Week 4 Immunodeficiency and immunomodulation Flashcards
(126 cards)
What are the General principles of immune response?
Main physiological function is to protect from infection
Multilayer defense
Network of pathogen recognition
Adaptive responses to changing pathogen
Multiple mechanisms of pathogen clearance
Effective inter-cellular communication
Limitation of host damage
Self-regulation
what is the importance of patern recognition receptor ?
structures on macrophages–> can differentiate between gram positive, negative bacteria, fungi and virus
tell you what type of pathogen the body is dealing
What are the Major Components of the Innate Immune System?
Pattern recognition receptors
(PRR
Antimicrobial peptides
Cells
Cytokins
Complement components
What is the function of B cells?
develop potential to secret antibodies: humoral immunity
what are the different types of T cells and there function?
Killer or cytotoxic T lymphocytes are able to kill. Cellular immunity
Helper T lymphocytes secrete growth factors (cytokines) which control immune response: Help B lymphocytes and T lymphocytes (Helper T cells are target of HIV)
Suppressor T lymphocytes may damp down immune response
What are the different ways antibodies inactivate the antigen?
Neutralization, Agglutination of microbes and precipitation of dissolved antigens –> enhances phagocytosis
Activation of complement cascade –> Cell lysis
How does cytotoxic T cells work?
Cytotoxic T cell bind to the infected cell
They release perforin which damages the infected cell membrane and enzyme enteres
The infected cell is destroyed
What is immunodeficiency?
Clinical situations where the immune system is not effective enough to protect the body against infection
What are the causes of primary and secondary immunodeficiency?
Usually secondary to the effects of external factors
Some are primary immunodeficiencies caused by genetic defects in individual components of the immune system –> seen in children
What are the causes of SECONDARY OR ACQUIRED IMMUNODEFICIENCIES?
Stress
Surgery/burns
Malnutrition
Cancer – especially lymphoproliferative disease
Immunosuppressive effect of drugs inc. cancer therapy
Lymphocytes
Neutrophils
What are the characterstics of primary IMMUNODEFICIENCIES?
Very rare
Often diagnosed in early childhood but can present in
adult life
Recurrent infection often suggests immunological problem
How do you identify the underining cause of immunodeficiency?
The type of infection is a guide to underlying cause.
Laboratory tests confirm.
Are secondary immunodeficiency permanent?
No they can be transient or long lasting
Why is family history important to consider when considering a diagnosis of primary immunodeficiency?
Caused by genetic defects
What do you test for when examining someone with reccurent infection and are suspect of immunodeficiency?
You test for the levels of immunoglobulins for B cells , lymphocytes ,
neutrophils
Test of CRP if current infection to see if actually mounting an inflammatory response
Why would normal levels of immunoglobulins, lymphocytes and neutrophils be a indication of a problem for someone with a infection?
Normally these levels will be raised because of the infection. The fact that they are not means that the immune systme is not working properly
What is the role of IRAK?
is formed as part of the intracellular signalling pathway of toll like receptors (a type of PRR) when they encounter a pathogen - forms NF-kbeta which is a transcriptional factor which leads to the release of inflammatory cytokines/chemokines which leads to inflammatory and adaptive immune response
Why does deficiency in IRAK cause immunodeficiency?
Irak deficiency causes immunodeficiency because IRAK is a key component in the pathway to release of inflammatory cytokines/chemokines from the cells of the innate immune system which plays a role in the development of an adaptive and inflammatory response
How do you test for neutrophils?
Nitroblue tetrazolium test (NBT
What is the mechanism of phagocytosis in neutrophils?
NADP transport H ion
H ion travels into the cell via a specific proton channel
THis reduces the Ph within the cell making it more acidic. Therefore this allows proteolytic enzymes to enter the phagasome and destroy the pathogens
What is the defect in CHRONIC GRANULOMATOUS DISEASE ?
It is a an inherited disorder of phagocytic cells resulting in an inability to phagocytose pathogenic material
What diseases can occur in CHRONIC GRANULOMATOUS DISEASE ?
Osteomyelitis Pneumonia Swollen lymph nodes Ginigivitis Non-malignant granulomas Inflammatory bowel disease
what type of infection can indicate the person has immunodeficiency?
meningococcal meningitis
What are the 3 activating pathways for the complement pathway?
Classical pathway
Alternative pathway
MB-lectin pathway