lecture saum

Question 1

adaptive immunity factors

Answer 1

Specificity Billions of
lymphocytes recognizing different
antigens
* Lymphocytes with receptors that
recognize the specific Ag will
proliferate (clonal expansion or
clonal selection)
* The adaptive immune system
acquires immunological memory
towards foreign Ag acquired
or protective immunity

Question 2

b lymphotcytes

Answer 2

Membrane bound on B cell surface function as antigen
receptors Initiate B cell activation proliferation and
differentiation of antigen-specific B cells plasma cells
secretion of soluble form of the antibody (same specificity as
the mb bound)

Question 3

antibody functions

Answer 3

Basic Functions
* Binding antigens
* Activate complement system
* Neutralization:
Binding and neutralizing bacterial toxins
Inhibiting bacterial access to host cells
Inhibiting viral entry into host cells
* Enhancing phagocytosis of pathogens
(opsonization

Question 4

t cell

Answer 4

• Carry out cell-mediated immunity
• Do not secrete antibodies; directly bind to targets
• Killer T cells release chemicals that destroy
  targeted cells
• Clonal and antigen specific; acquire
  receptors/mature in the thymus
• T cells are activated for foreign attack only when
  the attack is on the surface of a cell that carries
  foreign antigens presented on self-antigens
• T-cell receptor (antigen
  receptor) peptide
  fragments (antigen) bound to
  self proteins called Major
  Histocompatibility Complex
  (MHC) displayed on
  surface of APCs

Question 5

CD4 cells

Answer 5

(mostly helper T cells: Th)
* Modulate activities of other immune cells and secrete chemicals
that amplify the activity of other immune cells

Question 6

CD8 cells (

Answer 6

(cytotoxic, or killer T cells: Tc)
* Destroy host cells harboring anything foreign (viral infected cell;
cancer cell)
* Bind to the viral antigen and self-antigen on the surface of the
infected cell
* May kill cell directly or through enzymes that cause the cell to
self-destruct