The Logic of Immunity

Most of us appreciate the importance of the immune system yet have very little knowledge about how it actually works. If you fall into this camp and are curious to learn more about this intricate system, Bobby Cherayil's book is an excellent resource.

The Logic of Immunity: Deciphering an Enigma was published in January 2024 by John Hopkins University Press. It gives a great overview of this complex system, including several findings from the recent years. It also points out the many areas of ongoing research and open questions.

The book introduces the actors of the system and the many interactions between them:

• the various types of immune cells,
• the pathogens and pathogen-associated patterns they recognize,
• the cascade of events that ultimately leads to an immune response.

The opening chapter explains (and visualizes!) where these cells are located. It explains how they contribute to the immune response, and how we broadly categorize them into innate and adaptive immunity.

Chapters 2 and 3 discuss the innate immune system. We get to know the general concepts, like molecular patterns and receptors recognizing them. They describe in detail some well-studied mechanisms, like the LPS-TLR4 interaction. And we also learn the story of their research spanning multiple years and multiple discoveries building upon each other.

Chapters 4-6 delve into the mechanisms of adaptive immunity and their main cell types: B- and T-lymphocytes. Have you ever wondered how the immune system is able to "remember" earlier infections? You'll find here both an overview of "immune memory" and a detailed description how B and T cell proliferate and specialize.

Chapter 7 shows how these immune reactions are sometimes provoked by harmless substances - that's what we call allergy. Or even by human cells - that's what we call autoimmune diseases.

The next chapters put the immune system into a bigger context. They discuss the variability of immunity across different individuals and the many reasons behind it. Genes, environment, past infections, life style. A particularly fascinating part of "the human ecosystem" is the microbiota. Its importance has been recognized only in the last two decades. Chapter 8 introduces really well this emerging field of study.

Chapter 11 is dedicated to an immunology topic that affects all of us: vaccines. Building upon the knowledge from previous chapters, it explains how vaccines work.

Throughout the book, we learn a lot both about the exciting developments and the open questions in the field of immunology. Chapter 12 gives a summary of some trends of the last decades and an outlook for the next big puzzles to tackle.