1. Phagocytic Cells = cells that
____________________ =any foreign molecule recognized by a lymphocyte (B or T cell)
a) most are proteins or polysaccharides
b) may protrude from microbe membrane
c) eptiope = tiny part the lymphocyte binds

2. = major histocompatibility complex
________________that code for MHC molecules
All are :
Class I MHC display ________________ synthesized within the cell (cancer/virus)
found on most body cells
Class II MHC display peptides that are:
found on phagocytic cells & B cells

3. * Helper–T cells Type of T cell that binds to :
(Class II MHC molecules)
Helps promote :
Promote Humoral (B-cell) response by :
Promote cell mediated-response by:

4. External Defenses 1) Skin…waterproof layer dead cells
2) Linings of body tubes/cavities a) b) c) d)
3) Neutral/beneficial bacteria population

5. Internal Defenses I. present at birth, always present II.
activated by microbes/antigens
a) Require self-recognition
(membrane proteins)
b) only present in Vertebrates

6. I. Innate Immunity A) Antimicrobial proteins B) inflammatory response
C) Systemic response
D) Phagocytic Cells

7. A) Antimicrobial Proteins
1) interferon ά and β
secreted by virus-infected cells
help neighboring cells inhibit viral reproduction
2) complement system = 30 serum proteins
a. microbe presence triggers cascade
b. cascade activates complement system
c. system causes microbe to lyse
& triggers inflammation
(may also be activated by antibodies*)

8. B) Inflammation Triggered by chemical signals like histamine
Complement system, allergen, antigen or injury cause mast cells to release histamine
Histamine dilates capillaries, lets out more clotting elements, anti-microbial proteins
___________________ released by capillary attract phagocytes
Clotting blocks spread of microbes

9. C) Systemic Response Widespread response Increased WBC production
Fever – ___________________________
Septic shock – bacterial infection causes high fever low bp may cause death

10. D) Phagocytic cells (4 types)
1) neutrophils –
2) macrophages –
3) eosinophils –
4) dentritic cells – activate acquired immunity a) b) c) d) e)

13. II aquired/adaptive immunity
A) Humoral Response =
B) Cell Mediated Response =
infected cells
Cancer cells
Transplanted cells

14. Antibodies Proteins secreted by differentiated B-cells (plasma cells)
Bind to specific antigen
Also called Immunoglobulins (Ig)
1) IgG –
2) IgA –
3) IgE –

15. Humoral Response = B cells put antibodies in fluid (humor)
1. B cell receptor binds to a Polysaccharide or protein on microbe, pollen or transplanted cell
2. B cell takes in antigen and presents it on MHC surface protein to attract :
3. Helper T binds to MHC-antigen complex and begins secreting :
4. cytokines induce mitosis in B cell to produce a. b.

16. Plasma cells make antibodies specific to the antigen that their parent B-cell bound
1.bind & clump viruses/bacteria
2. percipitate antigens dissolved in fluid
3. activate complement proteins
Memory B-cells stay in blood stream ready to become activated in :

17. Cell Mediated Response =fights cancer, infected cells, transplant cells
1. Class I MHC molecule displays antigens
that are :
2. Cytotoxic Tcells bind to MHC-antigen complex (CD8 protein ropes them together)
3. Binding makes cytotoxic Tcell secrete: a.
(protein, makes holes in membrane) b. c.

18. More on Helper T Cells Helper T cells Activate by 1. binding
on dendritic cells, macrophages, or B-cells
2. Makes :
a. cytotoxic T cells to become active
b. B cells to begin clonal selection…..
mitosis to produce :

19. Helper T clonal selection
Activated helper T does mitosis
1 clone divides to make many:
The other divides to make :

20. Lymphocyte receptor diversity
1 million diff. B cells….10 million diff. T cells
When leukocytes differentiate into lymphocytes
1. Recombinase enzymes link :
2. DNA between selected segments is deleted
3. receptor gene made of V seg + J seg + an
intron and a constant segment.
4. that protein makes the 5.