Insufficient or overactive immune responses Flashcards
(30 cards)
what is severe combined immunodeficiency (SCID)
a rare genetic disorder that severely weakens the immune system, making infants highly susceptible to infections. It’s a type of primary immunodeficiency where the body’s ability to fight off infections is drastically reduced.
what is the cause of severe combined immunodeficiency (SCID)
caused by mutations in various genes that affect the development and function of immune cells, particularly T and B cells.
what is severe combined immunodeficiency (SCID) normally linked to and who is affected by it mostly
X linked disease
- more common in males
- females are carriers
what is virus induced immune suppression
refers to the weakening or impairment of the body’s immune system due to a viral infection. This can occur through various mechanisms, including direct viral effects on immune cells, the release of viral or host-derived soluble factors, and the induction of suppressor cells.
what is the cause of virus induced immune suppression
measels, HIV and many other viruses interfere with normal host immune system - the virus produces molecules that interfere with cell function
what does the HIV target
HIV targets and kills CD4 T cells
how does the killing of CD4 cells affect the immune system
leads to diminished levels of CD4 cells unable to provide help for antibody production an cytotoxic responses
- once amount of CD4 cells have dropped down a certain threshold the adaptive immune system stops working
how does HIV kill of CD4 cells
HIV is able to bind to CD4 T cells and replicates inside the cell
what is the humoral immune response
Humoral immunity is an adaptive immune response that involves B cell-secreted antibodies that prevent pathogens from entering host cells and tag pathogens for other immune responses to destroy them.
what are autoimmune diseases normally prevented by
by host mechanisms of immune tolerance
what are autoimmune attacks mediated by
the adaptive immune response - although the innate immune system can trigger autoimmunity or exacerbate (make the response even worse) immunity
what is immune tolerance
Immune tolerance is a state where the immune system is unresponsive to specific antigens, both self (body’s own) and non-self (foreign). This unresponsiveness prevents the immune system from attacking the body’s own tissues and organs, which would otherwise lead to autoimmune diseases.
what organ acts to get rid of autoreactive T cells
the thymus
what can lead to the failure of immune tolerance
due to genes or triggering infections
what is Rheumatoid Arthritis (RA)
an autoimmune disorder that primarily affects joints
what occurs in Rheumatoid Arthritis (RA) for the tissue to become inflamed
autoreactive T cells and B cells attack self antigens present in the joints
what is Diabetes Type 1
very specific autoimmune disease that only attacks insulin beta cells - other islets cells may escape the attack
what are allergens
the antigens that trigger allergy
what are allergens normally
harmless environmental antigens such as non toxic plants, animals or other food materials
- chemicals can also induce allergy
what is the range of allergic response
hay fever (mild) to anaphylaxis (extreme - usually due to digestible allergens)
what is anaphylaxis
a severe, potentially life-threatening allergic reaction that can occur rapidly after exposure to an allergen. It’s an overreaction of the body’s immune system, causing widespread inflammation and various symptoms.
how does an allergic response occur (peanut example)
- DC takes up peanut antigens and activates CD4 helper cell.
- CD4 T cells provide help for B cells that form IgE secreting plasma cells.
- IgE binds to Fc receptors on mast cells.
- Peanut allergens trigger (via IgE / FcR) mast cells to release histamines and other inflammatory mediators.
where does the Fc receptors bind to of the antibody
to the Fc domain/constant region
what is the function of FcR
facilitates a number of functions including:
1. phagocytosis
2. mast cell activation
