Intro to Immune System Flashcards
What are the primary lymphoid organs and what cells do they produce?
Bone marrow – All cells except T-cells
Thymus – T-cells
What are the secondary lymphoid organs?
Spleen
Lymph nodes
Mucosal immune tissues
What comprises the absolute white blood cell count?
Neutrophils Basophils Eosinophils Monocytes Lymphocytes
Which leukocytes are mononuclear?
Monocyte
T-cell
B-cell
NK cell
These hematologic laboratory tests provide the complete hematologic picture of the case, and can often provide a diagnosis or diagnostic clues when interpreted by a physician.
CBC (complete blood count)
DIFF (differential leukocyte count)
What stain is used to observe and recognize leukocytes on a smear of peripheral blood?
Giemsa stain
In a WBC (white blood count), what cells are present the least in the blood and which are the most?
Basophils
Neutrophils
Blood smear technique doesn’t allow differential count of B cells, T cells, and NK cells because these cells appear the same under a microscope. For this, a special technique called _______ _______ was developed using Abs recognizing specific Ags. These are selectively expressed one each type of leukocyte.
Cluster of differentiation (CD)
CD molecules are cell surface markers useful for identification and characterization of leukocytes when cells can’t be differentiated based on microscopic morphology. CD Ags that are well characterized are assigned an arbitrary number (i.e., CD1, CD2). What are the CD Ag markers for the leukocytes?
T-Cell = CD3; CD4; CD8
B-Cell = CD19; CD20
NK Cell = CD56
Macrophage/Monocyte = CD14
Direct (high level) and indirect (low level) ________ _______ with anti-CD Abs is used for identification of leukocytes in the specimen.
Fluorescent microscopy
What are the phagocytes?
Neutrophils
Macrophages
***Could also be granulocytes and DCs
The primary function of phagocytes is to ingest and destroy microbes and get rid of damaged tissues via their _______ function.
Scavenger
How do phagocytes destroy microbes?
By ingesting them via phagocytosis
Activated phagocytes also secrete ________ which promote and regulate immune responses.
Cytokines
If you have a lot of pus in a cut, what is largely present?
Neutrophils
Neutrophils mediate the earliest phases of _________ reactions.
Inflammatory
***Neutrophils produce inflammatory mediators – cytokines, prostaglandins, and leukotrienes
What is present in the granules of neutrophils?
Peroxidase
Lysozyme
Degradative enzymes
Defensins
T/F. Neutrophils are long-lasting and can function for months.
False. Neutrophils live for hours or a few days then die by apoptosis.
This is the term for an elevated WBC greater than 11,000 cells/mcL in non pregnant adults. It is a common sign of infection, particularly by extracellular bacteria.
Leukocytosis
This is the most common type of leukocytosis because these cells are the most abundant granulocyte in blood circulation.
Neutrophilia
The normal reaction of bone marrow to infection or inflammation leads to an increase in the number of WBCs, predominantly neutrophils and less mature cell forms. Termed the _________.
Left-Shift
***Means >5 percent immature neutrophils. The bone marrow is producing more WBCs and releasing them into blood before they are fully mature.
This is the term for the reduction in the circulating WBC count to less than 4000/mcL.
Leukopenia
Leukopenia is usually characterized by _________, a reduced number of circulating neutrophils. Often caused by cancer chemotherapy or radiation therapy.
Neutropenia
***Suspect in people who have frequent or unusual infections.
What are the ways a neutrophil can eliminate a pathogen intracellularly and extracellularly?
– Via phagocytosis and degradation by ROS or antibacterial proteins
– Antibacterial proteins are released from neutrophil into the ECM and kill
– Release of NETs (neutrophil extracellular traps) to ECM which immobilize pathogens and facilitate phagocytosis
What are NETs composed of?
Core DNA element that attaches histones, proteins, and enzymes released from granules
________ are the main “mononuclear” phagocytes in the blood, where as ________ reside in the tissues.
Monocytes
Macrophages
________ lifespan can switch dramatically, from prolonged survival during inflammation to apoptosis as inflammation resolves.
Monocytes
This is the term for an increased number of monocytes in the blood, and can occur in response to chronic infections, autoimmune disorders, certain cancers, and sarcoidosis (a proliferation of resident macrophages in tissues).
Monocytosis
This is the term for a low number of monocytes in the blood. Can occur in people receiving chemotherapy.
Monocytopenia
Tissue _______ _______ are a heterogenous population of immune cells that fulfill tissue-specific functions. They are long-lived cells derived from hematopoietic progenitors in the yolk sac.
Resident macrophages
***They are “residents” of specific tissues
Monocytes migrate into tissues where they differentiate into ________ _______, especially during inflammation. They are involved in inflammatory reactions and tissue remodeling that repairs “collateral damage” produced by hypersensitivity reactions.
Inflammatory macrophages (monocyte-derived)
These cells protect against helminthes (parasites) and are responsible for allergic reactions. They all have cytoplasmic granules filled with inflammatory and antimicrobial mediators.
Mast cells
Basophils
Eosinophils
Mast cells are in the (BLOOD/TISSUE), while basophils are in the (BLOOD/TISSUE). Both contribute to defenses against parasites and play key roles in allergic and anaphylactic reactions.
Tissue
Blood
Mast cells and basophils contain basophilic (purple-black) granules that contain…
Histamine
Serotonin
Heparin
Cytokines and chemokines
These cells are the body’s “1st line of defense” because they distributed all over the tissues in locations where pathogens and allergens are frequently encountered.
Sentinel cells
***Mast cells; DCs; Tissue macrophages
This is the term for a pathologic increase in mast cells within tissues.
Mastocytosis
People affected by mastocytosis are susceptible to itching, hives, and anaphylactic shock, caused by the release of ________ from the abundant mast cells.
Histamine
Most cases of mastocytosis are localized to skin and called cutaneous mastocytosis. ________ ________ is the most common form of cutaneous mastocytosis.
Urticaria pigmentosa
The most prominent feature of the eosinophils are their large secondary granules containing four _______ _______.
Basic proteins (major basic protein)
What is in the granules of eosinophils?
Histamine
Peroxidase
Lipase
Major basic protein
T/F. Basic proteins of eosinophils are involved in anti-parasitic defense mechanisms as toxins directed against helminths.
True
This is the term for a peripheral blood eosinophil count of >500/mcL.
Eosinophilia
The most common cause of _________ in the US is allergic or atopic disorders (typically respiratory or dermatologic). Other causes are infections (typically parasitic) and certain tumors.
Eosinophilia
These cells recognize and destroy a variety of target cells without any prior stimulation or immunization.
NK cells
NK cells recognize Ags normally expressed on host cells. If one of those Ags is not expressed on host cells, the absence of that Ag activates NK cells. Because of this BROAD specificity for Ags, NK cell functions like a cell of _______ immunity.
Innate
Where do B-cells mature?
Spleen
When a (MATURE/IMMATURE) T-cell is Ag-stimulated, it gives rise to the development of cell-mediated adaptive immunity.
Mature
Cell-mediated immunity mediates host defense against (EXTRACELLULAR/INTRACELLULAR) microbes, such as viruses and some bacteria, where they are inaccessible to circulating Abs. It is the killing of infected host cells that eliminates the reservoirs of infection.
Intracellular
Some T lymphocytes, called _______ _______ also help B cells to make high affinity Abs and thereby contributing to the eradication of extracellular microbes.
T helper cells
In cell-mediated immunity, T helper cells activate _________ to kill phagocytized microbes, or ________ ________ to directly destroy infected cells.
Macrophages
Cytotoxic T lymphocytes (CTLs)
This is the term for the hypothesis that explains the specific nature of the immune response in which the diversity among various cells for the recognition of specific Ags exists prior to their exposure to the Ag. An exposure to a particular Ag causes the proliferation of the appropriate Ag-specific cell.
Clonal selection/expansion
All immunocompetent individuals have many distinct lymphocytes, each of which is specific for a different ______.
Ag
When Ag is introduced into an individual, lymphocytes with receptors for this Ag seek out and bind Ag and are triggered to proliferate and differentiate giving rise to _______ of cells specific for the Ag.
Clones
The cells from the clones or their products specifically react with the Ag to neutralize or eliminate Ag. Some Ag-specific cells late in the immune response is responsible for the ________ involved in adaptive immunity.
Memory
