signals.
Which cells perform killing of cells of another organism?
Natural killer cells, cytotoxic T lymphocytes, neutrophils, and yeast killer cells are examples [1, 2, 5, 6, 7].
Is killing of cells of another organism involved in cancer?
Yes, NK cells kill tumor cells, and this process is exploited in cancer immunotherapy.
Can CRISPR be used to study killing of cells of another organism?
Yes, CRISPR knockout, knock-in, and overexpression models are widely used to dissect the genes involved [1, 6].
What diseases are linked to defective killing of cells of another organism?
Defects can lead to chronic infections like tuberculosis, while excessive killing contributes to autoimmune diabetes [6, 7].
How does circadian rhythm affect killing of cells of another organism?
The circadian clock optimizes neutrophil bactericidal activity to boost daytime immunity.
What are the research methods for GO:0031640?
Common methods include co-culture assays, colony-forming unit assays, intravital imaging, and CRISPR screens [1, 4, 6, 7].
Conclusion
GO:0031640, killing of cells of another organism, is a fundamental biological process with broad relevance to immunity, infection, autoimmunity, and antimicrobial technology [1, 4, 6, 7]. Understanding its molecular players and regulatory mechanisms is essential for developing new therapies and interventions [1, 2, 3]. CRISPR-based models provide powerful tools to dissect the genetic basis of this process, and EDITGENE offers comprehensive services to support such research [1, 6].
References
- 1. Yang Q et al.. 2006. Antitumor activity of NK cells.. Immunol Res 36(1-3):13-25 PMID: 17337762
- 2. Du LY et al.. 2025. A light-regulated circadian timer optimizes neutrophil bactericidal activity to boost daytime immunity.. Sci Immunol 10(107):eadn3080 PMID: 40408429
- 3. Schaefer-Ramadan S et al.. 2019. Synthesis of TPEN variants to improve cancer cells selective killing capacity.. Bioorg Chem 87:366-372 PMID: 30913468
- 4. Quaranta D et al.. 2011. Mechanisms of contact-mediated killing of yeast cells on dry metallic copper surfaces.. Appl Environ Microbiol 77(2):416-26 PMID: 21097600
- 5. Oda AH et al.. 2022. Autotoxin-mediated latecomer killing in yeast communities.. PLoS Biol 20(11):e3001844 PMID: 36342925
- 6. Brill KJ et al.. 2001. Human natural killer cells mediate killing of intracellular Mycobacterium tuberculosis H37Rv via granule-independent mechanisms.. Infect Immun 69(3):1755-65 PMID: 11179353
- 7. Coppieters K et al.. 2012. Intravital imaging of CTLs killing islet cells in diabetic mice.. J Clin Invest 122(1):119-31 PMID: 22133877
- 8. Bongaerts GP et al.. 2007. Stem cells from residual IVF-embryos - Continuation of life justifies isolation.. Med Hypotheses 69(3):478-80 PMID: 17383111
