Medical Micro Lecture #1

Immune System

functions to eliminate infectious agents, toxins, and malignancies

Self and Non-self

a chief function of the immune system is to distinguish between ____ and _______

Immunity

the ability to respond to foreign substances including molecules and microbes

Immune Response

the body's response to a foreign substance involving cells and molecules of the immune system reacting with the substance to render it harmless

Innate

immune system that acts as effector molecules to recognize broad structural motifs that are highly conserved in microbial species

True

T/F: the innate immune system contains anatomic and physiologic barriers, inflammatory mediators, and cellular components

Adaptive

immune system that recognizes foreign substances via receptors for them on lymphocytes

B Lymphocytes (B Cells)

possess surface immunoglobulins that react with antigens to activate the differentiation into plasma cells

Plasma Cells

secrete immunoglobulin molecules or antibodies into the cellular environment

Humoral Immune Response

made up of B cells, plasma cells, and antibodies

Epitope (Determinant Group)

the specific portion of the antigen that reacts with a receptor

False

T/F: a single immunoglobin molecule on the surface of a B cell and interact with multiple epitopes

Antigen Presenting Cell (APC)

a cell that displays foreign antigens complexed with major histocompatibility complexes on their surface plasma membranes, so it can be recognized by other cells

False

T/F: T cell receptors (TCRs) are secreted

Cellular Immune Response

the immune system's third line of defense, involving the attack of pathogens by T cells

Major Histocompatibility Complex (MHC)

a gene region that codes for human leukocyte antigens (HLAs)

Before

the generation of antigen binding specificity of T and B cells occurs __________ (before/after) antigen exposure through DNA rearrangement

Clonal Selection

antigens bind to specific receptors, causing a fraction of lymphocytes to clone themselves

Immunodeficiency

absence of one or more elements of the immune system, congenital or acquired during life

Dysfunction

an immune response detrimental to the host

Hematopoieseis

the generation of all blood cells

Pluripotent

cells that are capable of differentiating into any kind of cell (stem cells)

Bone Marrow; Liver

cells of the immune system are derived from the _____ in adults and the _____ in the fetus

True

T/F: the sternum, vertebrae, iliac bones and ribs are the main sites of hematopoiesis

False

T/F: leukocytes are only involved in adaptive immunity

Neutrophils

most abundant white blood cell and the first to arrive at inflammation

Phagocytes

neutrophils are _________ since they ingest and destroy foreign protein and bacteria

Eosinophils

polymorphonuclear granulocytes that mainly defend against parasites

Allergies or Parasitic Infestation

eosinophilia is associated with _______ or ___________

IgE

eosinophils have _____ antibodies that react with surface receptors to initiate degranulation

Phagocytic

extruded granules are a useful alternative for killing large extracellular pathogens that cannot be ingested by _____________ cells

Basophils

polymorphonuclear granulocytes that contain IgE antibodies responsible for immediate hypersensitivity and are found in the blood

Mast Cells

polymorphonuclear granulocytes that contain IgE antibodies responsible for immediate hypersensitivity and are found in the soft tissue beneath the epithelial linings of the skin and respiratory tracts, intestinal, and genitourinary tracts

Macrophages

monocytes circulate in the blood, but when they enter tissue they mature into _________

True

T/F: monocytes arrive to inflammation sites after PMNs

T Cells

monocytes and macrophages present antigens to _________ for the cellular immune response

Histocytes

macrophages in the connective tissue

Osteoclasts

macrophages in the bone

Kupffer Cells

macrophages in the liver

Microglial Cells

macrophages in the neural tissues/brain

Dendritic Cells

macrophages found in most soft tissue but especially in the lymph nodes and spleen; acts as a bridge between the innate and adaptive immune system by acting as messengers (APCs to initiate T Cell response)

Immediate Hypersensitivity

basic function of eosinophils, basophils, and mast cells

Monocytes, Macrophages, and Dendritic Cells

function as phagocytes and to present antigen to lymphocytes, connecting the innate and adaptive immune responses

20-45%

percentage of circulating white blood cells that are lymphocytes

T, B, and NK Cells

three types of lymphocytes

Apoptosis

immature B cells undergo ______ upon recognition of self antigens

Plasma or B Memory

B cells that react with T cells develop into antibody secreting _______ cells or _______ that live for years

DNA Rearrangement

B cell development of specific antigen receptors in the bone marrow is due to ____________

IgM

the first antibody produced on B cells

Isotype Switching

B cells can undergo ___________ upon interaction with T cells, allowing them to change the effector function of the antibody

Thymocytes

immature T cells in the thymus

Independent

T cells and B cells developing their antigen specific receptors in the thymus and bone marrow respectively do so ______ (dependent/independent) of antigenic stimulation

True

T/F: T cells are involved in both cell-mediated immunity and humoral immunity

Self

a T cell will not be selected for maturation if it reacts with _____

Clusters of Differentiation (CDs)

surface molecules on leukocytes with specific functions

CD3 and CD4

a mature T helper cell would have positive CD designation for at least which two CDs?

T Helper Cell (Th)

contacts the displayed antigen fragment and releases cytokines that activate B cells

Cytotoxic T Lymphocyte (CTL)

cytotoxic to host cells infected with intracellular pathogens

MHC Class I

present in all nucleated cells and displays endogenous antigens to cytotoxic T-cells

False

T/F: most NK cells are T cells

CD16 and CD56

NK cells express which two CDs?

NKT Cells

cells that function like both NK cells and T cells, with limited receptor diversity

Thymus

reached maturity prior to puberty and then slowly loses function

Bone Marrow

acts as a secondary lymphoid organ because of recirculation

Primary Lymphoid Organs

liver and bone marrow

Secondary Lymphoid Organs

lymph nodes, spleen, and MALTS (mucosa associated lymphoid tissues)

Epithelial Cells and APCs

the thymus is involved in the selection process for T cell development and uses its extensive network of __________ and _________ to create its large T cell receptor repertoire

Spleen

major filtration organ and acts as a large lymph node in the circulation

2 Liters

how many liters of lymph are returned to the blood every day?

Afferent and Efferent

naive B and T cells enter the lymph node through the _____ lymphatic vessels, percolate through the nodes, and exit through the ______ lymphatic vessels