chapter 17 ___________defenses of the host: the immune response ______________ antibody and...
TRANSCRIPT
Chapter 17
___________DEFENSES of the HOST:
THE IMMUNE RESPONSE
______________ ANTIBODY and LYMPHOCYTE
RESPONSE to an ANTIGEN
____________________
• Study of the defense mechanisms against infectious agents and foreign substances– Surveillance of the body– Recognition of foreign material– Destruction of foreign material
• Includes nonspecific and specific immunity– Nonspecific or _______: includes 1st and 2nd line of
defense
– Specific or ________: includes 3rd line of defense
• White blood cells (WBC) or leukocytes are play an important role
____________ IMMUNITIES - SPECIFIC
SUMMARY OF THE DIFFERENT ____________ IMMUNITIES
________ IMMUNE RESPONSEAdaptive Immunity
Third line of DefenseSpecific immunity is a complex interaction of
immune cells reacting against antigens• _________ RESPONSE
– First response to Ag– May take a week or more to develop
• __________ RESPONSE– Immune system remembers pathogen on subsequent
exposure– Immediate response
DIVIDED INTO 2 CATEGORIESHUMORAL IMMUNITY
-Eliminates _________cellular pathogensCELLULAR IMMUNITY
-Eliminates _______cellular pathogens
HUMORAL IMMUNITYproduction of specific _____________ against
foreign substances called antigens
PROPERTIES of __________• Substances that trigger _____ production or other
immune response: Antibody generator• Types : Proteins, polysaccharides- induce strong
immune response :Lipids, nucleic acids- weak response • Recognition of antigen directed at antigenic determinant or _______________-specific area on Ag against which Abs are formed
OVERVIEW of ________ IMMUNITY
• Mediated by B lymphocytes– a.k.a B cells
• Develops in bone marrow
• B cell receptors bind to Ag: triggers proliferation of B cells into– _________ cells
• produce antibodies
• antibodies produced when antigen binds to B cell receptor
– _________ cells
Extracellular Antigen
Proliferation & Differentiation of Activated B Cell
Plasma cell
Activates B cells that bind
Ag
Antibody Production
Ab + Ag
Memory cell
Helper T Cell
B Cell
Cellular Immunity
PROPERTIES OF _____________products of B Cell Activation
PROPERTIES of B CELLS:• Special group of
lymphocytes• Produced in bone marrow• Mature B cells migrate to
lymphoid organs• Produce: plasma cells
-produce Abs
memory cells
CLASSES of ANTIBODIES:1. IgG2. IgM3. IgA4. IgD5. IgE
• 80% of serum antibodies
• Also present in lymph, intestine, and tissue fluids
• Cross placenta– Protects fetus and newborn
• Fix complement
• Enhance phagocytosis
• Neutralize toxins & viruses
PROPERTIES of __ ANTIBODIES
PROPERTIES of
IgM ANTIBODIES• First Ab produced in
response to infection• Agglutinates microbes• 5-10% of serum
antibodies
PROPERTIES of IgA ANTIBODIES• Protection for
newborns• Mucosal protection• Present In secretions• 10-15% of serum Abs
PROPERTIES of IgD ANTIBODIES
• In lymph and on B cells• May act to delete defective B cells• Help initiate immune response• 0.2% of serum Abs
PROPERTIES of IgE ANTIBODIES
•On mast cells and basophils•Allergic reactions•Lysis of parasitic worms•0.002% of serum Abs
CLONAL SELECTIONthe proliferation of antigen-activated __ cells
(form secondary response to
antigen)(involved in antibody production)
CONSEQUENCES of ANTIBODY-ANTIGEN INTERACTIONS
1. ______________– Blocks adhesion of bacteria
and viruses to mucosa– Prevents toxin from interacting with
cell
2. Immobilization and prevention of adherence– Antibody bonding to cellular _______
to interfere with function
3. Agglutination and precipitation– Clumping of bacterial cells by
specific antibody• Bacteria more easily phagocytized
4. Opsonization– Coating of bacteria with antibody
to enhance _______________
5. ___________ (serum proteins involved with innate, non-specific immunity) – Antibody bonding triggers
classical pathway
6. Antibody-dependent cellular cytotoxicity– Multiple antibodies bind to a cell
which becomes target for certain nonspecific immune cells
CONSEQUENCES of ANTIBODY-ANTIGEN INTERACTIONS cont’d
RECOGNITION of SELF and NONSELF _____________
– Glycoprotein receptors located
on the surface of _______ cells– Role: recognition
• Confer specificity and _________ • Recognized by lymphocyte
cells as “self”• Lymphocytes recognize microbe
receptors as “nonself”– EX.: Major Histocompatability Complex
CLONAL ________________– The process of destroying B and T cells that react
to self as foreign Ags
CELL MEDIATED IMMUNITY• SPECIFIC CELLS
– T ________________• Respond to _____cellular antigens• Produce and respond to cytokines (chemical
messengers)• Subset of T cells with unique CD receptors
– Helper T cell/CD4– Cytotoxic T cell/CD8
• NONSPECIFIC CELLS– ANTIGEN PRESENTING CELLS
• ______________• ______________ cells
– NATURAL KILLER CELLS
SOME TYPES of T LYMPHOCYTES1. ________ T CELLS
– Regulate immune response to antigens by releasing cytokines (chemical messengers)
– Cytokines activate: • Other T cells, delayed type hypersensitivity)
• B cell production and differentiation• Macrophages
2. __________T CELLS– Bind and lyse cells (apoptosis)
• microbes, viral infected cells, foreign cells, cancer cells
– Mode of action • ___________ production• make lesions in the membrane of infected cells
• ___________– degrade proteins– Induce target cells to undergo apoptosis
ROLE of ____ T LYMPHOCYTES IN ANTIGEN RECOGNITION AND RESPONSE
• T lymphocytes have multiple copies of T cell receptors– Receptors have variable
sites for antigen bonding
• T cell receptors interact directly with “presented” antigen– T cell receptor does not
react with free antigen– Antigen must be
presented by an antigen presenting cell:
• B cells• Macrophages• Dendritic cells
ACTIVATION OF __________ T LYMPHOCYTES CELLS BY T
DEPENDENT AGS(CELL-MEDIATED CYTOTOXICITY)
NONSPECIFIC CELL MEDIATED IMMUNITY
• Activated ____________:
Macrophages stimulated by ingesting Ag or by cytokines• ________ Cells
Present antigens• Natural Killer Cells: Lymphocytes that destroy microbes, virus-infected cells, tumors
CELL COMMUNICATION IN IMMUNITY• Markers: the “eyes” and “ears” of the cell
– Cell surface ___________
• ________: the “voice” of the cell-chemical communicators– Small proteins released from human cells that
encounter foreign matter Two major classes of cytokines:
• _________ – important in control of viral infections• _________ – produced by leukocytes, important in innate
and adaptive immunity
• ___________ Molecules: the “hands” of the cell– Allow cells to adhere to each other– Recruit phagocytic cells to site of injury
SUMMARY OF MAJOR COMPONENTS OF ______________________