Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING
GLOBETECH PUBLISHING
JIB

Coating of "Self” Peptides Protects Nanoparticles from Macrophage Destruction

By BiotechDaily International staff writers
Posted on 05 Mar 2013
Image: Diagram of Macrophage Interaction: Macrophages are immune cell “border guards” that have evolved to eat all sorts of foreign microbes, but they also eat many particles that are intended for therapeutics and imaging. A “Minimal peptide ‘Passport’” attached to the particles provides recognition signals so that the particles are not eaten, thus improving delivery to diseased cells in the body (Photo courtesy of Mary Leonard, Biomedical Art & Design, University of Pennsylvania).
Image: Diagram of Macrophage Interaction: Macrophages are immune cell “border guards” that have evolved to eat all sorts of foreign microbes, but they also eat many particles that are intended for therapeutics and imaging. A “Minimal peptide ‘Passport’” attached to the particles provides recognition signals so that the particles are not eaten, thus improving delivery to diseased cells in the body (Photo courtesy of Mary Leonard, Biomedical Art & Design, University of Pennsylvania).
Nanoparticles coated with peptides derived from the human protein CD47 were protected from uptake and destruction by macrophages in a genetically engineered mouse model system.

The membrane protein CD47 is reportedly a "marker of self" in mice that impedes phagocytosis of “self” molecules by signaling through the phagocyte receptor CD172a. CD47, which is found on almost all mammalian cell membranes, binds to the SIRPa macrophage receptor in humans.

Investigators at the University of Pennsylvania (Philadelphia, USA) used computers to design the smallest peptides from human CD47 (hCD47) that could perform the same function. They then synthesized these peptides and attached them to virus-size particles for intravenous injection into mice that had been genetically engineered to express a CD172a variant compatible with hCD47.

Results published in the February 22, 2013, issue of the journal Science revealed that the coating of “self” peptides delayed macrophage-mediated clearance of the nanoparticles, which promoted persistent circulation that enhanced dye and drug delivery to tumors.

"There may be other molecules that help quell the macrophage response," said senior author Dr. Dennis Discher, professor of chemical and biomolecular engineering at the University of Pennsylvania, "but human CD47 is clearly one that says, "Do not eat me. It can be made cleanly in a machine and easily modified during synthesis in order to attach to all sorts of implanted and injected things, with the goal of fooling the body into accepting these things as self."

Related Links:

University of Pennsylvania



comments powered by Disqus

Channels

Drug Discovery

view channel

Ibuprofen May Restore Immune Function in Older Individuals

New research suggests that macrophages from the lungs of old mice respond differently to infections than those of young mice, and ibuprofen given to the mice reversed these changes. New research using lab mice suggests that the solution to more youthful immune function might already be a common over-the-counter pain reliever.... Read more

Therapeutics

view channel
Image: Hair follicle (blue) being attacked by T cells (green) (Photo courtesy of Christiano Lab/Columbia University Medical Center).

Hair Restoration Method Clones Patients’ Cells to Grow New Hair Follicles

Researchers have developed of a new hair restoration approach that uses a patient’s cells to grow new hair follicles. In addition, the [US] Food and Drugs Administration (FDA) recently approved a new drug... Read more

Lab Technologies

view channel
Image: Leica Microsystems launches the inverted research microscope platform Leica DMi8 (Photo courtesy of Leica Microsystems).

New Inverted Microscope Designed to Readily Adapt to Changing Research Demands

A new inverted microscope for biotech and other life science laboratories was designed to readily accommodate modifications and upgrades to allow it to keep current with changing research demands and interests.... Read more

Business

view channel

Partnership Established to Decode Bowel Disease

23andMe (Mountain View, CA,USA), a personal genetics company, is collaborating with Pfizer, Inc. (New York, NY, USA), in which the companies will seek to enroll 10,000 people with inflammatory bowel disease (IBD) in a research project designed to explore the genetic factors associated with the onset, progression, severity,... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.