Immunity & the Immunity & the Immune ResponseImmune Response

I.I. ImmunityImmunity1.1. ImmunityImmunity is the ability to defend itself is the ability to defend itself

against pathogens, (such as against pathogens, (such as bacteria, bacteria, viruses, fungi, protozoans, toxins and viruses, fungi, protozoans, toxins and cancerous tumors) cancerous tumors)

2.2. Two forms:Two forms:a.a. NaturalNatural- not specific to a particular disease- not specific to a particular disease

i.i. Ex. Ex. MacrophageMacrophage- concentrated in lungs - concentrated in lungs and digestive system; ingesting and and digestive system; ingesting and digesting any pathogen they encounterdigesting any pathogen they encounter

b. b. AcquiredAcquired- body’s response to a specific - body’s response to a specific pathogenpathogen

i. i. passive acquired-passive acquired- results when a results when a person receives immunity from another person receives immunity from another human or animal (ex. Mother’s antibodies human or animal (ex. Mother’s antibodies being passed to baby through placenta)being passed to baby through placenta)

ii. ii. Active acquired-Active acquired- develops following develops following direct exposure to the pathogenic agentdirect exposure to the pathogenic agent

Stimulates the body’s Stimulates the body’s immune immune responseresponse

Immunizations/vaccinationsImmunizations/vaccinations are are special types of acquired immunity by special types of acquired immunity by being exposed to a modified pathogenbeing exposed to a modified pathogen

II. Immune ResponseII. Immune Response1.1. Pathogens are recognized as foreign Pathogens are recognized as foreign

because they have proteins that are because they have proteins that are different from oursdifferent from ours

2.2. Foreign proteins are called Foreign proteins are called antigensantigens and and they stimulate the they stimulate the immune responseimmune response

3.3. Immune response has 2 different Immune response has 2 different processes:processes:

a.a. Humoral (or anitbody-mediated) immunityHumoral (or anitbody-mediated) immunityb.b. Cellular (or cell-mediated immunity)Cellular (or cell-mediated immunity)

A. Humoral ImmunityA. Humoral Immunity1.1. Production of Production of B lymphocytes (or B B lymphocytes (or B

cells)cells)2.2. B cellsB cells respond to antigens by respond to antigens by

producing an antibody to form an producing an antibody to form an antigen-antibody complexantigen-antibody complex

3.3. ComplexComplex either targets the pathogen either targets the pathogen for phagocytosis, or prevents it from for phagocytosis, or prevents it from damaging healthy tissuesdamaging healthy tissues

B. Cellular ImmunityB. Cellular Immunity

1.1. Involves the production of Involves the production of T cellsT cells and and natural killer (NK)natural killer (NK) cells cells

2.2. These cells are These cells are cytoxiccytoxic and physically and physically attack ad destroy pathogenic cellsattack ad destroy pathogenic cells

III. Standard PrecautionsIII. Standard Precautions1.1. Health care workers are exposed to a Health care workers are exposed to a

large # of pathogens and can become large # of pathogens and can become infectedinfected

2.2. Nosocomial infection-Nosocomial infection- infection infection resulting from a pathogen in a hospitalresulting from a pathogen in a hospital

3.3. Cross infection-Cross infection- occurs when a patient occurs when a patient or worker acquires a pathogen from or worker acquires a pathogen from another patient or workeranother patient or worker

4.4. ReinfectionReinfection-gets the same pathogen -gets the same pathogen againagain

5. 5. Self inoculation-Self inoculation- occurs when a person occurs when a person becomes infected in a different part of the becomes infected in a different part of the body by a pathogen from another part of his body by a pathogen from another part of his or her own bodyor her own body

6. 6. OSHAOSHA ( (Occupational Safety and Health Occupational Safety and Health AdministrationAdministration) came about when HIV and ) came about when HIV and Hep B appeared in late 80sHep B appeared in late 80s Mandatory guidelines (aka Mandatory guidelines (aka Standard Standard

Precautions)Precautions) to ensure that all employees at to ensure that all employees at risk of exposure to bodily fluids are provided risk of exposure to bodily fluids are provided with protectionwith protection