1. chemical: humoral immune response using antibodies
2. cell mediated: cells directed by immune response to attack invader

AKA immunoglobulins

they are proteins produced by the body to bind to antigens

• Y shaped
• 2 variable (light chain) regions that bind to antigens
• 1 constant "Fc" (dark chain) region that binds to host

1. Neutralization
2. Opsonization
3. Complement Activation

• 2 molecules of bound IgG
• 1 molecule of IgM

preparation of pure antibodies of single type all directed at same epitope

- normally produced artificially; not normal response but in malignancy of B cells

polyclonal is normal response

monoclonal is artificial unless B cell malignancy

IgM, IgG, IgA

IgE, IgD = less plentiful

• IgG = y (gamma)
• IgA = a (alpha)
• IgE = looks like e
• IgD = looks like d
• IgM = u (m-like)

attach by disulfide bond to joining chain

IgG; called "class switching"

- IgG antibody produced by cell has same specificity for antigen as IgM it replaces

binds to complement (fixes complement), attracts phagocytes, and opsonizes well

- penetrates tissue and crosses placenta

• higher antibody levels
• increase dproportion of IgG to other immunoglobulin isotypes
• shorter lag period
• higher affinity for antigen

Secondary response; affinity maturation 10 to 100 fold increase

IgG memory cells

In what forms does IgA occur? 

What form is secretory IgA? Where is it found?

What controls the production of IgA?

• occurs as single or paired molecules
• secretory IgA = paired; 
• found in secretions (saliva, tears, respiratory secretions, colostrum)
• IgA production controlled by T cells

1. erythroid stem cell
2. myeloid stem cell
3. lymphoid stem cell

• platelets (clotting and inflammation)
• basophils (inflammation)
• neutrophils, eosinophils and monocytes (phagocytosis)

• basophil
• neutrophil
• eosinophil
• monocyte
• lymphocyte

Polymorphonuclear leukocytes (neutrophils; PMN) ;

white blood cells able to phagocytose invaders

short lived

circulate in blood and enter tissue (gather at site of infection) = pus

WBC's 

Polymorphonuclear leukocytes (PMNs)

Which white blood cells are anti-parasitic?

How did they get their name?

• phagocytose invaders
• present the antigens to T lymphs for development of specific immunity
• "call for help" by secreting cytokines

• widely distributed in tissue in immature form
• good at presenting antigen to T lymphocytes
• immature form = phagocytoses antigen; becomes mature
• mature = stops phagocytosis and goes to lymph node to deliver antigen to T cells

come from B cell differentiation in bone marrow

they are antibody factories

each recognize a specific antigen (so many B cells that a wide range of antigens can be recognized)

membrane coated with particular antibody that cell produces

When antigen binds to antibody = stimulates cell to divide and increase in number 

called "clonal expansion"

• develop in the thymus
• control immune response by producing cytokines
• able to directly kill foreign tissue cells, virally infected cells or tumor cells
• activate phagocytic cells to destroy organisms they have ingested

activate and control immune response

respond to signal of cell presenting antigen by differentiating into: TH1 or TH2

• patrol, looking for virally infected cells or tumors
• once detected, divide and differentiate to cytotoxic T lymphocytes (able to destroy target cells)

What are natural killer cells?

What are they used to kill?

produced by cells

- bring about differentiation of cells

- cause activation of phagocytic cells and lymphocytes

- influence inflammation

- influence cell mediated response and antibody response

• usually produced in combinations
• act different on different cells
• T lymphocytes are important source

• antigens must be presented
• Major Histocompatibility complex class I an II play big role

MHC I = CD 8 

MHC II = CD 4

1. bone marrow (produces precursor cells to all immune cells; also where B cells mature)
2. Thymus (responsible for maturation of T lymphocytes)