L2: Cells and Tissues Flashcards Preview

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Flashcards in L2: Cells and Tissues Deck (33)

What are non-self entities?

Things that express molecules (antigens) that can be recognized by cells of the immune system


What are the major groups of human pathogens?

Viruses, bacteria, fungi, parasites


How was smallpox vaccine discovered?

Smallpox is caused by the variola virus. Discovered that milkmaids, who were exposed to cow pox (variolae vaccinae) did not get smallpox. Then took scrapings from pustules of milkmaid and inoculated someone, then did the same w/ small pox and pt did not get smallpox. Smallpox was officially eradicated in 1979


What is the most primitive form of the immune system?

Innate immunity


How long after infection does innate immunity kick in?

Minutes to hours


What does the innate immune system consist of? What does the adaptive immune system consist of?

Innate: epithelial barriers, complement, phagocytes, NK cells

Adaptive: B lymphocytes, T lymphocytes


What microbe does humoral immunity respond to? What are the responding lymphocytes? What is the effector mechanism?

Microbe: extracellular bacteria

Responding lymphocytes: B lymphocyte

Effector mechanism: secreted antibody, causing elimination of bacteria


What microbe does cell-mediated immunity respond to? What are the responding lymphocytes? What is the effector mechanism?

Microbe: phagocytosed microbes in macrophage and virus-infected cell

Responding lymphocytes: T lymphocytes

Effector mechanism: For phagocytosed microbes in macrophage, causes activation of macrophage leading to microbial killing

For virus-infected cell, causes lysis of infected cell


How are humoral and cell-mediated immunity transferred?

Humoral immunity is passively transferred by serum (antibodies)

Cell-mediated immunity transfer requires transfer of cells


What is the effector function of B lymphocytes?

Produces antibodies

Causes neutralization of microbe, phagocytosis, complement activation


What is the effector function of helper T lymphocytes?

Produces cytokines

Causes activation of macrophages, inflammation, and activation (proliferation and differentiation) of T and B lymphocytes


What is the effector function of cytolytic T lymphocytes?

Killing of infected cell


What is the effector function of natural killer (NK) cells?

Killing of infected cell


What are the phases of the adaptive immune response?

Recognition phase
Activation phase
Effector phase: elimination of antigens
Decline (homeostasis): apoptosis
Memory: surviving memory cells


When antigen comes in, why is there a lag time before immune response occurs?

There is activation, clonal expansion, and differentiation of B cells to produce antibody


How is secondary immune response different from primary immune response?

Lag time is shorter
Level of antibody produced is higher
Quality of antibody is more specific
Lasts longer in circulation


In hematopoiesis, what determines what the stem cell becomes?

Microenvironment of bone marrow and also cytokines that are present


Where does B lymphocyte and T lymphocytes maturation occur?

B lymphocytes in bone marrow

T lymphocytes in thymus


Once they are released to the blood, where do B and T lymphocytes take up residence?

In the peripheral lymphoid organs

Lymph nodes
Mucosal and cutaneous lymphoid tissues


What criteria are used to distinguish various lymphocyte subsets?

Cell surface markers
Patterns of cytokine production
Functional characteristics


What are significant surface markers of human B cells?

Antibody molecule that is stuck in the membrane w/ the 2 antigen combining sites exposed



What are the significant surface markers of human T cells?


T helper cell: CD4

T cytotoxic cell: CD8


What are the T cell subsets? What do they do?

Helper T lymphocytes: make cytokines that amplify the immune response; cause activation of macrophages, inflammation, activation (proliferation and differentiation) of T and B lymphocytes

Cytolytic T lymphocytes (CTLs): killing of infected cell


How are natural killer cells different from cytotoxic T cells?

They are part of innate immune response that don't require antigen recognition to kill infected cell


What is an alternate name for NK cells?

Large granular lymphocytes bc of the unique granules in their cytoplasm


What are the significant cell surface markers of human monocytes/macrophages?



What are the antigen presenting cells?

Dendritic cells and macrophages


Describe how antigen presenting cells present antigen peptides

1. Bacterium infects macrophage and enters vesicle, producing peptide fragments
2. Bacterial fragments are bound by MHC class II in vesicles
3. Bound peptides transported by MHC class II to the cell surface


What does T helper cell recognize?

Recognizes complex of bacterial peptide w/ MHC class II and activates macrophage


What lymph vessels go into and out of lymphoid tissues?

Afferent vessels coming in and efferent going out


Where do all lymphatic vessels coalesce?

In the major lymphatic vessel of the body, the thoracic duct, which empties into the peripheral circulation around the great vessels near the heart


Where do B cells reside in lymph nodes?

In germinal centers (follicles) which are in the periphery of the lymph node


Where do T cells reside in the lymph node?

In the T cell zone, which is just beneath the B cell zone