Immunology

Purpose of the immune system: –Discriminate self from non-self Non-self –Antigens Immunity: –All mechanisms used by the host to protect itself and fight non-self

Non-Self - Antigens Anything that can react with the participants of the immune system –Ex. antibodies Epitope: Characteristic of the antigen which allows its recognition as being non-self –Ex. Lipids, proteins, lipopolysaccharides

The Antigen Virus=Antigen Epitopes

Immunological Diagnostic Methods Determine the presence of an antigen: An organism A protein A toxin An antibody –ELISA method to determine quantity –Immunochromatography (Rapid tests)

ELISA Used to detect the presence of antigens or antibodies –High sensitivity –Quantitative

ELISA Method ENZENZENZ ENZENZ ENZ ENZ ENZ ENZ ENZ Serum (source of Ag) is added to plastic wells Antigen Present Antigen Absent Blocking agent added Ag Ab against Ag is added Wash Detecting Ab added Wash Substrate added

Interpretation of Results Serums of patients tested for the presence of HIV –1 o Ab anti-HIV from mouse –2 o Ab anti-Ab of mouse Conclusions –Patients 1 & 3 are positive for HIV –Patient 3 has a higher titer –Patient 2 is negative for HIV 1/2 1/4 1/8 1/16 1/32 1/64 1/128 Control serums + — 1/8

Immunochromatography Method 9

Interpretation 10 Positive Negative Invalid