Hello, first I would like to introduce myself.
My name is Pieter Hiemstra, and I'm from the Department of Pulmonology
at the Leiden University Medical Center in Leiden, The Netherlands.
In this talk, which is part of the Henry Stewart Talks Series
Cells of the Innate Immune System,
Henry Stewart talks series cells
and their role in the innate immune system.
In my talk, I will focus on the role of these peptides in the lung.
but, as you will see
Antimicrobial peptides are an essential element
of the innate immune system and essential for host defense
And the dramatic consequences of the interaction of an antimicrobial peptide
with a bacterium is shown in this EM image.
It shows what happens to Pseudomonas bacterium
after it has been exposed for 1½ or 3 hours
to an antimicrobial peptide of the family of the cathelicidins.
And what you can see most prominently after 3 hours
is the appearance of blasts on the outer surface of the bacterium,
indicating membrane injury.
And indeed, when considering the antimicrobial mechanisms
involved in the killing capacity of antimicrobial peptides
towards microorganisms it is known that disruption of membrane integrity
is a very, very essential mechanism.
In addition, for some peptides it has been shown
that there is intracellular activity of peptides after death.
after death. They have been translocated
Various cell types are able to produce antimicrobial peptides,
but it appears that on a quantitative basis
the main cellular sources of antimicrobial peptides
are the neutrophils and the epithelial cells.