The most abundant viruses on earth are phages, viruses that infect bacteria. There are more phages on Earth than stars in the universe, and it is estimated that every second, billions of bacteria on Earth are being infected by a phage. To cope with such frequent phage infections, bacteria have evolved a sophisticated and multi-faceted immune system. An important part of the bacterial immune system is the CRISPR-Cas system, an adaptive immune system that allows bacteria to memorize past infections by storing genetic information “stolen” from the phage in the bacterial genome.
In the past few years, there has been a revolution in our understanding of the bacterial immune system. It has been discovered that in addition to CRISPR-Cas, bacteria encode over 100 different defense systems that allow them to actively defend against infection. Surprisingly, it was discovered that important components of the human innate immune system have evolved from bacterial systems whose role is to protect from phage infection.
The purpose of this course it to gain knowledge on principles of bacterial immunity against viruses, and to expose students to contemporary research in this rapidly developing field. The topics that will be covered are
- How viruses infect bacteria: phage structure, phage life cycle, phage assembly
- The bacterial adaptive immune system: CRISPR - discovery and mode of action
- CRISPR - evolution, applications and diagnostics
- The innate immune system of bacteria: Restriction modifications and additional systems
- Principles of bacterial innate immunity
- The revolution in the discovery of new bacterial defense systems
- Evolutionary origin of human innate immunity in bacterial defense systems
- Regulated cell death in bacterial immunity
- Phages fight back – how phages overcome bacterial defenses
- Phage lysogeny and communication between phages
- Application of bacterial immune systems and of phages in medicine and biotechnology
This short course will be taught in 3 lessons, each lesson of 3 hours.