Related Experiment Video
Updated: Aug 10, 2026
09:54
Methods for Rapid Transfer and Localization of Lyme Disease Pathogens Within the Tick Gut
Published on: February 15, 2011
Diverse Lyme disease spirochetes bind integrin alpha IIb beta 3 on human platelets
J Coburn1, S W Barthold, J M Leong
1Division of Rheumatology and Immunology, Tufts-New England Medical Center, Boston, Massachusetts 02111.
Infection and Immunity
|December 1, 1994
Summary
Infectious Lyme disease spirochetes bind to human platelets via integrin alpha IIb beta 3. This widespread binding among Borrelia species suggests a role in Lyme disease transmission and pathogenesis.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Lyme disease is a multisystemic infection caused by Borrelia burgdorferi.
- Previous studies indicated infectious Borrelia burgdorferi binds to human platelets through integrin alpha IIb beta 3.
Purpose of the Study:
- To investigate the platelet- and alpha IIb beta 3-binding activity of diverse Lyme disease spirochete strains.
- To determine if this binding is conserved across different Borrelia species that cause Lyme disease.
Main Methods:
- Tested 11 infectious strains of Borrelia burgdorferi sensu stricto, B. garinii, and B. afzelii for platelet binding.
- Utilized microtiter wells and suspension assays to assess binding.
- Employed blocking anti-alpha IIb beta 3 antibodies and purified alpha IIb beta 3 to confirm specificity.
- Assessed expression of outer surface proteins OspA, OspB, and OspC via immunoblotting.
Main Results:
- All 11 infectious Borrelia strains demonstrated binding to human platelets.
- Binding was specifically mediated by integrin alpha IIb beta 3.
- Non-infectious strains lacked alpha IIb beta 3 and platelet-binding activity.
- No correlation was found between platelet binding and OspA, OspB, or OspC expression.
Conclusions:
- Integrin alpha IIb beta 3-binding activity is a common characteristic of Borrelia species responsible for Lyme disease.
- This binding is strongly associated with infectivity.
- The findings support a significant role for alpha IIb beta 3 interaction in the transmission and/or pathogenesis of Lyme disease.
Related Concept Videos
01:10Integrins
Animal and protozoan cells do not have cell walls to help maintain shape and provide structural stability. Instead, these eukaryotic cells secrete a sticky mass of carbohydrates and proteins into the spaces between adjacent cells. This network of proteins and molecules is called an extracellular matrix or ECM.
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
01:15Activation of Integrins
Integrins bind ligands and transmit information from outside the cell to inside or vice-versa through an "outside-in signaling" or "inside-out signaling."
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
In "outside-in signaling," external factors in the extracellular space bind to exposed ligand binding sites on integrins. This causes the inactive protein to undergo a conformational change to become active. Integrins are often clustered on the cell membrane. Repetitive and regularly spaced ligand binding events provide an effective stimulus.
01:17Intracellular Signaling Affects Focal Adhesions
Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Some...
01:22Formation of the Platelet Plug
The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
01:26Rocky Mountain Spotted Fever
Rocky Mountain Spotted Fever (RMSF) is a severe tick-borne illness caused by Rickettsia rickettsii, a Gram-negative, coccobacillary bacterium. This pathogen is an obligate intracellular parasite, requiring a host cell for replication. Transmission occurs through the bite of an infected tick. In the United States, the most important vectors are Dermacentor variabilis (American dog tick) and Dermacentor andersoni (Rocky Mountain wood tick), though other tick species may also serve as vectors.