HOW ONCOLYTIC
VIRUSES WORK
The second phase is what makes the first phase matter. Direct viral cell killing triggers immunogenic cell death โ and the immune cascade that follows is the point.
The Two-Phase Mechanism
Neither phase is sufficient alone. The combination is what the clinical data reflects.
- 1
Viral Entry
The virus enters any cell it can reach. Entry is not selective โ the selectivity comes from what happens next.
- 2
Interferon Defence Check
Normal cells activate type I interferon signalling, preventing replication or inducing controlled death. Cancer cells with disabled pathways cannot mount this defence.
- 3
Selective Replication
The virus replicates using cancer cell machinery. Thousands of viral copies accumulate inside the cell.
- 4
Cell Lysis
The cell ruptures, releasing viral copies and tumour antigens. Neighbouring cancer cells are infected and the cycle repeats.
- 5
Immunogenic Cell Death
Calreticulin, HMGB1, and ATP are released โ danger signals that activate innate immune sensors. This is not the clean, contained death of apoptosis; it's inflammatory and flags the immune system.
- 6
Dendritic Cell Processing
Dendritic cells process tumour antigens from lysed cells and present them to T cells. T cells are activated against tumour-specific antigens.
- 7
Systemic T-Cell Response
Trained T cells circulate from the injection site. At distant sites expressing the same antigens, they attack โ producing responses at uninjected tumours.
Key Mechanistic Concepts
Five concepts with direct clinical implications for patients evaluating oncolytic virus therapy.
Immunogenic vs Non-Immunogenic Cell Death
Apoptosis doesn't trigger immune activation. Viral lysis does. The combination of calreticulin exposure, HMGB1 release, and ATP release is the biological trigger. This is why viral lysis generates immune response that most chemotherapy doesn't.
Cold-to-Hot Tumour Conversion
Cold tumours have no T-cell infiltration. Viral infection creates acute inflammation, recruits immune cells, transforms the microenvironment. Checkpoint inhibitors can then work on those T cells that are now present.
Transgene Payloads
Next-generation constructs carry IL-12, IL-15, anti-PD-1 fragments, and bispecific T-cell engagers โ all expressed within the tumour microenvironment, avoiding systemic toxicity.
Viral Spread Kinetics
Replication and spread depend on tumour architecture, vascularity, and the immune response the virus simultaneously triggers. Pre-existing neutralising antibodies can limit spread.
Frequently Asked Questions
Mechanism Questions
How CancerFax Helps
CancerFax is a specialist cancer access and patient-navigation platform. We help patients and families understand their options, organise medical records, coordinate hospital communication, and support cross-border treatment planning where appropriate.
We help collect and organise reports, scans, pathology, biomarker results, and treatment history for structured case review.
We communicate with hospitals or trial teams to assess whether a case may be suitable for further screening.
We support appointment coordination, document submission, translation, and direct communication with international departments.
For international patients, we help with practical coordination โ travel planning, hospital admission guidance, and local support.
If this option is not suitable, we help explore other relevant treatments, clinical trials, or advanced care pathways.
From inquiry through to follow-up, our coordinators provide a single point of contact for the family.
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This content is for informational purposes only and does not constitute medical advice. Always consult a qualified oncologist before making treatment decisions.