Immunology Lec 3 Flashcards
Lecture 3:
What are the primary lymphoid tissues and their functions?
Bone Marrow: Produces blood cells including B cells.
Thymus: Site for T cell maturation.
What are the secondary lymphoid tissues and their functions?
Spleen and lymph nodes; sites for immune responses.
Describe the typical structure of immunoglobulin molecules.
Immunoglobulin molecules have two heavy chains and two light chains joined by disulphide bonds, with variable and constant regions.
What are the functions of IgM?
IgM is the first antibody produced, activates complement, and is too large to cross the placenta.
What role does IgG play in the immune system?
IgG is the most abundant immunoglobulin, can cross the placenta, and is involved in opsonization and complement activation.
What are the primary and secondary immune responses?
Primary Response: Slow, production of IgM followed by IgG.
Secondary Response: Rapid, longer-lasting, mainly IgG, with higher affinity due to affinity maturation.
What are the two types of B cell activation?
T-Independent Activation: Bacterial endotoxins trigger IgM production.
T-Dependent Activation: Requires help from T-helper cells for B cell proliferation and antibody secretion leading to memory formation.
How do B lymphocytes differ from T lymphocytes?
B Lymphocytes: Produce antibodies, mainly effective against extracellular infections.
T Lymphocytes: Recognize antigens via T-cell receptors, involved in intracellular infection response.
What is class switching in immunoglobulins?
Class switching is the change of heavy chains in immunoglobulins while maintaining antigen specificity.
What is somatic hypermutation and its significance?
Somatic hypermutation alters variable regions of immunoglobulins to improve antigen binding affinity. (AVR/IABA)
Name and describe the specific functions of IgE.
IgE is involved in allergic responses and defense against parasites.
Where is IgA primarily found and what is its function?
IgA is found in mucosal areas and is involved in mucosal immunity.
What are the roles of immunoglobulins in the immune system?
Immunoglobulins act as adapter molecules that can activate complement, mediate phagocytosis, and trigger allergic reactions.
