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38 Cards in this Set
- Front
- Back
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What is adaptive immunity? |
the body's ability to recognize and then mount a defense against distinct invaders and their products, whereto they are protozoa, fungi, bacteria, viruses, or toxins |
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Adaptive immunity involves activity of what? |
Lymphocytes - B cells and T cells |
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What are B cells? |
-arise and mature in the red bone marrow of adults -main defensive cells of humoral immunity -secrete antibodies that act against pathogens -aka antibody immunity |
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What are t cells? |
-begin in bone marrow but do not mature here; mature in thymus -regulate adaptive immune responses or attack intracellular pathogens -mount cell mediated immune responses which don't involve antibodies |
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Define cell mediated response? |
immune response used by T cells to fight intracellular pathogens and abnormal body cells |
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What is antibody immune response? |
proteinaceous antigenbinding molecule secreted by plasma cells |
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Why are lymphocytes important? |
play a central role in adaptive immunity |
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What are antigens? |
-molecules that the body recognizes as foreign and worthy of attack -they bind to lymphocytes and trigger adapt. immun. |
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How does the body recognize antigens in regards to their shape? |
epitopes- 3D shapes aka antigenic determinants bc it is the part of the antigen that determines an immune response |
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What are the 3 different types of antigens? |
-endogenous antigens -exogenous antigens -autoantigens |
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Describe autoantigens? |
antigenic molecules derived from normal cellular processes |
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describe endogenous antigens |
-protozoa, fungi, bacteria, and viruses that reproduce inside a body's cells produce endogenous (endo meaning w/in) |
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describe exogenous antigens |
exo meaning without -antigens include toxins and other secretions and components of microbial cell walls, membranes, flagella and pili |
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What are T lymphocytest? |
-T cells - recognized based on surface glycoproteins and characteristic functions
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Describe the specificity of T cell receptors? |
-TCR -only composed of two glycopolypeptide chains -terminal ends have variable regions that grant specific binding properties - antigen binding site -only bind to epitopes -but doesnt recognize epitopes directly |
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Describe the processing of endogenous antigens? 4-5 steps |
-polypeptides are coded by bacteria and catabolized into smaller AA pieces (8-12) -include epitopes of polypeptides -bind onto complementary antigen binding grooves of MHC class 1 molecules in the membrane of ER -This is packaged into a vesicle by a Golgi body and inserted into cytoplasmic membrane -MHC class 1 epitope complex is displayed on cells surface |
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Describe the processing of exogenous antigens |
-antigen-presenting cell (APC) internalizes invading pathogen and enzymatically catabolizes pathogen's molecule -this produces peptide epitopes (phagolysosome) -a vesicle containing MHC class 2 in its membrane fuses with the phagolysosome and each peptide attempts to bind to an antigen binding groove of complementary MCH class 2 molecule -empty MHC molecules are not stable and are degraded off of a cells surface |
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List the 3 types of T lymphocytes we discussed? |
-cytotoxic T lymphocyte -helper T lymphocytes -regulatory t lymphocyte |
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Describe cytotoxic t lymphocyte? |
-directly kills other cells |
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Describe helper T lymphocytes? |
function in assisting in regulating the activity of B cells and cytotoxic T cells during immune responses by providing necessary signals and growth factors |
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Describe regulatory T cells? |
-AKA suppressor T cells -repress adaptive immune responses and prevent autoimmune diseases |
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Describe the clonal deletion of T cells and B cells? |
- is the deactivation of B cells and T cells after they have expressed receptors for self-antigens and before they develop into fully immunocompetent lymphocytes
-B cells deletion occurs in the bone marrow |
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What is the major function of B lymphocytes and antibodies |
- secreting antibodies -secreted by activated B cells called plasma cells -B Cell receptor is a immunoglobulin |
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Describe the specificity of the B cell receptor? |
-BCR - type of immunoglobulin -contains 4 polypeptides chains - two identical longer chains called heavy chains and two shorter (lighter chains) -composed of a symmetrical, epitope-binding, Y-shaped protein in association w/2 transmembrane polypeptides |
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What are 5 functions of antibodies? |
-neutralization of toxins and microbes -opsonization -oxidation by toxic forms of oxygen SA O2, H2O2 and O3 -Agglutination -activation of complement and participation in inflammation |
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Define cytokines |
-soluble regulatory proteins that act as intercellular signals -secreted by various leukocytes
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What are interleukins? |
ILs signal among leukocytes (white blood cells) though cells other than leukocytes may also use interleukins |
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What are interferons? |
-antiviral proteins that may also act as cytokines |
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What are growth factors (when talking about cytokines)? |
-stimulate leukocyte stem cells to divide |
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What is Tumor necrosis factor? |
-TNF -macrophages and T Cells secrete TNF to kill tumor cells and regulate immune responses and inflammation |
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What are chemokines? |
-chemotactic cytokines -signal leukocytes to move to area of infection or move w/in tissues |
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What is cell mediated responses? |
-respond to intracellular pathogens and abnormal body cells |
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What are steps involved in activation of cytotoxic T cells? |
-antigen presentation -helper T cell differentiation -clonal expansion -self-stimulation |
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Describe antigen presentation? |
-dendritic cells (macrophages and B cells) which process antigens and activate cells of immune system |
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What are helper T cells? |
(Th cell, CD4) -in cell mediated immune response a type of cell characterized by CD4 cell-surface glycoprotein; regulates the activity of B cells and cytotoxic T cells |
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Describe colonal expansion? |
-the reproduction of activated white blood cells (lymphocytes) |
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Describe self stimulation? |
Daughter Tc (cytotoxic T) cells activate and produce both IL-2 receptors and more IL-2 therefore becoming self-stimulating |
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Describe antibody immune response? |
-antibody immune responses mounted against exogenous pathogens and toxins -activates only in response to specific pathogens |
