Primary and Secondary Immunity

Primary Immunity – When first exposed to an antigen, the body usually takes several days to respond and build up a large supply of antibodies.  The number of antibodies will peak and then begin to decline. 

Secondary Immunity – The production of Memory B or T Cells allows the cell to recognize the antigen much quicker if it is introduced again so the body will often be able to destroy the invading antigen before its numbers become great enough to initiate symptoms.

Memory B cells rapidly divide and develop into plasma cells and the antibody levels in the body rise quickly and reach greater numbers.  Active immunity lasts as long as clones of memory B and memory T cells are present.

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Sources of Specific Immunity – resistance to a disease causing organism or harmful substance

  • Inborn Immunity – Immunity for certain diseases is inherited 
  • Acquired Immunity – immunity can be acquired through infection or artificially by medical intervention
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Natural Immunity – exposure to causative agent or antigen is not deliberate and occurs in the course of everyday living as exposure to a disease causing pathogen or allergen

  • Active Exposure – you develop your own antibodies – Immunity is long lived 
  • Passive Exposure – you receive antibodies from another source as infants receiving antibodies from mother’s milk.  This immunity is short-lived 

Artificial Immunity or Immunization – exposure to causative agent or antigen is deliberate 

  • Active Exposure – injection of causative agent that has been weakened or killed such as a vaccine and you develop your own antibodies  – Immunity is long lived
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Result of an initial immunization and a booster injection 

  • Passive Exposure  – injection of protective gamma globulin serum containing antibodies  that were developed by someone else’s immune system
  • This immunity is short-lived but immediate so it prevents full infection from developing in patients just exposed to serious agents when there is not time to develop active immunity from immunization 

Role of Antibiotics and Antivirals 

  • Antibiotics or antibacterials – group of medications used to kill bacteria by preventing them from dividing    There is concern about the extensive use of antibiotics resulting in resistant forms of bacteria and “superbugs”
  • Antivirals – group of medications used to treat viral infections but they cannot destroy the virus.  Rather they inhibit the virus from reproducing and developing. 

Cultured Antibodies 

  • Monoclonal antibodies – cloning of many copies of the same antibody which can be useful in fighting diseases because they can be designed specifically to only target a certain antigen, such as one that is found on cancer cells.

Immunity Disorders –  the Immune System can be under productive when it fails to recognize abnormal cells as cancerous cells or it can be over protective and cause other types of difficulties

Allergies

hypersensitivity of the immune system to relatively harmless environmental antigens – the immune system reacts to an outside substance that it normally would ignore

allergy types (food, dust, mold, seasonal), symptoms and signs (skin rash, itching, red bumps, sneezing).

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Asthma

an obstructive pulmonary disorder characterized by recurring spasms of muscles in bronchial walls accompanied by edema and mucus production which make breathing difficult

it causes the airways of the lungs to swell and narrow, leading to wheezing, shortness of breath, chest tightness, and coughing

Extrinsic, or allergic asthma, is more common (90% of all cases) and typically develops in childhood

Intrinsic asthma represents about 10% of all cases. It usually develops after the age of 30 and is not typically associated with allergies

Treatment – inhaler with medications as albuterol to open airways 

Autoimmune Disorder

a condition that occurs when the immune system mistakenly attacks and destroys healthy body tissue- more than 80 different types – the immune system can’t tell the difference between healthy body tissue and antigens.

The result is an immune response that destroys normal body tissues. This response is a hypersensitivity reaction similar to the response in allergic conditions

Examples of autoimmune ( or immune-related) disorders include Addison’s disease , Celiac disease – (gluten-sensitive enteropathy), Graves disease, Hashimoto’s thyroiditis, Multiple sclerosis, Myasthenia gravis, Pernicious anemia, Rheumatoid arthritis, Systemic lupus erythematosus, Type I diabetes                                                 

AIDS (acquired immune deficiency syndrome)

final stage of HIV disease, which causes severe damage to the immune system-caused by infection with human immunodeficiency virus (HIV).- HIV infects vital cells in the human immune system such as helper T cells, macrophages, and dendrite cells

Tissue Rejection – Foreign MHC Proteins

human immune system is designed to attack anything it doesn’t recognize –white blood cells recognize the body’s tissues by looking for a set of antigens on the surface of each cell o The most important of these make up the major histocompatibility complex (MHC)

  • Self-antigens – Major-histocompatibility complex (MHC) protein markers – Two groups
    • Class I MHC markers – displayed on all cells except RBCs
    • Class II MHC markers – displayed on mature B-cells, some T-cells, and antigenpresenting cell
  • When your immune system finds cells in your body that don’t show the right MHC proteins (foreign MHC proteins), it tries to destroy them-Doctors test the MHC of potential organ donors to find the best match

Blood typing

Blood typing problems – ABO System

The surface membranes of RBCs carry proteins that act as antigens in some recipients

  • Type A blood has A antigens only.
  • Type B blood has B antigens only.
  • Type AB blood has both A and B antigens present
  • Type O blood lacks both A and B antigens
  • Blood plasma contains antibodies to the blood types not present.
  • Exposure to foreign blood antigens results in agglutination or clumping of RBCs, prevents circulation of blood, and the RBCs burst
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Rh System problems

Another  important antigen used in matching blood types.Persons with Rh factor on RBC membrane are Rh positive; Rh negative lack the Rh factor protein.

Rh negative individuals do not automatically have antibodies to Rh factor but develop immunity when exposed to it.

Hemolytic disease of the newborn (HDN) can occur when mother is Rh negative and baby is Rh positive.

  • Mother is not exposed to infants blood unless baby’s RBCs leak across placenta; otherwise mother is only “inoculated” with small amount of baby’s blood (and Rh protein) at birth.
  • Mother builds up antibodies that are small enough to pass placenta and can destroy baby’s RBC; mother receives a booster at each baby’s birth; therefore danger to successive infants grows.
  • Problem is solved by giving the mother anti-Rh antibodies, usually after baby’s birth, that attack any of baby’s RBCs left in mother’s blood before mother can produce antibodies.

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