I looked, and there was a pale green horse. Its rider was named Death, and Hades accompanied him. They were given authority over a quarter of the earth, to kill with sword, famine, and plague…

-- Revelation 6

Genghis Kahn

1162 – 1227

Claim to fame???

Immunity How do you defend yourself from

disease?1. Surficial barriers

2. Innate responses

3. Adaptive responses

Questions to ponder… What does it mean to be “sick”? What steps are involved in removing

infection? How can my body tell what is ‘me’ and

what is not?

Barriers Against Infectious Agents

Behavioral

Barriers Against Infectious Agents

Behavioral

Barriers Against Infectious Agents

Intact skin

Barriers Against Infectious Agents

Intact skin and mucous

membranes

Barriers Against Infectious Agents

Intact skin and mucous

membranes

Normal bacterial flora

Innate/Nonspecific Responses

Phagocytosis

Innate/Nonspecific Responses

Phagocytosis

Fever

Increase rate of response in host

Decrease rate of growth in bug

Innate/Nonspecific Responses

Phagocytosis

Fever

Natural killer cells

Innate/Nonspecific Responses

Phagocytosis

Fever

Natural killer cells

Complement System

Plasma proteins that take part in both specific and nonspecific response

Activation of one triggers cascade of reactions that activate others

Complement Attack Complexes

antibodyactivated

complement

bacterial pathogen

lipid bilayer of pathogen

Activation Cascade Reactions

Formation of Attack Complexes

Lysis of Target

Phagocytosis

Fever

Natural killer cells

Compliment system

Inflammation

Innate/Nonspecific Responses

Inflammation

Mast cells release histamine Capillaries dilate and leak so that...

Complement proteins attack bacteria

White cells attack invaders and clean up

Features of Adaptive Immune Responses

Self/nonself recognition

Specificity

Diversity

Memory

Stimulated B or T cells

produce

Memory cells - set

aside for future use

Effector cells – plasma

cell that engages the

current threat

Clone of memory cells Clone of plasma cells

Antibody Structure

Consists of four polypeptide chains

Certain parts of each chain are variable; impart antigen specificity

antigen binding site

constant region

variable region

Adaptive Immunity 1 – The Humoral Response

LE 43-19

Viral neutralization(blocks binding to host

and opsonization increasesphagocytosis)

Agglutination ofantigen-bearing particles,

such as microbes

Precipitation ofsoluble antigens

Activation of complement systemand pore formation

Binding of antibodies to antigensinactivates antigens by

Bacteria

Solubleantigens

MAC

Complement proteins

Foreign cellPore

Virus

Bacterium

Enhances

Phagocytosis

Macrophage

Cell lysis

Leads to

Adaptive Immunity 2 – Cell Mediated Immunity