Test 2
Immunity, HIV/AIDS
Antigen and Antibodies
- Antigens are presented on cells as a “name tag”
- Antibodies are made in response to any antigen or “name tag” that don’t belong
- Antibodies are light or heavy chains that are Y-shaped with specific antigen shaped
receptors on the top of the Y
- Antibodies bind to antigens and perform several actions
Immune Response of Self vs. Non-Self (B’s and T’s Responses)
- Self is Determine from Non-Self through monitoring Antigens
- B-Cell Response to Antigen
oUnsensitized B-Cells Presented an Antigen (Soluble antigens)
oB-Cell antigen receptor binds to the antigen
oBecome sensitized to that specific antigen
oPresent antigen through MHC Class II Antigen Complexes to Helper T’s
oHelper T’s help B Cells Differentiate
oDifferentiate into Plasma B’s and Memory B’s
oPlasma B’s Make Antibodies for that antigen
Plasma B’s already in circulation are stimulated by memory B’s
Also stimulated by the soluble antigen floating around
oMemory B’s remain in circulation to stimulate Plasma B’s to make Antibodies if
memory B’s are exposed again to the same antigen
- T-Cell Response to Antigen
oUnsensitized T-Cells are Presented an Antigen on an infected cell
oT-Cells become sensitized to that antigen
Realize that antigen means infected
oT-Cells Clone themselves, and differentiate into 4 Types
Helper, Suppressor, Memory, Cytotoxic
oHelper T’s
Search for B-Cells presenting the same antigen it’s sensitized to
Helper T’s give Non-Differentiate B-Cells cytokines
Differentiates them into the Plasma cells and Memory B cells
Plasma B Cells start making antibodies to the antigen
oSuppressor T’s
Protect Healthy Cells
oMemory T’s
Remain in Blood Stream and Guard against reinfection of the same
antigen
Stimulate Helper T’s to go activate B Cells presenting same antigen
oCytotoxic T’s
Are sent out in search of that specific antigen being presented by any
MHC Class I Antigen Complex
Are activated by recognition of that antigen on MHC Class I Antigen
Complex
Release Cytolytic Enzymes, Toxic Cytokines, and Pore Forming
Molecules
Types of Immunity
- Natural/Innate (Non-Specific)
oSpecies and Host Dependent
oPresent at Birth
oVery General Immunity d/t broad receptors
Broad receptors allow for bonding to many antigens
- Active Acquired
oWhen Host is exposed to the antigen through immunizations or natural exposure
System has to work to protect you and develop the cells to protect you
- Passive Acquired
oWhen Pre-Formed Antibodies and/or T-Lymphocytes are Transferred to Recipient
Immunoglobulins, Anti-Venom, Through Placenta and Breast Milk
Components of the Immune System
- Bone Marrow, Thymus
- WBC’s, Mast Cells, Dendritic Cells
- B/T Cells
- Antigens and Antibodies
Role of Macrophages, Lymphocytes, Cytokines
- Macrophages
oFirst Phagocyte invading organisms come in contact with
oPresent antigens of engulfed cells that need to be destroyed on MHC Class II
Antigen Complexes
- Lymphocytes
oAdaptive/Acquired Immunity
oB Cells an T Cells
oSelf vs. Non-Self Differentiation through Antigen Monitoring
- Cytokines
oPro or Anti Inflammatory Proteins
oSecreted by Cells of the Innate and Acquired Immune System
oWork by binding to receptors on target cells and activate intracellular responses
oHelper T Cells secrete to activate
Differentiate B-Cells
Activate Cytotoxic T’s
Immunoglobulins
- Produced by Plasma B-Cells
oHelper T Cells Stimulate Differentiation and Production
oMemory B Cells Stimulate Production
oStimulated by Plasma B Receptors
- Types: IgA, IgD, IgE, IgG, IgM
oIgA
Secretions of Body
Mucosa’s of the Body (Tears, Saliva)
Protect Passageways in the body
oIgD
Lining of Chest and Abdominal Cavity
Maturation of B Cells
oIgE
Lungs, Skin, Mucous Membranes
Causes Release of Histamine from Basophils and Mast Cells
oIgG
All Body Fluids
Can Transfer through placenta and breast milk
Activates Compliment and Binds to Macrophages
oIgM
Blood and Lymph
First antibodies to respond to antigen exposure
oNatural or Immunization
- Respond when they come in contact with the antigen their receptors are specific for
oBind to the antigens to create antigen antibody complexes
oAfter Binding, several more actions occur
Agglutination: Clump all the antigens together
Release antitoxins to neutralize the toxins released by cells that don’t
belong (Bacteria)
Lysis of the membrane surrounding the cell that doesn’t belong, killing the
membrane
Opsonization to coat the pathogen in proteins (antibodies and compliment)
to identify them as foreign cells that need to be phagocytized
Allergic Response Mediators
- Primary Mediator is Histamine
- Histamine is released by basophils and mast cells
- When allergen is exposed to cells, it stimulates differentiation of B-Cells
- Plasma B’s Secrete IgE antibodies which cause secretion of histamine by basophils and
mast cells
Hypersensitivity
- Type I
- Type II
- Type III
- Type IV
Stages of Illness
- Incubation, Prodromal, Acute, Convalescent, Resolution
oIncubation Period: Susceptible host is found, begins to grow and multiply
Feel fine, not aware of anything wrong
Can infect others
oProdromal Period: Vague time between incubation period and acute phase
Begin to have a nagging headache, low-grade fever, feeling you’re getting
sick
Can infect others
oAcute Phase: Time during which you feel all of the symptoms that come with
what you are infected with
oConvalescent: No longer infected
Begin to feel better, but still feel bad because body is recovering
oResolution: ALL BETTER
Chain of infection
Nosocomial infection
Types and role of WBCs in infection
Major histocompatibility complex (MHC I and MHC II)
HIV/AIDS—etiology, manifestations, treatment, prevention
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