Immunology of tropical infectious diseases
Written exam and a presentation. Every line on the overview slides can be an exam question. 5 points
for the presentation and 5 points for the discussion. Counts for 20% of both exams. The score can be
different for immunology and pathogenesis.
INTRODUCTION 14/02
Objective of the lectures:
1. Learn the basic principles of the innate immune system of the arthropod vector
2. Refresh basic knowledge about innate and adaptive immunity of the vertebrate host
3. Apply knowledge of innate and adaptive immunity to host-pathogen interactions
4. Understand the basis of successful infections through the skin and mucosal barriers
5. Understand the concept and examples of immune privilege
6. Learn about examples of immune escape
7. Relevance of the microbiome during host-pathogen interactions
1. INNATE IMMUNITY OF THE INVERTEBRATE HOST 23/02
Objectives:
1. Learn the basic principles of the innate immune system of the arthropod vector
2. What are major pathogens transmitted by arthropods
3. What are the physiological barriers
4. What are the immunological barriers
5. What are the cells of the innate immune system
6. What are the major immune recognition pathways
7. What are the major immune effectors
8. Which opportunities exist to target the arthropod and the pathogens they transmit
Pagina 1 van 90
, INVERTEBRATES AS PARASITE HOSTS AND DISEASE VECTORS
Various pathogens transmitted by blood feeding arthropods:
- Mites: Rickettsia spp.
- Ticks: Lyme disease, babesiosis, theileriosis, TBEV
- Lice: Epidemic typhus (Rickettsia), trench fever, recurrent fever
- Mosquitoes:
o Protozoa: malaria
o Arboviruses: yellow fever, dengue, chikungunya, zika, WNV
o Nematodes: Wuchereria, Brugia (lymphatic filarids)
- Reduviid bugs: Chagas disease
- Dipters: Leishmaniasis and human African trypanosomiasis
When taking a blood meal, the arthropods can take up a pathogen or transmit a pathogen to another
vector. The pathogen has to enter the arthropod through the blood meal and in the end reach a place
where it can be transmitted again. Parasite life cycles depend on specific interactions with the vector:
Besides parasites, insects harbour a microbiome, including bacterial symbionts in the midgut. This is
interesting because you can modify the microbiome of insects and render them for example resistant
to certain pathogens.
ESTABLISHMENT IN THE ARTHROPOD GUT
Transmission relates to uptake of a blood meal. There are typical
physiological barriers / triggers during the migration of the pathogen from a
human environment to the midgut of an insect. It has to colonize the
arthropod midgut. Malphigian tubules are primitive kidneys that help in the
dehydration of the blood meal, to make sure you have fast removal of the
water of the blood meal.
The pathogen has to overcome the environment of the midgut:
- Change of temperature
- Blood bolus moves to digestive part: high pH, proteolytic activity & gut microbiota
- The PM represents a mechanical barrier (peritrophic matrix)
o PM consists of chitin & proteoglycans: make mesh through which pathogens cannot
migrate but nutrients can diffuse.
o Ectoperitrophic space: between the PM and the epithelium
▪ Interesting for pathogens to invade this
There is a layer of chitin (carbohydrate) that coats the inside and outside of the GIT of the insect. It is
also covered with a layer of lipid, which prevents an insect of desiccation. The entire GIT is chitin-based
except for the midgut where you have high digestion of proteins.
Pagina 2 van 90
Written exam and a presentation. Every line on the overview slides can be an exam question. 5 points
for the presentation and 5 points for the discussion. Counts for 20% of both exams. The score can be
different for immunology and pathogenesis.
INTRODUCTION 14/02
Objective of the lectures:
1. Learn the basic principles of the innate immune system of the arthropod vector
2. Refresh basic knowledge about innate and adaptive immunity of the vertebrate host
3. Apply knowledge of innate and adaptive immunity to host-pathogen interactions
4. Understand the basis of successful infections through the skin and mucosal barriers
5. Understand the concept and examples of immune privilege
6. Learn about examples of immune escape
7. Relevance of the microbiome during host-pathogen interactions
1. INNATE IMMUNITY OF THE INVERTEBRATE HOST 23/02
Objectives:
1. Learn the basic principles of the innate immune system of the arthropod vector
2. What are major pathogens transmitted by arthropods
3. What are the physiological barriers
4. What are the immunological barriers
5. What are the cells of the innate immune system
6. What are the major immune recognition pathways
7. What are the major immune effectors
8. Which opportunities exist to target the arthropod and the pathogens they transmit
Pagina 1 van 90
, INVERTEBRATES AS PARASITE HOSTS AND DISEASE VECTORS
Various pathogens transmitted by blood feeding arthropods:
- Mites: Rickettsia spp.
- Ticks: Lyme disease, babesiosis, theileriosis, TBEV
- Lice: Epidemic typhus (Rickettsia), trench fever, recurrent fever
- Mosquitoes:
o Protozoa: malaria
o Arboviruses: yellow fever, dengue, chikungunya, zika, WNV
o Nematodes: Wuchereria, Brugia (lymphatic filarids)
- Reduviid bugs: Chagas disease
- Dipters: Leishmaniasis and human African trypanosomiasis
When taking a blood meal, the arthropods can take up a pathogen or transmit a pathogen to another
vector. The pathogen has to enter the arthropod through the blood meal and in the end reach a place
where it can be transmitted again. Parasite life cycles depend on specific interactions with the vector:
Besides parasites, insects harbour a microbiome, including bacterial symbionts in the midgut. This is
interesting because you can modify the microbiome of insects and render them for example resistant
to certain pathogens.
ESTABLISHMENT IN THE ARTHROPOD GUT
Transmission relates to uptake of a blood meal. There are typical
physiological barriers / triggers during the migration of the pathogen from a
human environment to the midgut of an insect. It has to colonize the
arthropod midgut. Malphigian tubules are primitive kidneys that help in the
dehydration of the blood meal, to make sure you have fast removal of the
water of the blood meal.
The pathogen has to overcome the environment of the midgut:
- Change of temperature
- Blood bolus moves to digestive part: high pH, proteolytic activity & gut microbiota
- The PM represents a mechanical barrier (peritrophic matrix)
o PM consists of chitin & proteoglycans: make mesh through which pathogens cannot
migrate but nutrients can diffuse.
o Ectoperitrophic space: between the PM and the epithelium
▪ Interesting for pathogens to invade this
There is a layer of chitin (carbohydrate) that coats the inside and outside of the GIT of the insect. It is
also covered with a layer of lipid, which prevents an insect of desiccation. The entire GIT is chitin-based
except for the midgut where you have high digestion of proteins.
Pagina 2 van 90
