3. Intro to Immunology

Question 1

where are B cells developed?

Answer 1

bone marrow

Question 2

where are T cells developed?

Answer 2

thymus

Question 3

are T cells or B cells involved in antibody production and memory?

Answer 3

B cells

Question 4

MHC1-self peptide

Answer 4

usually lots of MHC1 self peptide and minimal NK cell-activating ligands

when stressed/abnormal, ratio resverses

mediate NK cells acti on(perforins/granzymes released if activated)

Question 5

what is the humoral arm of the innate immune system?

Answer 5

complement

Question 6

main functions of complement

Answer 6

• opsonization (C3b can bind to surface of pathogens and enhance phagocytosis, “tasty sprinkles”
• inflammation (C3a effects chemotaxis and mast cell degranulation)
• cell lysis (complement components build a tunnel through the pathogen cell membrane = MAC the membrane attack complex)

Question 7

3 major pathways of complement

Answer 7

1. classical (requires antibody/antigen complex, specific immune response and part of adaptive system)
2. alternate pathway (can be triggered directly by pathogens or other substances)
3. lectin pathway (triggered by microbial carbohydrates)

Question 8

what does it mean that T cells are involved in cellular immunity (opposed to humoral immunity)?

Answer 8

cell needs to be physically present to help

Question 9

what are cytotoxic T cells?

Answer 9

CD8 cells

involved in direct killing of infected cells

• detect nonself antigen being presented by infected cell (requires a second messenger = SAFEGUARD)
• effects = perforin/granzyme, FAS ligand, or tissue damage

Question 10

helper T cells

Answer 10

CD4 direct other immune system elements

2 major subtypes:

1. Th1 vs bacteria (help T cells and macrophages)
2. Th2 vs parasites (help B cells, eosinophils)

Question 11

B cells are characterized by the presence of what?

Answer 11

BCR (b-cell receptor)

• a membrane bound antibody
• targeted at a relative specific antigen
• can be secreted (antibody)

Question 12

B cell subtypes

Answer 12

• naive B cells (mature, no antigen exposure yet - express surface IgM/IgD…when BCR binds antigen, divides and differentiates into plasma cen memory cells)
• plasma cells (post exposure, large amounts of antibody production, apoptosis after antigens cleared)
• memory cells (long lived)
• antigen-presenting cells

Question 13

MHC

Answer 13

major histocompatibility complex = main mechanism to present antigens

family of cell -surface proteins:

• MHC class 1: all nucleated cells (present whatever is in the cell, mostly self-antigens in a normal cell…goof for intracellular infections or tumors, problem in transplant and some autoimmune disorders)
• MHC class 2: antigen presenting cells (together with antigens will activate helper T cells, present phagocytized particles)

Question 14

cytokines

Answer 14

proteins secreted into blood and extracellular fluid

functions:

• communicate b/w cells and envt
• each has several functions
• autocrine (eg T cell prolif after exposure to MHC2
• paracrine (eg blood clotting, scar formation)
• endocrine
• innate immunity (induce inflammation, inhibit viral replication, eg IL1 and chemokines)
• adaptive immunology (lymphocyte prolif/maturation, eg IL2, IL4, IFN-gamma and some prevent positive feedback cycle by limiting inalmmatory processes)
• hematopoiesis (increase WBC production, colony-stimulating factors that drive WBC production in the marrow)