Unit 3 Chapter 47 Animal defenses against infection
Humoral response: plasma cells are effector cells, B cells, antibodies
Cell mediated response: cytotoxic T cells are effector cells
Both have: helper T cells and cytokines, antigen-presenting cells, memory cells
Antigen receptors embedded in their plasma membranes enable specific B cells and T cells
to recognize and bind to a specific antigen or antigen fragment. After encountering an
antigen or antigen fragment it recognizes, the lymphocyte becomes activated, triggering a
response called clonal selection (sometimes called clonal expansion). Clonal selection
produces effector cells and memory cells of the activated lymphocyte.
Plasma cells are the effector cells of the humoral response; they secrete antibodies that
neutralize or tag the foreign pathogen for destruction. Active cytotoxic T cells are the
effector cells of the cell-mediated response; they kill infected cells displaying the antigen.
Activated helper T cells stimulate the effector cells of both responses with cytokines.
The memory cells produced by clonal selection contribute to immunological memory.
Memory B cells, memory cytotoxic T cells, and memory helper T cells increase the speed and
effectiveness of the immune response to an antigen the body has encountered before.
Cytotoxic T cells and cell-mediated response
B cells and humoral immunity
, Plasma cells need a few days to produce antibodies
Plasma cell lifespan 4-5 days, memory cell lifespan 10 years
Key terms
B cells and T cells
Immune system cells and their function
Humoral response: plasma cells are effector cells, B cells, antibodies
Cell mediated response: cytotoxic T cells are effector cells
Both have: helper T cells and cytokines, antigen-presenting cells, memory cells
Antigen receptors embedded in their plasma membranes enable specific B cells and T cells
to recognize and bind to a specific antigen or antigen fragment. After encountering an
antigen or antigen fragment it recognizes, the lymphocyte becomes activated, triggering a
response called clonal selection (sometimes called clonal expansion). Clonal selection
produces effector cells and memory cells of the activated lymphocyte.
Plasma cells are the effector cells of the humoral response; they secrete antibodies that
neutralize or tag the foreign pathogen for destruction. Active cytotoxic T cells are the
effector cells of the cell-mediated response; they kill infected cells displaying the antigen.
Activated helper T cells stimulate the effector cells of both responses with cytokines.
The memory cells produced by clonal selection contribute to immunological memory.
Memory B cells, memory cytotoxic T cells, and memory helper T cells increase the speed and
effectiveness of the immune response to an antigen the body has encountered before.
Cytotoxic T cells and cell-mediated response
B cells and humoral immunity
, Plasma cells need a few days to produce antibodies
Plasma cell lifespan 4-5 days, memory cell lifespan 10 years
Key terms
B cells and T cells
Immune system cells and their function
