Immunology
Lecture 1
30/11/2020
Immunology
Immunology: the scientific discipline that studies the immune system, which serves to protect your
body from infectious agents and cancer
Key concepts
- Innate vs adaptive immune system
- Specific vs aspecific immune responses
- Self vs non-self
- Immunological memory
- Immunity vs tolerance
- Cellular vs humoral immunity
- Differentiation and specialization of leucocytes
- Antibodies: specificity, selectivity, affinity
Immune system: protect against infectious diseases
- Microorganism: bacteria (intracellular and extracellular), viruses, parasites
- Multicellular parasites
Vaccines: critical, effective and safe (since 1798, by Jenner)
Specific germs cause specific diseases
Koch’s postulate: a critical step froward in identifying causal agents
- Theoretical and experimental prove that a specific germ causes a specific disease
o The germ is found in diseased but not healthy organisms
o The ger, can be isolated from the diseased organism
o The germ disease when transferred
o The germ can be isolated again
Infectious diseases
- Polio: highly contagious virus; paralysis and deformation in 1/200 patients
o Only in developing countries
- Measles: highly contagious virus, with very severe complications and often resulting in death
o Measles incidence is strongly increasing in Europe
o This time last year, children in Samoa were dying due to a recent outbreak of
measles. Death rate is 1,5% of all infected
- Diphtheria: bacterial infection, most common cause of pediatric death before a vaccin
became available
o After diagnosis: 10% of patients die with and 50% die without treatment
→ studying and understanding the interactions between infectious agents and the immune system
had led to eradication of the viral disease smallpox and strong reductions in the incidence of a large
series of other infectious diseases. With loss of confidence in vaccines, infectious diseases reappear.
The vaccine
- Pathogen can develop
- Vaccine can not be effective after a while anymore
COVID-19
- Caused by the infectious agent SAR-Cov-2
- No one has immunity
- Infectious: virus in the body, but not sick
- Vaccination: immune system is exposed to infection → protective immune response (2 years)
1
, o Don’t know for how long this vaccin will work
o Cytotoxic T cells are part of the immune system that respond to an infection when
you are already vaccinated
- Severe disease in COVID-19 is more common in elderly people
o Severe acute respiratory syndrome coronavirus 2
o By immune response of the virus, not the virus itself
▪ Fluid starts leaking to the lungs because epithelial cells are affected
o Long-term symptoms(long covid): reported in all age groups
▪ Pains, fever up to 6 months after the infection
o Elderly: comorbidities, other medical conditions
▪ Why elderly are more affected by COVID
Do vaccines actually help?
- Meningococcal disease: caused by a bacteria that can inhabit the mouth and throat, in rare
occasions, the bacteria can enter the circulation leading to sepsis and meningitis
(hersenvliesontesteking), with a death rate of around 10% and severe complications with the
survivors including neurological symptoms, deformations and amputations
- In 2002, a vaccination programs against type C has nearly eradicated this meningococcus
type
- Meningococcus type W (zero type) has seen strong increase since 2017, and is very
aggressive leading to a new vaccination program for this disease
More vaccines are needed
- Infect the lungs, RNA virus
- RSV, a cause of common cold with yearly seasonal epidemics around the globe
- In preterm infants RSV can cause very severe complications, in susceptible children, also
those carried to term, RSV infections the first year contribute to asthma inception
- In non-western countries, RSV epidemics completely congest the healthcare system
- most children cause of death in children
- COVID-19 vaccines
o Mostly directed to the spike (s) protein, the protein that the virus uses to enter the
cells int eh nose or the airways
o This vaccine can be delivered in various ways
o Indicated virions might be used as vaccine
2
, o The current vaccines seem effective in clinical studies
- SARS-Cov-2 vaccines
o A successful SARS-Co-2 vaccine might work through a variety of immunological
mechanisms, involving the innate immune system and activation of the adaptive
immune response and establishment of memory B cells (antibody production) and
memory T cells (cell mediated virus
response)
Immunology
Clearly, a potent immune response is of critical
importance to combat infectious disease
- Cells of the immune system
o White blood cells/leukocytes: the most important cells in the immune system,
however other cells also play an important role, including epithelial and endothelial
cells
▪ Leucocytes originate form the hematopoietic stem cell
▪ Mature leukocytes often circulate the body using the blood and lymph
systems. However, tissue also harbor a large number of specialized tissue-
resident leukocytes
- The immune response
o Innate immune system:
Immediately response
▪ Born with it
▪ Respond to all pathogens
in the same way
▪ Recognize microbes, try to
‘eat’ them
o Adaptive response: long term
response
▪ Develops to specific virus
▪ Covid
▪ Active
3
, o Phases
- Innate vs adaptive immune system
o Innate
▪ Inflammation, complement activation, phagocytosis, and destruction of
pathogen
▪ Specificity: groups of microorganisms
▪ Fast response, first defense
• Always active
▪ Act within minutes
▪ Encoded in the germline DNA
• Memory response by epigenetic programming only
▪ Depends on the barriers, phagocytes, dendritic cells
▪ Inflammatory response: when microbe passed epithelial barrier → redness,
swelling, pain → clearing the pathogen
▪ Infection: microbes enters the tissue
▪ Inflammatory: recognition by innate immune system
▪ Immunity: building response to pathogen
▪ Humoral: proteins in solution
• Complemtn system
• Anti-microbial peptides
• Antibodies
o Adaptive
▪ Interaction of T cells with B cells, formation of germinal centers. Formation
of effector B cells (plasma cells) and memory B cells. Production of antibody
▪ Specificity: a single (protein) antigen
▪ Slow response, very powerful
▪ Induced by specific trigger
▪ Requires DNA arrangements
• Source of specific immunological memory and basis for vaccination
▪ Days or weeks
▪ May be lifelong protection (memory)
▪ Typically something of higher organisms (birds, mammals)
• The different parts of the immune system have evolved at different
moments in evolution
▪ Greated degree of diversity, and has a specific memory respons
4
Lecture 1
30/11/2020
Immunology
Immunology: the scientific discipline that studies the immune system, which serves to protect your
body from infectious agents and cancer
Key concepts
- Innate vs adaptive immune system
- Specific vs aspecific immune responses
- Self vs non-self
- Immunological memory
- Immunity vs tolerance
- Cellular vs humoral immunity
- Differentiation and specialization of leucocytes
- Antibodies: specificity, selectivity, affinity
Immune system: protect against infectious diseases
- Microorganism: bacteria (intracellular and extracellular), viruses, parasites
- Multicellular parasites
Vaccines: critical, effective and safe (since 1798, by Jenner)
Specific germs cause specific diseases
Koch’s postulate: a critical step froward in identifying causal agents
- Theoretical and experimental prove that a specific germ causes a specific disease
o The germ is found in diseased but not healthy organisms
o The ger, can be isolated from the diseased organism
o The germ disease when transferred
o The germ can be isolated again
Infectious diseases
- Polio: highly contagious virus; paralysis and deformation in 1/200 patients
o Only in developing countries
- Measles: highly contagious virus, with very severe complications and often resulting in death
o Measles incidence is strongly increasing in Europe
o This time last year, children in Samoa were dying due to a recent outbreak of
measles. Death rate is 1,5% of all infected
- Diphtheria: bacterial infection, most common cause of pediatric death before a vaccin
became available
o After diagnosis: 10% of patients die with and 50% die without treatment
→ studying and understanding the interactions between infectious agents and the immune system
had led to eradication of the viral disease smallpox and strong reductions in the incidence of a large
series of other infectious diseases. With loss of confidence in vaccines, infectious diseases reappear.
The vaccine
- Pathogen can develop
- Vaccine can not be effective after a while anymore
COVID-19
- Caused by the infectious agent SAR-Cov-2
- No one has immunity
- Infectious: virus in the body, but not sick
- Vaccination: immune system is exposed to infection → protective immune response (2 years)
1
, o Don’t know for how long this vaccin will work
o Cytotoxic T cells are part of the immune system that respond to an infection when
you are already vaccinated
- Severe disease in COVID-19 is more common in elderly people
o Severe acute respiratory syndrome coronavirus 2
o By immune response of the virus, not the virus itself
▪ Fluid starts leaking to the lungs because epithelial cells are affected
o Long-term symptoms(long covid): reported in all age groups
▪ Pains, fever up to 6 months after the infection
o Elderly: comorbidities, other medical conditions
▪ Why elderly are more affected by COVID
Do vaccines actually help?
- Meningococcal disease: caused by a bacteria that can inhabit the mouth and throat, in rare
occasions, the bacteria can enter the circulation leading to sepsis and meningitis
(hersenvliesontesteking), with a death rate of around 10% and severe complications with the
survivors including neurological symptoms, deformations and amputations
- In 2002, a vaccination programs against type C has nearly eradicated this meningococcus
type
- Meningococcus type W (zero type) has seen strong increase since 2017, and is very
aggressive leading to a new vaccination program for this disease
More vaccines are needed
- Infect the lungs, RNA virus
- RSV, a cause of common cold with yearly seasonal epidemics around the globe
- In preterm infants RSV can cause very severe complications, in susceptible children, also
those carried to term, RSV infections the first year contribute to asthma inception
- In non-western countries, RSV epidemics completely congest the healthcare system
- most children cause of death in children
- COVID-19 vaccines
o Mostly directed to the spike (s) protein, the protein that the virus uses to enter the
cells int eh nose or the airways
o This vaccine can be delivered in various ways
o Indicated virions might be used as vaccine
2
, o The current vaccines seem effective in clinical studies
- SARS-Cov-2 vaccines
o A successful SARS-Co-2 vaccine might work through a variety of immunological
mechanisms, involving the innate immune system and activation of the adaptive
immune response and establishment of memory B cells (antibody production) and
memory T cells (cell mediated virus
response)
Immunology
Clearly, a potent immune response is of critical
importance to combat infectious disease
- Cells of the immune system
o White blood cells/leukocytes: the most important cells in the immune system,
however other cells also play an important role, including epithelial and endothelial
cells
▪ Leucocytes originate form the hematopoietic stem cell
▪ Mature leukocytes often circulate the body using the blood and lymph
systems. However, tissue also harbor a large number of specialized tissue-
resident leukocytes
- The immune response
o Innate immune system:
Immediately response
▪ Born with it
▪ Respond to all pathogens
in the same way
▪ Recognize microbes, try to
‘eat’ them
o Adaptive response: long term
response
▪ Develops to specific virus
▪ Covid
▪ Active
3
, o Phases
- Innate vs adaptive immune system
o Innate
▪ Inflammation, complement activation, phagocytosis, and destruction of
pathogen
▪ Specificity: groups of microorganisms
▪ Fast response, first defense
• Always active
▪ Act within minutes
▪ Encoded in the germline DNA
• Memory response by epigenetic programming only
▪ Depends on the barriers, phagocytes, dendritic cells
▪ Inflammatory response: when microbe passed epithelial barrier → redness,
swelling, pain → clearing the pathogen
▪ Infection: microbes enters the tissue
▪ Inflammatory: recognition by innate immune system
▪ Immunity: building response to pathogen
▪ Humoral: proteins in solution
• Complemtn system
• Anti-microbial peptides
• Antibodies
o Adaptive
▪ Interaction of T cells with B cells, formation of germinal centers. Formation
of effector B cells (plasma cells) and memory B cells. Production of antibody
▪ Specificity: a single (protein) antigen
▪ Slow response, very powerful
▪ Induced by specific trigger
▪ Requires DNA arrangements
• Source of specific immunological memory and basis for vaccination
▪ Days or weeks
▪ May be lifelong protection (memory)
▪ Typically something of higher organisms (birds, mammals)
• The different parts of the immune system have evolved at different
moments in evolution
▪ Greated degree of diversity, and has a specific memory respons
4
