Slide 1
Immune memory can change a later encounter
Adaptive immunity can retain a record of an earlier target. Memory cells help the body respond differently when that target appears again.
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The record is biological rather than conscious: populations of cells persist with recognition properties shaped by the earlier response. No memory of feeling ill is required.
Slide 2
The first response leaves some cells behind
A first encounter activates and expands suitable immune cells. Some descendants remain after the immediate response has declined.
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Antibody levels and memory-cell populations are related but different measurements. A falling antibody concentration does not by itself describe every aspect of the retained response.
Slide 3
Vaccination can prepare recognition before the full disease
Vaccination presents a target or instructions for producing it so the immune system can prepare a response without the full natural disease.
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Different vaccine designs deliver different forms of antigen. Their shared purpose is preparation, while the strength, duration and type of protection depend on the vaccine and pathogen.
Slide 4
Passive immunity supplies antibodies made elsewhere
Passive immunity supplies antibodies made elsewhere. It can provide protection without requiring the recipient to build the same response first.
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Maternal antibodies and some antibody-containing medical products are examples. This protection generally wanes as those antibodies disappear, unlike a response maintained by the recipient’s own memory cells.
Slide 5
Protection still depends on targets and people
Immune memory is directed toward recognized targets. Changes in a pathogen or differences among people can influence how useful that memory remains.
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Protection against infection and protection against severe illness are distinct outcomes. A response may still reduce disease severity even when it does not prevent every infection.
Sources
- Principles of Vaccination
CDC Pink Book
- Immunity Types
CDC