Micro J210 Adaptive Immunity

-The body's abilitiy to recognize and defend itself against distince invaders and their products

• -Specificity
• -Inducibility
• -Colonality
• -Unresponsiveness to self (tolerance)
• -Memory

• -Humoral immue responses
• -Cell-mediated immune responses

• -B lympocytes (B cells)
• -T lymphocytes (t Cells)

• There is a T Helper cell that will either
• 1. Tell B cells to release antibodies
• 2 Use cytokines to get T cytotoxic cells to work

• -Lymphatic vessels, cells, tissues, and organs that screen the tissues of the body for foreign antigens.
• -The flow of lymph, one-way system that conducts lymph from tissues and returns it to the circulatory system

• -Liquid with similar comnposition to blood plasma
• -Arises from fluid leaked from blood vessels into surrounding tissues

• -Red bone marrow
• -Thymus
• Where cells undergo maturation

• -Where matured cells reside and function
• -Lymph nodes
• -Spleen
• -Tonsils
• -Mucosa-Associated lymphatic tissue (MALT)

• -Small, bean- shaped structures in the body that are part of the lymph system.
• -Found singly or in groups, may be small or large.
• -Can be felt in neck, groin, and underarms
• -When a part of the body is infected, nearby lymph nodes can be swollen

• -Molecules that the body recognizes as foreign and worthy of attack
• -Recognized by 3D regions called epitopes (8 amino acid long)
• -Include bacterial components, proteins of virus, fungi, and protozoa
• -Food and dust have antigenic particles
• -Antigens provoke a specific immune response

• -Antigens that have entered the body from the outside, by inhalation, ingestion, or injection
• -These are broken up or presented to T cells

• -Antigens that have been generatedc within previously normal cells as a result of normal cell metabolism or because of viral or intracellular bacterial infection.
• -Virus has non cell antigen

Usuallly a normal protein or complex of proteins

-When cells of blood orginate from one common stem cell

• -Arise and mature in red bone marrow
• -Found in spleen, lymph nodes, and MALT
• -Small % circulate in blood
• -Major function is secretion of antibodies

• -B-cell receptor, has specificity.
• -Each B cell generates a single BCR
• -Two variable regions of teh BCR form the antigen-binding sites
• -The entire repertoire of an individuals BCRs is capable of recognizing millions of different epitopes.
• -Grabs the antigen
• -Has a constant area and variable is where antigen is attached, and is attached to the cell

-The antigen stimulates a B cell and it releases immunoglobulins.

-Y shape, with a variable area for antigens to attach and then a costant middle.

• -Specificity
• -Antibodes are immunoglobulins similar to BCRS
• -Secreted by activated B cells called plasma cells
• -Have identifcal antigen-binding sites and antigen specificty as the BCR does

• -Antigen-binding sites are complementary to epitopes (lock and key)
• 6 functions:
• 1. Activation of complement and inflammation
• 2. Neutralization
• 3. Opsonization- the sauce, better for PMN to get
• 4. Agglutination- clumping
• 5. Killing by oxidation
• 6. Antibody-dependent cellular cytotoxicity (ADCC) NK cells kill easier with coating

By neutralization so it cant bind to cells

• -threats confronting the immune system are variable
• -Class involved in immune response depends on the type of antigen, portal of entry, and antibody function needed.

-IgM, IgG, IgE, IgA, IgD

• First antibody produced
• Largest
• Pentameric (five)

• -Most common and longest-lasting antibody
• -in serum
• -Can cross the placenta because its the smallest

• Associate with body secretions
• Dimeric
• Protective secretions

Involved in reponse to parasitic infections and allergies

-Exact function not known

• Produced in bone marrow, but matures in Thymus
• Only about 4/100 are mature
• -Circulate in the lymph and blood and migrate to lymph nodes, spleen, and peyer's patches
• -Antigen-binding sites are complementary to epitopes
• -Have T cell receptors (TCR) on their cytoplasmic membrane.

-one that has not incountered any antigen

• T cell receptor
• -Does not bind directly to the antigen
• -Specificity
• -Does not recognize epitopes directly
• Oly bind epitops associated with a MCH protein
• -Act against cells that harbor intracellular pathogens
• -Cannot get secreted
• -Shape is like two poles with variable then a constant regions, made of carbs, and a disulfide bond

Antigen presenting cell

The APc stimulates T cells to become helper cell, which stimulates B cells and uses cytokines to get help from T cytotoxic cell

- Based on surface glycoproteins and characteristic functions

- Cytotoxic, Helper, and regulatory

• -Directly kills other cells (virally infected cells)
• -CD8+

Helps regulate the activates of B cells and cytotoxic t cells

Represses adaptive immune responses

Induction of a certain antigen which causes proliferation and leads to effector memory

• -It is vital that immune response not be directed against autoantigen
• -Body elimiantes self-reactive lymphocytes
• -The immature B cells whose BCR bind too strongly to self antigens, will not mature
• -If B cells are found to be highly reactive to self they are idcued to undergo apoptosis

During maturation in the thymus, T cells that react to autoantigens are eliminated by being induced to undergo apoptosis

• -Cells of immune system communicate by releasing soluble regulatory proteins that act on other cells
• -Secreted by various leukocytes
• -The complex web of signals among all the cells of teh immune system is called cytokine network

• Cytokine of the immune system
• -Signal among leukocytes

• Cytokine of the immune system
• -Antiviral proteins that may act as cytokines

• Cytokine of the immune system
• -Proteins that stimulate stem cells to divide

• Cytokine of the immune system
• -Secreted by macrophages and T cells to kill tumor cells and regulate immune responses and inflammation

• Cytokine of the immune system
• Chemotactic cytokines that singal leukocytes to move

Yes and yes

• -MHC
• -Group of antigens 1st identified in graft patients
• -Important for determining compatiability of tissues for tissue grafting
• -Major histocompatibility antigens are glycoproteins found in the membranes of most cells of vertebrate animals
• -Hold and postion antigenic determinants for presentation to T cells
• Antigens bind in the groove of MHC molecules

- Present on the surface of all nucleated cells in the body

-Present on the surface of all professional antigen presenting cells aka macrophages

-Dendritic cells, macrophages and B cells

• -Antigen that enters the skin is loaded on dendritic cells, which migrate to draing lymph nodes. In the lymph nodes, naive T cells are activated by antien-loaded dendrici cells and start to proliferate and differentiate
• -These antigen-responisve cells acquire expression of specific adhesion molecules and chemokine receptors that enable them to migrate to the effector site.
• -On all CT graft, sees the antigen and presents to T cell

• -Antigens processed for MHC proteins to dispaly epitopes
• -Different processes for endogenous and exogenous antigens
• Endogenous- MHC I
• Exogenous- MHC II

• -Reespond to intracellular pathogens and abnormal body cells
• -Most common is intracellular pathogens are viruses
• -The response is also effective against cancer cells, intracellualr protozoa, and intracellular bacteria.
• -The cell is infected, expresses virus antigen, T cell comes and kills that cell

• -Cytotoxic T cells
• -Antigen presentation by APC MHC II
• -Helper T cell differentiation
• -Clonal expansion- IL-2R
• -Self-stimulation
• MHC I

-Kills virally infected cells. T cell recognizes by epitopes, after MHC I, then caues infected cell to apoptosis and macrophages clean up the mess

• -Some activated T cells become memory T cells
• -Persist for months or years in lympoid tissue
• -immediately functional upon subsequent contacts with epitope specific to its TCR
• -Ex. vaccinations

• -Against exogenous pathogens
• -Is activation of B cells which release Immunoglobulins
• -T dependent and T indenpendent of B cells

• -B and T cells that have not yet recognized an antigen via their BCR/TCR are called naive lymphocyes
• -Most protein antigens that activate naive B cells are called T dependent antigens. The B must first interact with effector T4 lymphocytes before they have a response

• -It relaese cytokines that actiate B cells to proliferate into antibody-secreting B cells and plasma cells
• -Some B cells differentiate into B memory cells for heightened 2nd response against antigen

• -Majority of cells produced during B cell proliferation
• -Only secrete antibody molecules complementary to the specific antigen
• -Short lived cells that die within a few days of activation-their antidies and progeny can persist

• - T depedent
• -Immunological memory
• -Produced by B cell proliferation but no not secrete antibodies
• -Have BCRS complementrary to teh antigenic determinatnt that triggered production
• -Long lived cells that persist in lymph tissue
• -Initiates antibody production if antigen is encountered again
• -Form at first exposure

• -t independent antigens are antigens which can directly stimulate B cells to produce antibody without T cell hep in general.
• -Polysaccharides are T-independent antigens
• -These antigens are characterized by the same antigenic determinant repeated many times (has same epitope)
• -Faster response
• -This is lacking in children, so do not give them polysacchoride vaccine

- IgM then after 5 days IgG goes up then back down after 15 days

-IgM and IgG both high on day 3, IgM goes downn day 6, but IgG stays high because of memory B cells

-Specific immunity acquired during an individuals life

• -Naturally: response against antigens encountered in daily life
• -Artifically: response to antigens introduced via vaccine
• Can be active or passive (antibodies from antoehr indiviudal animal or human)