40 Questions
What type of immunity is produced by the individual after initial exposure to an antigen or after immunization?
Active immunity
What is the duration of passive immunity?
Temporary
What is the primary response during the initial exposure to an antigen?
Production of IgM antibodies
What is the main reason for the rapidity of the secondary response?
Presence of memory cells
What is the function of T lymphocytes in the immune response?
Function in the activation of other T & B cells
What is the characteristic of the IgG response in the secondary response?
Considerably greater than the IgM response
What occurs during the latent period or lag phase of the primary response?
B cell differentiation
What is the type of response that involves the host's immune response?
Active immunity
What is the term used to describe the manifestation of allergic conditions in a family?
Atopic hypersensitivity reaction
What type of hypersensitivity reaction occurs when an antibody attaches directly to an antigen in the target tissue?
Type II hypersensitivity
What is the result of the interaction between IgG antibodies and the antigen in Type II hypersensitivity?
Destruction of the cell
What is an example of Type II hypersensitivity?
Response to an incompatible blood transfusion
What is the term used to describe the phenomenon where cell membranes sometimes lose their 'self' identity and become alien, leading to an immune response against self?
Unknown mechanism
What type of reaction occurs in individuals with type A blood when they receive type B blood?
Type II hypersensitivity
What is the result of the activation of complement activation in Type II hypersensitivity?
Release of cytolytic enzymes
Why do people with type A blood have anti-B antibodies in their blood?
Because they have type A antigens on their red blood cells
What percentage of white blood cells are lymphocytes?
25-35%
Where do pre-T cells migrate to and divide into T cells?
Thymus
What is the main function of regulatory cells in the immune response?
To orchestrate and control the immune response
What percentage of lymphocytes are B cells?
10-20%
What is the result of lymphocytes being stimulated by their antigen?
They acquire a memory response
What is the primary function of effector cells?
To attack the antigen and destroy it
What type of immunity is acquired through previous exposures to infectious and other foreign antigens?
Adaptive immunity
What is the process by which lymphocytes mature into distinct types?
Differentiation
What is the result of adding type B blood to a type A blood recipient?
Hemolysis
What is the mechanism of action of autoimmune antibodies in myasthenia gravis?
Blocking acetylcholine receptors
What is the outcome of the combination of antigen and antibody in immune complex formation?
Inflammation and tissue destruction
What is the location where immune complexes are deposited in Glomerulonephritis?
Glomerular capillaries of the kidneys
What is the term for the systemic reaction that occurs when immune complexes deposit in many tissues?
Serum sickness
What is the role of immune complexes in autoimmune diseases?
They cause inflammation and tissue destruction
What is the target of autoimmune antibodies in Rheumatoid arthritis and SLE?
Collagen and cellular DNA
What is the outcome of the activation of complement in immune complex formation?
Inflammation and tissue destruction
What is the approximate frequency of selective IgA deficiency in the population?
1 in 400
What is a characteristic feature of Di George Syndrome?
Low levels of calcium in the blood
What is the underlying cause of SCIDS?
Absence of a common stem cell for all white blood cells
What is the typical outcome for infants with SCIDs caused by reticular dysgenesis?
They die in utero or very soon after birth
What is the goal of treatment for SCIDS?
To introduce healthy stem cells into the bone marrow
What is a common infection associated with selective IgA deficiency?
Recurrent otitis media
What is the genetic basis of Di George Syndrome?
Deletions on chromosome 22
What is a characteristic feature of infants with SCIDS?
They die in utero or very soon after birth
Study Notes
Immune Response
- Antigen-antibody reaction can destroy RBCs in type A blood if type B blood from a donor is added, resulting in hemolysis
- IgG antibodies can bind to target-cell membrane receptors, blocking receptor function, as seen in myasthenia gravis
Cytotoxic Reaction
- Formation of immune complexes, which can cause inflammation and tissue destruction, is the cause of most autoimmune diseases
- Examples of diseases caused by immune complexes include:
- Glomerulonephritis
- Rheumatoid arthritis
- SLE
- Serum sickness
Immunity
- Immunity can be either active or passive, depending on whether the individual produces antibodies or T cells, or receives them from a donor
- Active immunity is a long-lived immunity produced by the individual after exposure to an antigen or immunization
- Passive immunity is temporary and does not provide a memory response
Primary and Secondary Response
- Primary response:
- Initial exposure to an antigen
- Latent period or lag phase
- B cell differentiation occurs
- After 5-7 days, IgM antibody is detected
- IgG response follows
- Secondary response:
- More rapid response
- Larger amounts of antibody are produced
- Rapidity is due to the presence of memory cells
T Lymphocytes
- Function in the activation of other T and B cells
- Control viral infection, rejection of foreign tissue grafts, and delayed hypersensitivity responses
Hypersensitivity Reactions
- Type 1 reactions:
- Allergic rhinitis (hay fever)
- Hives
- Some cases of asthma
- Tendency towards allergic conditions is inherited
- Type 2 hypersensitivity (cytotoxic hypersensitivity):
- Antibody attaches directly to an antigen on a cell membrane
- Example: response to an incompatible blood transfusion
Adaptive Immunity
- Immunity acquired through previous exposures to infectious and foreign antigens
- Components of the adaptive immune system include:
- T and B cell lymphocytes
- Their products
Lymphocytes
- Primary cells of the specific immune system
- Represent 25-35% of WBC
- 99% of cells reside in the lymph
- Derived from stem cells
- Mature into distinct types:
- T cells (involved in cell-mediated immunity)
- B cells (produce antibodies)
Immune Deficiencies
- Selective IgA deficiency:
- Individuals are unable to produce IgA but can produce other immunoglobulins
- Frequently present with chronic intestinal candidiasis
- Occurs in about 1 in 400
- Di George Syndrome:
- Complete or partial absence of T-cell immunity
- Characterized by severe congenital structural defects of the heart and low levels of calcium
- May result in seizures
- Exhibits a congenital aplasia or hypoplasia due to deletions on chromosome 22
- SCIDS (Severe Combined Immunodeficiency Syndrome):
- Absence of a common stem cell for all white blood cells
- T-cells, B-cells, and phagocytic cells never develop
- Most children with SCID die in utero or soon after birth
- Rare, with only about 40 cases reported each year
- Genetic mutation leading to absence of all immune function
- Treatment: bone marrow transplantation or stem cell transplantation
Learn about the 3rd line of defense in the immune system, adaptive immunity, and its components, including T and B cell lymphocytes. Understand how regulatory cells control the immune response.
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