a&p ch 20 lymphatic system: immunity (adaptive/specific immunity)

How are B cells activated?

Sensitized B cell must bind to an active helper T cell that responds to the same antigen

What is another name for adaptive immunity?

Specific Immunity

What 2 cells coordinate adaptive immunity?

T and B cells

How are B cells activated? What results from this?

activated by T cells expressing MHC class II expressing proteins (CD4 marked cells) activated T cell divides & differentiates into: - helper t cells (secrete cytokines when activated) - memory t cells (inactive)

What are B cells/B lymphocytes?

antibody producing cells

Which type of immunity develops when a child is given a polio vaccine?

artificially acquired active immunity

How do abnormal antigens attached to class I MHC proteins initiate an immune response?

attachment = on surface of the cell's plasma membrane recognition by CD8 T cells initiates immune response

Explain the function of cytokines secreted by helper T cells.

cell-mediated & antibody-mediated immunity

What types of immunity are stimulated by antigen presentation?

cell-mediated immunity antibody-mediate immunity

What do helper t cells secrete? What function does the secretion serve?

cytokines (promote B cell activation)

Identify the 3 major types of T cells activated by class I MHC proteins.

cytotoxic T cells memory Tc cells regulatory T cells

What does it mean to say adaptive immunity has tolerance?

immune response ignores itself

How is natural passive immunity acquired?

maternal antibodies to fetus through placenta or breast milk

What is passive immunity subdivided into?

natural passive artificial passive

Describe antigen presentation.

occurs when an antigen-glycoprotein/antigen-MHC protein forms combo = capable of activating T cells in a plasma membrane. T cells sensitive to this antigen = activated if they contact the antigen on the plasma membrane of the antigen-presenting cell. activates immune response

What are the properties of adaptive immunity?

specificity versatility memory tolerance

What are regulatory t cells? What is another name for this?

t lymphocytes that slow down activities of B & T cells once infection is controlled suppressor t cells

How does artificially acquired active immunity develop?

vaccine administration of an antigen to prevent disease

Describe the process of antibody mediated immunity.

- B lymphocytes & plasma cells recognize antigens - Produce antibodies - Antibodies bind to specific antigen - foreign cells agglutinate & precipitate in circulatory system or tissues - Phagocytic WBCs (i.e. neutrophils & macrophages) eat antigens (eliminating them)

How do cytotoxic t cells destroy cells?

- Perforin (destroys cell mem) - Cytokines (chem signals for apoptosis) - Lymphotoxins (disrupt cell metabolism)

What is adaptive/specific immunity subdivided into?

Active (Adaptive) Immunity Passive (Adaptive) Immunity

Describe antigens that would undergo antibody mediated immunity.

Antigens can be from flagella or cell mems of protozoans, protein coat of a virus or the surface of a fungal spore

What needs to occur before a B cell can be activated by a helper T cell? Explain.

B cell must be sensitized · B cell must encounter its specific antigen via its antibodies · antigen is endocytosed & presented back to the surface as part of the class II MHC complex

Describe CD markers.

CD markers refer to a class of membrane proteins. CD = "cluster of differentiation." T cell plasma mems contain CD proteins. T cells w CD8 markers respond to antigens presented by class I MHC proteins. T cells w CD4 markers respond to antigens presented by class II MHC proteins.

What do antigens in antibody mediated immunity cause?

Cause the immune system to produce antibodies or immunoglobulins

Where are Class I MHC proteins and Class II MHC proteins found?

Class I MHC proteins: - in plasma membrane of all nucleated body cells Class II MHC proteins: - only in plasma membrane of antigen-presenting cells (APCs) & lymphocytes

What does it mean to say adaptive immunity has memory?

Memory cells allow for a quicker, stronger, & longer response following exposure to the same pathogen at a later date

What do activated B cells divide & differentiate into?

Plasma Cells Memory B cells (inactive)

Define sensitization.

Process by which a B-cell prepares to undergo activation after encountering a specific antigen. Specific antigens bound to mem antibodies are brought into the cell by endocytosis, where the antigens then become bound to class II MHC proteins. Together they then appear on the cell surface.

What does adaptive immunity do? What does it provide?

Protect against specific threats (defenses affect specific pathogen & not other pathogens) Uses lymphocytes Provides specific resistance

How are T cells activated in cell mediated immunity?

T cells activated by major histocompatibility complex (MHC) Class I proteins of CD8 marked

Describe the process of cell mediated immunity.

T lymphocytes = activated by binding antigen, but they cannot bind free antigens Antigens must 1st be engulfed by macrophages antigens = processed internally & displayed macrophage surface T lymphocyte then binds to the antigen which activates T cell & initiates the clonal response (increases # of cells that can recognize the antigen)

What are cytotoxic T cells? What is another name for these cells

T lymphocytes that kill virus-invaded body cells, cancer cells & reject body grafts AKA Killer T cells

What are memory T cells?

T lymphocytes that remain inactive until exposure to the pathogen a second time

What does a vaccine contain? Name some available vaccines.

dead pathogens or live but very weak pathogens - measles - smallpox - polio - tetanus - chickenpox - pneumonia - diphtheria - flu

What is passive immunity?

doesn't require exposure to an antigen to express the antibody (antibody transfer)

How does naturally acquired active immunity develop?

exposure to infection/antigens in the environment

How is artificial passive immunity acquired?

gamma globulin immune serum (after hepatitis exposure & snake bite (anti-venom)) dog bite (rabies serum)

What is the result of T cell activation in cell-mediated immunity?

generates 3 populations of T cells - cytotoxic t cells (killer t cells) - memory t cells - regulatory t cells (suppressor t cells)

What does it mean to say adaptive immunity has specificity?

has a specific antibody response to a specific antigen

What does it mean to say adaptive immunity has versatility?

has lots of lymphocytes, which recognize different antigens/pathogens can divide & produce clones to respond to a specific antigen

If you observed a higher than normal number of

higher

What is the major histocompatibility complex (MHC)?

portion of chromosome 6 containing genes that control the synthesis of membrane glycoproteins

What are plasma cells & what do they do?

replicated B cells that enter tissues & produce large #s of the same antibody requires cytokine stimulation from active helper T cells

What is the function of inactive memory B cells?

respond to future exposure by differentiating into plasma cells

Describe the immune response for natural versus artificial exposure.

same immune response don't experience full extent of the symptoms from the disease

What is active immunity? What is it subdivided into?

when B cells contact antigens & produce antibodies natural active immunity artificial active immunity