Chapter 16

• Response against antigen circulating in body fluids
• Mediated by antibodies produced by B lymphocytes

• Effective against intracellular pathogens and tumor cells
• Mediated mainly by T lymphocytes (cytotoxic T cells)

• Acquired during life time on exposure of an antigen
• Has memory
• Slower immune response
• Mediated by lymphocytes

• A foreign substances that induces immune response
• Bind to antibody (or T cells) produced against it

Portein, glycoprotein, polysaccharide, nucleic acid in nature

• Cell wall componenets
• Flagella
• Frimbrae of bacteria
• Spike or protein coat of viruses
• Pollen
• Fungal spores
• Metals
• Certain food items
• Drugs

• Antigens present on surfaces of our own cells
• Not attacked by immune system

Antigens present on microbes, any foreign cells, or foreign material (food, drugs, spores, pollens, ect.)

• Present on the microbes taht are circulating in body fluids
• (outside the cells)

• Present on microbes present inside cells
• Tumor cells also carry these
• Present on grafted tissue

3-D Part of an antigen that actually initiates antibody production

• Protein produced by B lymphocytes in reponse to specific epitope
• AKA immunoglobulins (IG)

• 2 Heavy and 2 Light chains linked by disulfide bridges (hinge region)
• Antigen-binding site (epitope)- has variable and constant region

• Monomer
• 80% of serum antibodies
• Complement activation
• Opsonization, neutralize toxins & viruses
• Crosses placenta: protects fetus

• Pentamer: Larger antibody
• Complement activation
• Agglutinates microbes
• Neutralization of microbes
• First Ab produced in response to infection: a high concentration in serum indicates current infection