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0:00
Hi everyone. I appreciate
your interests in the
lecture about phagocytosis.
My name is Eileen Uribe-Querol,
and I'm an Associate Professor
at the School of Dentistry
at the National Autonomous
University of Mexico
in Mexico City.
0:19
Here is an overview
of our lecture.
In this lecture, we will discuss
the origins of phagocytosis.
We will also define the
concept of phagocytosis.
We will review the
different types of
phagocytic cells and discuss
the steps of the
phagocytic process.
The phagocytic steps are first,
the recognition of
the target particle,
the activation of that
internalization process,
the phagosome formation, and
finally, the
phagosome moderation.
0:55
The first observations
of phagocytosis.
In the 19th century,
Alexander Ecker,
Nathanael Lieberkuhn,
and Giulio Bizzozero,
saw Erythrocytes
inside cells. Ecker,
saw them inside
rabbit skin cells,
Lieberkuhn saw them
inside white blood cells,
and Bizzozero
inside macrophages.
Sir William Osler,
saw carbon particles
inside cells too,
while Robert Koch,
Paul Albert Grawitz
and Alexander Ogston,
saw bacteria and
fungi inside cells.
1:35
The origins of phagocytosis.
In the 1880s, Elie
Metchnikoff made
his original observation while
studying starfish larvae.
He stuck rose thorns
into starfish larvae.
He was amazed that
many special cells were
attacking the small thorns.
In his words, he said,
if a delicate glass
tube, a rose thorn or
a spine of sea urchin may be
introduced into one of these larvae,
the amoeboid cells of
the mesoderm collect
around the foreign body,
enlarge masses easily
visible with the naked eye.
Metchnikoff also
published a paper
describing the
phagocytic process.
In this publication, he used
the word phagocyte from phago,
that means eating,
and cyte, that means cells.
This term was adjusted
to Metchnikoff,
by his friend Carl
Frederick William Gauss.
Metchnikoff described the
role of phagocytes during
the metamorphosis of tadpole to
frog and disappearance
of the tail.
He also described the process of
phagocytosis against
foreign microorganisms.
Metchnikoff demonstrate
that phagocytosis
was mainly a function
of little cells.
Based on this observation,
Metchnikoff realized phagocytosis
was a defense mechanism.
With great results,
he moved into immunology and
endorsed the concept
of cellular immunity.
He won the Nobel Prize in 1908.