Transferrin Receptor-Mediated Drug Delivery Across the Blood–Brain Barrier
The blood–brain barrier restricts the passage of most antibodies, proteins, and nucleic-acid therapeutics into the central nervous system. Transferrin receptor 1—also known as TfR1, TFRC, or CD71—is widely investigated as a receptor-mediated transport route into the brain. However, successful delivery depends on more than binding TfR1: receptor expression, surface accessibility, affinity, valency, intracellular trafficking, and cargo release can determine whether a construct is transcytosed, recycled, retained in brain endothelium, or delivered to lysosomes.
- What Is Transferrin Receptor 1?
- Why Is the Blood–Brain Barrier Difficult to Cross?
- TfR1 as a Molecular Shuttle for Brain Drug Delivery
- Binding Is Not Delivery: Affinity, Avidity, and Valency
- TfR1 Trafficking Determines Cargo Fate
- A TfR1 Delivery-Validation Workflow
- TfR-Targeted Delivery of Antibodies and Biologics
- TfR-Targeted Oligonucleotide Delivery
- TfR1 in Cancer Research and Targeted Delivery
- References
Transferrin Receptor-Mediated Drug Delivery Across the Blood–Brain Barrier:
What Is Transferrin Receptor 1?
Iron-loaded transferrin binds TfR1 at the cell surface and is internalized through receptor-mediated endocytosis. Endosomal acidification facilitates iron release, while the TfR1–transferrin complex usually returns to the plasma membrane for another uptake cycle.
TfR1, TFRC, and CD71
TfR1 is the protein encoded by the TFRC gene and is also known as the cell-surface antigen CD71. These terms are frequently used interchangeably, although researchers may encounter them in different experimental contexts:
TFRC in gene and gene-expression studies; TfR1in receptor biology and drug delivery and CD71 in flow cytometry, immunophenotyping.
