SCIENCE science.org 5 NOVEMBER 2021 • VOL 374 ISSUE 6568 697IMAGE: PHILIP LAIBACHER
I
n 1882, in a private laboratory in Sicily,
Ukrainian microbiologist Ilya Mech-
nikov pierced starfish larvae with a
thorn from a nearby bush and watched
as some of the organism’s cells moved
toward the injury. The cells, he hypoth-
esized, were moving there to engulf any
disease-causing microbes that might dare
to enter the wound. The cells Mechnikov
observed were later named phagocytes—
“phago” is Greek for “eating” and “cyte” is
Greek for “cell”—and the cell best able to
“eat” microbes came to be called the mac-
rophage (“the big eater”). For this discovery,
Mechnikov won a Nobel Prize in 1908.
Fast-forward a little more than a century
to today, when immune system enthusiasts
can celebrate the microbiologist’s visionary
breakthrough with a macrophage enamel
pin ( 1 ) or a poster-sized illustration of the
“immune system battlefield” ( 2 ). Both prod-
ucts are available on the retail site affiliated
with the popular YouTube channel Kurzges-
agt (German for “in a nutshell”), which posts
easy-to-understand animations on a variety
of scientific subjects, from black holes to
dinosaurs, for an audience of more than 16IMMUNOLOGYA YouTuber’s vividly illustrated immune system
explainer delights and informs
By Daniel M. DavisImmunology meets the masses
million subscribers. With little formal sci-
ence education, the site’s creator, Philipp
Dettmer, has become one of the world’s most
influential science communicators, thanks in
great part to the clear scripts and vivid art
and design of the site’s videos.
The nitty gritty of the immune system is
of particular interest to Dettmer, who was di-
agnosed with cancer at the age of 32. Know-
ing that it would be difficult to capture the
complexity of this system in a 10-minute ani-
mation, he has written a book, Immune, that
charts the vast array of different immune
cells, what they do, the way they communi-
cate with each other, and what happens when
things go wrong. The book’s colorful illustra-
tions are reminiscent of those that appear in
Kurzgesagt’s video explainers and are among
the best I have seen in any scientific text.
Throughout the book, Dettmer uses won-
derful, original metaphors to explain im-
mune function, which build—layer upon
layer—as the details of this complex sys-
tem unfold. In chapter 17, for example, he
likens the diversity of immune recognition
to planning a fantastical dinner party for
millions of guests, each of whom is very
particular about what they like. From basic
kitchen ingredients, which represent gene
segments, he shows how 3,577,446 different
dinners can be made.
Along the way, Dettmer covers many pro-
found immunological principles, such as how
a body is able to detect foreign entities—frombacteria to transplanted organs—and how it
can recognize a virus that has only recently
come into existence. Over the course of two
chapters, with the help of a vivid illustration
of the B cell “career,” likening the activation
process to online encryption, he lucidly de-
scribes how antibodies are produced by
B cells and are selected to target a particular
pathogen. “B Cells are very dangerous cells,”
he writes, “so they need a strict two-factor
authentication to be truly activated.”
Some experts might be uncomfortable
with the colorful language Dettmer reg-
ularly uses. Receptor proteins on cell sur-
faces are, in Dettmer’s phrasing, “the noses
of your cells,” and when they activate a
macrophage, it gets “angry,” sending out
“octopus-like arms” to engulf bacteria. In
another passage, he likens different types
of T cells to the classes and subclasses of
characters used in the role-playing game
Dungeons & Dragons. But make no mis-
take, Dettmer’s chatty and accessible tone
is intentional, helping readers to process an
enormous amount of complex information.
The outcome is reminiscent of Bill Bryson’s
The Body—fast-paced and full of wonder.
There is relatively little in Dettmer’s book
about the people who shaped our under-
standing of the immune system or about the
experiments they performed to glean this in-
formation. There is a place for such stories,
but this book’s narrative is driven instead by
the timeline of an immune response, freeing
Dettmer from the jargon and precision that
might otherwise have weighed down the text.
Antibodies, T cells, and B cells were once
rarely discussed outside of research labs
and scientific talks, but thanks to COVID-19,
everyone, it seems, has become an immune
system enthusiast. Now, more than ever,
there is a hunger for details about this
complex biological process, and Dettmer’s
book is the feast we have been waiting for.
Although he could not have anticipated
how his research would be made accessible
to the public more than a century later, I
cannot help but think Mechnikov would be
delighted at Dettmer’s efforts. jREFERENCES AND NOTES- Macrophage Enamel Pin, https://shop-us.kurzgesagt.
org/products/macrophage-enamel-pin. - Immune System Battlefield Poster, https://shop-us.
kurzgesagt.org/products/immune-battlefield-poster.
Colorful cartoon renderings of immune function pepper the pages of this accessible introduction to immunology. 10.1126/science.abm0134
The reviewer is at the Lydia Becker Institute of Immunology
and Inflammation, The University of Manchester, Manchester
M13 9PL, UK, and the author of The Secret Body (Princeton
Univ. Press, 2021) and The Beautiful Cure (Penguin Random
House, 2018). Email: [email protected]Immune: A Journey into
the Mysterious System
That Keeps You Alive
Philipp Dettmer
Random House, 2021.
368 pp.INSIGHTS