Specific Host Defenses

What is specific immunity

• The third and final line of defense

• Adapts to infections and acquires memory for specific antigens

What is immunocompetence

• The ability of the body to react with foreign substances

What are antigens in regard to specific immunity

• Molecules that stimulate a response by B and T cells

• Proteins or sugar

• Highly individual and specific

• Must not be a normal constituent of the body

What is Epitope

• The portion of an antigen to which an immune cell responds

• Primary signal to the immune system

What are most antigens

• Proteins

• Lipoproteins: cell membranes

• Glycoproteins: blood cell markers

• Nucleoproteins: DNA complexed to proteins

• Polysaccharides (certain bacterial capsules)

• Lipopolysaccharides

What are the stages of Adaptive immune response (3)

• Lymphocyte development and differentiation

• Presentation of antigens

• Challenge of B and T cells by antigen

What is T-lymphocyte response

Cell mediated immunity

What is B-lymphocyte response

Humoral immunityWhat are t

What are three types of cellular communication

• Detection

• Recognition

• Cell communication

What are receptors

• Different markers activate different components of the specific immune response

What is the Major histocompatibility complex (MHC)

• Found on all nucleated cells (aka not red blood cells)

• Critical for recognition of self and rejection of foreign tissue

What are the 3 classes of MHC

• Class 1,2,3

What is Class I of MHC

• Molecules that appear on all nucleated cells, display epitopes of self

What is Class II of MHC

• Appears on macrophages,dendritic cells, and B cells

  • antigen presenting cells: present antigen to T cells

What is class III of MHC

involved with the complement system

What is a superantigens

• Bacterial toxins, potent stimuli for T cells

  • 100x greater activation

    Overwhelming release of cytokines and cell death

    • toxic shock

What are lymphocyte receptors

• Accept or grasp antigens in some form

  • bell cell receptors bind antigens complexed with MHC

  • Receptors have a nearly infinite number of unique antigen interactions

What is the most important cluster of differentiation

• CD3

• CD4

• CD8

• CD10

What are lymphocyte development

• B cells mature in specialized bone marrow

• T cells mature in thymus

What is each mature B and T specific to

A single antigen

How is diversity generated by

• Gene rearrangement

• Every possible recombination occurs

• bad versions thrown out

• Estimated 10 trillion different versions produced by 1 individual

What are Immunoglobulin (ig)

• Large glycoproteins

• Antigen receptors of B cells

• When secreted are antibodies

What is an immunoglobulin structure

• Antigen binding sites

• Variable regions

• Light chains,heavy chains, constant regions

What are isotypes

• Structual and functional classes of immunoglobulins

What is IgA

• Secreted antibodies

What is IgE

• parasites/allergies

What is IgM

• Primary exposure for extracellular pathogens

• Can be coexpressed with IgD

What is IgG

• Secondary exposure of extracellular pathogens

IgA structure and function

• Monomer, circulates

• Dimer,secretions

• Provides specific immunity aganist enteric, respiratory and genitourinary pathogens

• Colostrum

IgM structure and function

• Pentamer (sometimes hexamer

• Too large to diffuse

• very “sticky” to its target

• powerful complient activator

• Activates phagocytes

What is IgG structure and function

• Most common ig in circulation (75%)

• Only antibody to cross the placenta

• Activates phagocytes and complements

• Associated with hypersensitivity

• Detected in diagnostic assays

What is B cell response

• When activated B cells divide and become either memory or plasma cells

• Antibodies attach to their specific antigen mark it for destruction or neutrailzation

What is plasma cells

• Antibody factories

Clonal selection

• The specific B or T cell is activated by an incoming antigen

• 1 lymphocyte pre-programmed for 1 antigen

What is clonal expansion

• Rapid division/production of B or T cell after encounter with its specific antigen

What are helper T Cells

Activate macrophages, assist b-cells and help activate cytotoxic T cells

What is regulatory T-cells

• limit inflammation and autoimmune

What are cytotoxic T cells

• Lead to the killing of infected host cells and foreign cells

What are cell-mediated immunity (CMI)

• Actions of T cells are dictated by APCS

• All t-cells produce cytokines

What is restricted Cell mediated immunity

• require some type of MHC

What is the end result of cell mediated immunity

• mobilization of other immune cells

What is the Helper cells characteristics

• Multiple types all have CD4

• Involved in activating macrophages

  • Directly

  • Indirectly by releasing cytokines

• secretes interleukin

• 65% of t-cell population

What are cytotoxic T cells

• Target and destroy

  • Virally infected cells

  • Cancer cells

  • Cells from other animals and human the most important factor in graft rejction

  • Kill by inducing apoptosis or preforin pathway

What are the steps after a breach when pathogens cross

• Monocytes migrate to the site

• Tissue macrophages ingest the pathogen and initiate an inflammatory response

• Dendritic cells/macrophages ingest the pathogen and present it to T and B cells

What are natural killer cells

• Lack of specificity for antigens

• Detect a lack of MHC

What happens when B and T cells proliferate and differentiate

• Clonal expansion

• Memory cells and plasma cells

• Stimulate and amplify innate responses

• Remember the antigen for rapid response in future

What is Natural immunity

• Acquired through the normal biological experiences of an indvidual

What is artificial immunity

• Acquired through mediccal procedures such as vaccines and immune systems

What is active immunity

• Antigen activates B and T cells to produce immune substances

• Creates money

• Requires several days

• Last for a relatively long time

• Can be natural or artifical in origin

What is passive immunity

• Receiving antibodies from another human or animal

• Instantaneous protection

• Protection is short lived

• Lack of memory for the original antigen

• Lack of antibody manufacturing

• Can be natural or artificial in origin

What did Edward Jenner do

• Cowpox and smallpox

• “vaccination”

What did louis pasteur do

• Anthrax in cows, vet vaccines

What are the basic principles behind vaccinations

• Stimulate a primary response and a memory response

• Prime the immune system for a future exposure

• If a pathogen enters, the response will be immediate, powerful and sustained

What is vaccine adjuvants

• Special binding substance used for some vaccines

  • enhances immunogenicity

  • Prolongs retention at the injection site

  • Facilitates contact with APC and lymphocytes

What are vaccine side effects

• Vaccines must go through YEARS of trials before they are licensed for general use

• some symptoms still exist such as

  • Local reaction at the injection site

  • Fever

  • Allergies

  • other adverse reactions