The Immune System
Mariela & Julia
Basic Immune Vocab
Leukocyte: white blood cell
Lymphocyte: white blood cell with a large spherical
nucleus surrounded by a smooth cytoplasm.
Pathogen: invading microorganisms and viruses (egcold/flu)
Antigen: foreign molecules that stimulate a response
from the immune system (eg-allergies to pollen)
Antibodies: defend against infection in body fluids
Cytokines: cell signaling protein molecules
Red blood cell, platelet, and white blood
cell.
Innate and Acquired
Innate immunity: involves recognition of traits shared
Immunity
by a broad range of pathogens using a set of
receptors, and results in a rapid response.
Barrier defenses (skin, mucous membranes secretions)
Internal defenses: phagocytic cells, ain't microbial proteins,
inflammatory response, natural killer cells
Acquired immunity: recognizes traits specific to
particular pathogens using receptors, resulting in a
slower response.
Humoral response: antibodies defend against infects in body fluids
Cell-mediated response: cytotoxic lymphocytes defend against
infection in body cells
Try THIS!!!
Although pus is often seen simply as a sign of a
infection, it also an indicator of immune defenses in
action! Explain.
Phagocytosis
Chap 43
Campbell!
Phagocytic white blood cells
Innate Immunity
Neutrophils: ingest/destroy microbes via phagocytosis
Monocytes: go into tissues and develop into
phagocytic cells.
Eosinophils: defend against parasites by secreting
hydrolytic enzymes.
Antimicrobial Proteins
Interferon: provide innate defense by making cells
produce substances to inhibit viral infection
Inflammatory Response
Triggered by injury to tissue. Histamines are released
to trigger the dilation of the capillaries, which allows
clotting agents.
Natural Killer Cells (NK cells)
All vertebrates have two types of white blood
cells (lymphocytes)!!
Acquired Immunity
B lymphocytes (B cells): reproduce in the bone
marrow
T lymphocytes (T cells): reproduce in the
thymus (butterfly shaped gland at the base of
your neck)
B or T cell activation occurs when an antigen
binds to the B or T cell.
Clonal selection: B cell activation is enhanced
by cytokines, allowing the lymphocyte to form
two clones, thus creating a multitude of cells
specific to fighting the particular antigen.
Effector cells fight the antigen.
Memory cells live longer and bear receptors for
Pollen (possible antigen)
B & T cells
B cell receptors bind to intact antigens.
T cell receptors bind to antigens on antigen presenting cells (AHCs)
on their major histocompatibilty complex molecules (MHCs).
MHCs: proteins that are the product of gene groups. Class I MHCs
are on all body cells except for red blood cells. Class II MHCs are
made by B cells, macrophages, and dendritic (branching neuron)
cells.
Each B or T cell responds to only one antigen.
Primary immune response (the pilot episode): body exposed to
antigen, lymphocyte activated.
Secondary immune response (season two): same antigen is
encountered again!!! It is faster and stronger!!!
TRY THIS!!!
Explain the two advantages of having memory
cells when a pathogen is encountered for a
second time!