Class 2 Flashcards
In order for T-cells to recognize and respond to an antigen, it must be presented by ________________________________.
another cell or an antibody.
For T-cells to recognize & respond to an antigen, it must be presented by another cell or antibody. It must be coded by Major Histocompatibility Complex (MHC) = ___________________________________________________. In humans, they are often called ____________________________.
• a group of genes on chromosome 6 that determine tissue & blood compatibility.
• Human Leukocyte Antigens (HLA).
What are the 2 classes of HLA?
-Class I are on all cell surfaces
-Class II are on immune system cells
HLA are key factors in determining self from non-self. However, they can also identify self-targets as well as…
-They lead to T-cells attacking, or ignoring an antigen
-They are genetically determined self-markers
T-cells will attack or ignore an antigen based on the ______.
Human Leukocyte Antigens (HLA)
Immunity is acquired in four ways and can be active or passive. What is the difference between active and passive immunity?
• active = body develops its own antibodies (B-cells run into antigens & start pumping out antigens)
• passive = body is given antibodies
What is the 4 ways immunity is acquired?
1) Active natural immunity – develops through direct exposure to antigen
2) Active artificial immunity – develops when body is purposefully introduced to antigen (ex. vaccines)
3) Passive immunity – passed from mother to fetus
4) Passive artificial immunity – injected from one system to another
What is Immunologic self-tolerance?
Ability to distinguish between self & non-self antigens.
In a healthy individual, mechanisms are put in place to eliminate T or B-cells that fail to differentiate between two antigens. What happens when these mechanisms fail?
When these mechanisms fail, autoimmune disorders arise.
What is Auto-immunity?
Mounting of an immune response against body’s own tissues.
Auto-immunity is the mounting of an immune response against the body’s own tissues. What are the reasons this happens?
➢ Attacked body tissue may have similar characteristics to a microbe the immune system has just battled.
➢ Some HLA inheritance corresponds to activation of autoimmune disease.
➢ Sometimes there is an over response of immune activities.
➢ Sometimes there is a reduced T-cell suppressor response.
In Rheumatoid Arthritis (RA), there is an autoimmune response to self-IgG. The resulting body is called ____________________.
Rheumatoid factor
What is rheumatoid arthritis?
• RA involves immune system attack on synovial membranes of joints, eventually leading to bone erosion & joint deformities.
- Tender, warm, painful joints; joint stiffness following inactivity
What is multiple sclerosis?
- Auto-antibodies create an immune attack on self-myelin in CNS’s neurons (specifically the neuroglial cell: Oligodendrocytes).
- Depending on what region of brain is affected, there will be varying outcomes.
In Multiple Sclerosis (MS), auto-antibodies create an immune attack on self-myelin in the CNS’s neurons (specifically the neuroglial cell: ___________________).
Oligodendrocytes
What is an autoimmune disease where acetylcholine receptors at neuromuscular junction are destroyed by immune cells after having been bonded by auto antibodies.
Myasthenia Gravis
T/F Auto antibodies bind with self molecules to create immune complexes
True
T/F In RA and SLE, such immune complexes travel in bloodstream to target tissues like joints. By gathering in these tissues, immune complexes subject them to intense tissue destruction from immune system responses & their sequelae.
True
T/F There may be mistaken targeting of self cells as dangerous
*True
Since some self cells (ex. virus infected cells, or cancerous cells) are identified & presented for destruction, misidentification is possible. This has been found to occur in reactions to drugs and viruses that appear to have altered cellular markers in affected person’s body.
T/F Auto-immunity can have elements of hypersensitivity reactions
*True
Immune complexes attract inflammatory & cytotoxic reactions where tissue damage is result of intense responses related to complement activation & killer cell activity. This component of diseases like RA & SLE is type III hypersensitivity reaction. Response is more destructive than stimulus warrants. In examples stimulus is an autoimmune one.
T/F Autoimmune diseases are more common in women than men?
Autoimmune diseases are more common in women then men, not quite understood why but possible that it’s a hormonal component.
Treatment tends to involve use of corticosteroids & immunosuppressive drugs to try to counter or reduce _______________________________.
cellular damage being caused by immune system response.