💊 Checkpoint Inhibitor Immunotherapy (Pembrolizumab) Simulator

T-cells Patrol for Tumor Antigens

Placeholder: T-cells constantly scan tissue for abnormal cells.

• ~10^7: T-cell receptor diversity (placeholder stat)
• Neoantigens: Tumor antigen types (placeholder stat)
• Minutes: Immune synapse time (placeholder stat)
• Variable: Baseline kill rate (placeholder stat)

Antigen recognition basics

Placeholder text: TCR engages MHC-presented tumor peptide.

Normal T-cell activation

Placeholder text: costimulation drives cytotoxic program.

Tumors Express PD-L1 to Hide

Placeholder: tumor cells upregulate PD-L1 under immune pressure.

• Common: PD-L1+ tumors (placeholder stat)
• IFN-γ: Induction driver (placeholder stat)
• CD274: PD-L1 gene (placeholder stat)
• IHC: Expression assay (placeholder stat)

Why tumors express PD-L1

Placeholder text: adaptive immune resistance mechanism.

Interferon feedback loop

Placeholder text: T-cell attack itself induces PD-L1.

PD-1/PD-L1 Delivers the Brake Signal

Placeholder: checkpoint engagement shuts down T-cell attack.

• CD279: PD-1 receptor (placeholder stat)
• Inhibitory: Signal type (placeholder stat)
• SHP-2: Downstream effect (placeholder stat)
• Self-tolerance: Normal role (placeholder stat)

Checkpoint signaling

Placeholder text: ITSM/ITIM motifs recruit phosphatases.

Hijacking self-tolerance

Placeholder text: tumor exploits a normal safety brake.

Placeholder highlight: PD-1 normally prevents autoimmunity.

Pembrolizumab Blocks PD-1

Placeholder: monoclonal antibody physically blocks the receptor.

• Anti-PD-1 mAb: Drug class (placeholder stat)
• PD-1 (CD279): Target (placeholder stat)
• 2014: Approval year (placeholder stat)
• IV infusion: Administration (placeholder stat)

Mechanism of blockade

Placeholder text: antibody outcompetes PD-L1 for PD-1.

Dose-response relationship

Placeholder text: higher dose increases receptor occupancy.

Restored T-cell Attack and Tumor Killing

Placeholder: brake removed, T-cell resumes cytotoxic function.

• Subset: Durable response rate (placeholder stat)
• Present: irAE risk (placeholder stat)
• PD-L1 CPS: Response marker (placeholder stat)
• Chemo/other: Combination use (placeholder stat)

Cytotoxic killing restored

Placeholder text: granzyme/perforin release resumes.

Risks of releasing the brake

Placeholder text: reduced braking can cause autoimmune-like effects.

Placeholder highlight: durable responses possible, side effects too.