15 - Immunity Flashcards
Immunity is the ability of an organism to…
Resist infection or toxin through the action of specific antibodies or sensitised white blood cells
Immunity can be divided into categories…
Active or Passive
Natural or Artificial
Active = body produces new antibodies
Passive = antibodies are introduced from an outside source
Natural = through the body’s own mechanisms
Artifical = through medical intervention (e.g. vaccination)
Immunity can be divided into two types of response…
- Innate
- Adaptive (aquired)
Summarise the key differences between innate and adaptive immunity…
- Innate is present from birth, adaptive is not
- Innate response is rapid, adaptive is slow
- Innate involves simple recognition systems, adaptive is sophisticated and specific
- Innate has no memory, adaptive has specific memory
- Innate relies on common ‘danger’ signals, adaptive can ‘learn’
The body’s immune response takes place in 3 phases (in order)…
- Innate response
- Adaptive response
- Immunological memory
The innate response starts within minutes and lasts for days. It involves (3)…
- Inflammation
- Complement activation
- Phagocytosis and destruction of pathogens
The adaptive response occurs in six steps…
- Antigen-specific T cells are activated
- Antigen-specific B cells are activated
- Effector and memory T cells are formed
- T and B cell interactions, germinal centres formed, plasma cells formed/ antibody production, memory B cells formed
- Effector lymphocytes emigrate from peripheral lymphoid organs
- Effector cells and antibodies eliminate the pathogen
The final phase of the immune response is immunological memory. In this phase…
Memory B and T cells are maintained and high serum or mucosal antibody levels protect against reinfection
State 4 goals of the immune system
- Clear pathogens in a controlled and efficient manner
- Restore homeostasis
- Confer future protection
- Remove potential tumours
Name some factors that influence immunity…
General health, infections, nutrition, adverse environmental conditions, microbiome, pregnancy, genetic disorders, stress…
A vaccine can be described as a substance which…
Stimulates the production of antibodies, thus confering immunity against diseases
Explain herd immunity…
If a sufficient proportion of the population is immune, it becomes harder for the disease to spread. This protects everyone, even those who are not immune.
Name the 4 types of vaccine
- Live
- Inactivated
- Subunit
- Attenuated
(LISA)
What level of immunity in a population is required to prevent measles outbreaks?
>95%
Antibodies are produced by…
Plasma cells (a type of mature B lymphocyte)
Clonal selection
Lymphocytes with receptors specific to self are:
a) Deleted early in lymphoid cell development
b) Never present in lymphoid cell lines
c) Deleted after emigrating from the peripheral lymphoid organs
Clonal selection
Lymphocytes with receptors specific to self are:
a) Deleted early in lymphoid cell development
b) Never present in lymphoid cell lines
c) Deleted after emigrating from the peripheral lymphoid organs
Both myeloid and lymphoid lineages originate from which type of cell? Where is this cell type located?
They originate from pluripotent hematopoietic stem cells in the bone marrow
The primary lymphoid tissues are…
Bone marrow and thymus
The secondary lymphoid tissues include…
Peripheral lymphoid tissues (lymph nodes, spleen, MALTs, tonsils)
MALT stands for…
Mucosal Associated Lymphoid Tissue
MALT can be found in which areas of the body?
Respiratory and intestinal tracts
What happens in the primary lymphoid tissues?
Lymphocytes are produced and mature
What happens in secondary lymphoid tissues?
They are the site of the adaptive immune response
