Immunology AI Flashcards
What are the expected events after injection of a vaccine in a healthy animal?
- Virus infects host cells, causing lysis of some cells
- Viral proteins are taken up by resident dendritic cells and processed for presentation on MHC molecules
- Dendritic cells are activated when their PRRs recognise typical viral structures or DAMPs released from dying cells
- Dendritic cells carrying viral antigens migrate to local lymph nodes
- Dendritic cells interact with naïve T cells in the lymph node, activating any T cells that recognise the viral antigens on their MHC molecules
- Activated T cells provide help to B cells in the lymph node that also recognise viral antigens
- Activated B cells differentiate into plasma cells and produce antibodies specific for the virus
- Antibodies and activated T cells clear the virus from infected tissues.
Why is vaccination able to make use of the memory response of the immune system?
Immune responses develop more quickly and effectively after repeated exposure to the same antigens.
What are memory T and B cells?
They are long-lived cells produced during immune responses that are able to respond directly to their antigen, permitting more rapid production of antibodies by B cells, production of cytokines by CD4+ T cells, or generation of activated cytotoxic (CD8+) T cells.
What route of vaccination is commonly used in veterinary practice?
Most vaccines used in veterinary practice are administered by subcutaneous injection, where they will be absorbed systemically to generate an immune response in the lymph nodes and spleen.
Why is stimulation of local, mucosal immunity important for pathogens that normally infect mucosal surfaces?
Protective immunity depends on stimulation of local, mucosal immunity. Immune responses can be generated in mucosa-associated lymphoid tissue (MALT), rather than in the lymph nodes or spleen.
Where are mucosa-associated lymphoid tissues typically found in the body?
Mucosal tissues of the respiratory, gastrointestinal, and urogenital tracts.
What are autoinflammatory diseases and how are they different from autoimmune diseases?
Autoinflammatory diseases are caused by inappropriate activity of the innate immune system without activation of T cells or other components of the adaptive immune system. Autoimmune diseases, on the other hand, involve the immune system attacking normal cells and tissues.
Why are some diseases in veterinary medicine described as ‘immune-mediated’?
Some diseases in veterinary medicine are described as ‘immune-mediated’ because it isn’t clear whether they are autoimmune or autoinflammatory. Detailed research studies are often lacking to establish the exact cause of these diseases.
What is the association between autoimmune haemolytic anaemia and chronic lymphocytic leukaemia?
There is a strong association between the development of autoimmune haemolytic anaemia and underlying chronic lymphocytic leukaemia, where the malignant B cells produce autoantibodies causing red blood cell destruction.
Why do thymomas frequently develop myasthenia gravis?
Thymomas frequently develop myasthenia gravis due to the inappropriate production of antibodies against the acetylcholine-gated ion channels in the neuromuscular junction.
How do some drugs increase the risk of autoimmune reactions?
Some drugs increase the risk of autoimmune reactions by possibly changing the expression of genes that regulate the immune system or altering the structure of normal proteins in the body, causing the immune system to identify them as foreign.
Do vaccinations have a proven association with autoimmune disease in dogs and cats?
No, there is no proven association between vaccination and autoimmune disease in dogs and cats, although it is frequently reported anecdotally and included as a warning in the datasheet of some vaccine products.
What is molecular mimicry and how does it relate to autoimmune diseases?
Molecular mimicry is when bacteria or pathogens have molecular structures that are similar to normal host molecules. In some cases, the immune response against the pathogen may ‘cross-react’ with host tissues, leading to immune-mediated damage.
What role does the microbiome play in shaping the immune system?
The microbiome, consisting of bacteria, viruses, and fungi in the gut, upper respiratory tract, and on the skin, interacts with the immune system to shape its development and immune responses. Mice raised in sterile conditions, without a microbial community, have a decreased risk of many autoimmune diseases.
Are there any recommended interventions targeted at the microbiome for dogs and cats with immune-mediated diseases?
Currently, there is insufficient evidence to recommend probiotics, antibiotics, or any other intervention targeted at the microbiome in dogs and cats diagnosed with an immune-mediated disease.
What diagnostic tests may be considered when presented with a dog or cat showing signs of an autoimmune disease?
When presented with a dog or cat showing signs of an autoimmune disease, clinicians may consider performing a thorough history, including exposure to drugs and toxins, physical examination, and checking all peripheral lymph nodes.
What is the difference between immune-mediated (IMHA) and autoimmune (AIHA) diseases in dogs and cats?
In dogs and cats, diseases such as haemolytic anaemia are described as immune-mediated (IMHA) if they are specific for a normal self-antigen, while they are described as autoimmune (AIHA) if they are caused by an autoimmune response.
What are the general clinical features of autoimmune and autoinflammatory diseases?
The general clinical features of autoimmune and autoinflammatory diseases may differ depending on their causes. Autoimmune diseases depend on the location of the targeted self-antigen, while autoinflammatory diseases exhibit features similar to an acute phase response.
Give an example of an autoimmune disease where the antigen is expressed in a single location.
Autoimmune (lymphocytic) thyroiditis is an example of an autoimmune disease where the antigen is expressed in a single location, specifically the thyroid gland.
What autoimmune disease in dogs exhibits immune responses against nuclear proteins produced throughout the body?
Systemic lupus erythematosus, a rare autoimmune disease in dogs, exhibits immune responses specific for nuclear proteins produced in practically every cell in the body.
What are the clinical signs of autoinflammatory diseases?
Autoinflammatory diseases typically display features of an acute phase response, including intermittent fever, lethargy, malaise, generalized lymph node enlargement, and occasionally joint pain and arthritis.
What combination of mechanisms can some diseases involve?
Some diseases can involve a combination of autoinflammatory and autoimmune mechanisms, where they may begin as an autoinflammatory disease and progress to an autoimmune response if T cells become activated.
Which disease causes pyrexia, joint pain, swelling, inflammation, and deposition of amyloid proteins in multiple tissues?
Shar Pei fever, also known as Shar Pei Autoinflammatory Disease (SPAID), causes pyrexia, joint pain, swelling, inflammation, and deposition of amyloid proteins in multiple tissues.
What is the cause of primary hypoadrenocorticism in most cases?
In most cases of primary hypoadrenocorticism, the cause is an autoimmune response directed against antigens found only in the adrenal glands.