Fighting Cancer at the Nano Level

What am I looking at?

This is a colored scanning electron microscopy image of human dendritic cells interacting with T cells after absorbing nanoparticles bound to cancer-specific peptides. The dendritic cells are green (1) and the T cells are pink (2). The nanoparticles themselves cannot be seen in this image; they are contained within the dendritic cells at this stage.

Biology in the background

The concept of immunotherapy for cancer is based on the idea of getting the patient’s own immune system to fight cancerous cells. This concept has been around for a while, but progress in the field has faced several roadblocks. The main confounding issue has been how to get the immune system to target just the cancer cells and not healthy cells. However, breakthroughs in personalized medicine have allowed researchers to isolate unique peptides from an individual patient’s cancer cells and use nanoparticles to present them to the immune system as antigen targets.

Immune cells are key to this process. The peptide-bound nanoparticles are injected into the patient and are absorbed by their dendritic cells. Dendritic cells present antigens to other cells in the immune system, signaling the presence of a pathogen and conveying the ability to recognize it. Helper T cells are heavily involved in this process. Once they encounter an antigen, they can activate different immune responses that identify and destroy the cancer cells that present these antigens.

In humans, dendritic cells can grow up to 15 micrometers across, or roughly five times smaller than the width of a human hair. T cells can grow up to 10 micrometers across, or roughly 7.5 times smaller than the width of a human hair.

Technique

This image was created using scanning electron microscopy.