Immunity, Immune System and Immune Response. Envr 421 Mark D. Sobsey. Antigens. Any foreign substance that elicits an immune response when introduced into the tissues of a susceptible animal and capable of combining with the specific antibodies formed. Generally high molecular weight
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Immunity, Immune System and Immune Response
Mark D. Sobsey
Any foreign substance that elicits an immune response when introduced into the tissues of a susceptible animal and capable of combining with the specific antibodies formed.
Generally high molecular weight
Typically, proteins or polysaccharides.
Polypeptides, lipids, nucleic acids and many other materials also can also function as antigens
Microbes are antigenic and they contain and produce many antigens
Antigens have specific sites that bind to antibodies called “epitopes”
Made up of two cellular systems:
Biological Components of Human Immune System
(Red blood cell)
(Non-specific cells responding to antgens and allergens)
Clonal Selection of B Cells is Due to Antigenic Stimulation
Produces secreted antibodies (proteins)
IgG antibody molecule
Role of Immunity in InfectionsLocalized Infections:
Role of Immunity in Infections:Generalized/Systemic/Disseminated Infections
Major change in virus genetic composition by gene substitution or replacement (e.g., reassortment)
Minor changes in virus genetic composition, often by mutation involving specific codons in existing genes (point mutations)
But, a single point mutation can greatly alter microbial virulence!
Role of Selection of New Microbial Strains in Susceptibility to Infection and Illness: Antigenic Shift and Drift