Overview Immuniology Flashcards
Immunology is the study of what?
The study of the ways the body resists infection
Innate Immunity
(Non-specific Immunity)
“you are born with it”
First Line Defense:
1.1 Skin – unbroken skin prevents microbes from entering the body
1.2 Mucous membrane with cilia in the respiratory tract – traps inhaled dust, dirt and pathogens
1.3 Digestive secretions of the stomach and intestines
1.4 Phagocytosis – neutrophils, eosinophils, macrophages, histocytes
1.5 Inflammatory Response – swelling, redness, heat and pain
- prevents the spread of the pathogen
- localize and contain the infection
- contain and neutralize the toxins
- to aid in the repair of damaged tissues
1.6 Peristaltic movement of the GI Tract
1.7 Flushing action of urination
1.8 Vaginal mucosal secretions
Second Line Defense
2.1 Complement – a group of plasma proteins that aid in the lysis of bacterial cells
2.2 Interferon – proteins produced by leukocytes, inhibits the spread of viral infection
- “interfere” withviral replicationwithin host cells
Acquired Immunity
(Specific Immunity) – “you acquire it” - immunity brought about by production of specific antibodies/cells that protect against pathogens
Antibodies
protective proteins produced by white blood cells as a reaction to the presence of an antigen
Natural Active Immunity
production of antibodies by the host after natural/non-deliberate exposure to the disease
Example: immunity against German measles after
having one
Artificial Active Immunity
antibody production by the host stimulated by deliberate exposure to the antigen (as in vaccination)
Natural Passive Immunity
naturally produced antibodies of one individual are passed on to another susceptible individual
Example: antibodies from the mother to the offspring through the placenta or through breast milk
Artificial Passive Immunity
antibodies from animals or human beings prepared in the laboratory (artificially produced) are injected to a susceptible individual
Example: commercially prepared anti-rabies antibodies injected to a patient after a bite from a potentially rabid animal
Types of Vaccines
- Live Attenuated Vaccine – contains live but weakened or less virulent forms of the pathogen
Example: measles vaccine * - Killed Inactivated Vaccine - contains non-living or inactivated pathogens
Example: Flu vaccine - Toxoids – contain toxins of the pathogen
Example: Tetanus vaccine - Extracts of pathogens (such as bacterial capsule of pathogens)
Example: Pneumococcal vaccine
attenuate
to weaken, to lessen the effect
Humoral Immunity an immune response
production of antibodies upon exposure to an antigen
Antibodies = Y-shaped protective proteins produced by white blood cells (B-Lymphocytes) as a reaction to the presence of an antigen
B-Lymphocytes or B cells – formed in the bone marrow and moves directly to the lymph nodes and spleen where they survey for invading pathogens
Cell-mediated Immunity an immune response
production of T- lymphocytes, macrophages and natural killer cells that directly attack pathogens and cancer cells.
T-lymphocytes or T-cells – formed in the bone marrow then migrate and mature in the thymus.
Process of Infection
*Generally do not cause disease
Resident Flora (Normal Flora)*– organisms that normally live in and on the bodies of healthy persons without causing harm when located in specific sites
Example: Staphylococcus – skin
Transient Flora* – organisms that take up residence in or on the body temporarily in a location where they are not normally found
Example: Escherichia coli – skin
Opportunistic organism – a resident organism that has multiplied way beyond its normal number and has caused disease
Opportunistic infections are likely to occur when host resistance is lowered
Example: Staphylococcal infection in a surgical site
Infection
An invasion of the body by organisms and the reaction of the body to the presence of those organisms and to the toxins they produce
The presence of and multiplication of an organism that results in harm or disease to a host
Disease - a specific illness or disorder characterized by a recognizable set of signs and symptoms
- attributable to infection, heredity, diet or environment
Host - an organism that serves as a permanent or temporary home for another organism
Example: Human host of a bacterial infection
Toxin - a substance that is harmful to host cells
Example: toxins from syphilis, tuberculosis, staphylococcus
Portals of Entry total 6
Specific pathways by which a microorganism enters the body that result in an infection
May be a natural opening (such as the mouth), or an injury (such as a cut, surgical incision)
- Skin – must be broken to act as a portal of entry
Examples: opportunistic staphylococcus, streptococcus, tetanus - Respiratory Tract – the most common route of infection
Examples: tuberculosis, pneumonia, common cold - Alimentary Tract – through the mouth by contaminated food or water
Examples: typhoid fever, hepatitis A, amoebic dysentery, cholera - Genito-urinary Tract – through the urethra and/or the reproductive tract
Examples: organisms causing UTI, STDs (gonorrhea, genital herpes, genital warts, HIV)
Urinary infections are usually the result of migration of microorganisms from the rectal area - Placenta – from mother to fetus
Examples: syphilis, HIV - Circulatory System – through the bloodstream by contaminated blood transfusion, needle pricks, cuts from contaminated objects, insect bites
Examples: Hepatitis B, HIV- insect bites: malaria, dengue fever
Portals of Exit
. Pathway by which microorganisms leave the body
. All body secretions and excretions (except for sweat) may be portals of exit
. Infections spread to others through portals of exit
- Respiratory secretions (sputum) – tuberculosis, pneumonia, common cold
- Saliva – streptococcal sore throat
Saliva from animals can be transmitted to humans
Example: rabies
- Blood - Hepatitis B, HIV
- a major concern for health care workers
- Feces - Hepatitis A, typhoid fever, amoebic dysentery
- Urine - typhoid fever, organisms causing UTI
- Semen and vaginal secretions – STDs
- Other portals of exit: tears, amniotic fluid, cerebrospinal fluid, vomitus, synovial fluid
Carriers
hosts who have recovered from a disease (or who are incubating the disease), who are asymptomatic, may still transmit the disease to others
Zoonosis
diseases that are communicable from animals to man
Factors Influencing the Occurrence of Infection
- Portal of Entry – most organisms cause disease only if they enter a particular pathway
Example: mycobacterium tuberculosis that enters through the respiratory tract can cause illness; the organism will not cause illness if it enters through the reproductive tract - Number of organisms – large numbers usually cause infection
- Virulence of the organism
Virulence is the relative power of a pathogen to cause disease.
An organism is more virulent if it creates toxins, harmful enzymes or with a capsule. - Resistance of Host - influenced by age, presence of underlying disease, immunosuppression, state of nutrition
Risk factors: extremes of ages, uncontrolled diabetes, cancer, malnutrition
Transmission of Pathogens
- Direct Contact –body contact between a carrier of the disease or one who has the disease and a healthy person (person-to-person spread)
- touching, kissing, sexual intercourse, across the placenta
- includes animal-to-person contact (example: rabies) - Indirect Contact – spread of disease by some medium other than direct contact with infected person
2.1 Fomites – inanimate objects freshly contaminated with secretions and excretions from an infected person or carrier – bedpans, drinking cups, bed sheets
2.2 Contaminated food and water
- Salmonella, amoebic dysentery, giardiasis
2.3 Vectors – an animal that transmits pathogens like mosquitoes, ticks, flies
- Malaria, Dengue Fever, Rocky Mountain Fever
2.4 Air microbes – sneezing, coughing, talking (common cold, influenza)
- droplet nuclei – minute drops of liquid from the nose or mouth which remain suspended in the air for a long time
Example: tuberculosis, measles, varicella
Stages of Acute Infection
- Incubation – period of time between entrance of organisms to the body and onset of symptoms in a host
- Prodromal – short period, usually a day or less, when the infection has been established but symptoms are not fully developed
- the host may not feel well but symptoms are vague - Acute – period of acute illness with symptoms; length will depend on the illness
- Convalescent - begins with decline of symptoms; length will depend on the severity of acute illness, treatment and general health of the host
TYPES OF INFECTION
Primary Infection – first or original infection
Secondary Infection – infection that follows or complicates the original disease
Mixed Infection – infection by more than one type of organism
Latent Infection – inactive, hidden, no apparent symptoms
Acute Infection – runs a rapid severe course and terminates abruptly
Chronic Infection – runs a slow course over a long period of time
Localized Infection – involves only one organ or site
Systemic Infection – has spread throughout the body
Health Care Associated Infection – contracted from a hospital or health-care facility
Primary Infection
first or original infection
Secondary Infection
infection that follows or complicates the original disease
Mixed Infection
infection by more than one type of organism
Latent Infection
inactive, hidden, no apparent symptoms
Acute Infection
runs a rapid severe course and terminates abruptly
Chronic Infection
runs a slow course over a long period of time
Localized Infection
involves only one organ or site
Systemic Infection – has spread throughout the body
Health Care Associated Infection
contracted from a hospital or health-care facility
ALLERGIC RESPONSE
. Altered antigen-antibody reaction in sensitized individuals caused by allergens
. Does not happen on first contact but with the second time person is exposed to the allergen
. Manifestations: itching, redness of skin, headache, difficulty in breathing
Treated with antihistamines, desensitization and avoiding the allergen
allergen
substance that brings on the manifestations of allergy ( dust, pollen, nuts, egg, chicken, sea foods, antibiotics)
ANAPHYLAXIS
. Severe Allergic Reaction that occurs suddenly and within minutes of exposure to allergen
. Usually due to a drug like penicillin or a foreign protein such as insect venom
. Manifestations: irritability, dyspnea (difficulty of breathing), cyanosis, unconsciousness, convulsions
. May be fatal
. Treated with epinephrine, antihistamines, corticosteroids, oxygen, intravenous fluids, respiratory support
Public Health
Endemic – a disease that is constantly present in a population but with involvement of a relatively few people
Epidemic - a disease that occurs in greater than normal incidence; an outbreak
Pandemic – a world wide epidemic
Endemic
a disease that is constantly present in a population but with involvement of a relatively few people
Epidemic
a disease that occurs in greater than normal incidence; an outbreak
Pandemic
a world wide epidemic
Disease
a specific illness or disorder characterized by a recognizable set of signs and symptoms
- attributable to infection, heredity, diet or environment
Host
an organism that serves as a permanent or temporary home for another organism
Example: Human host of a bacterial infection
Toxin
a substance that is harmful to host cells
Example: toxins from syphilis, tuberculosis, staphylococcus
Live Attenuated Vaccine
contains live but weakened or less virulent forms of the pathogen
Example: measles vaccine *
Killed Inactivated Vaccine
contains non-living or inactivated pathogens
Example: Flu vaccine
Toxoids
contain toxins of the pathogen
Example: Tetanus vaccine
Extracts of pathogens
(such as bacterial capsule of pathogens)
Example: Pneumococcal vaccine
Resident Flora (Normal Flora)*
organisms that normally live in and on the bodies of healthy persons without causing harm when located in specific sites
Example: Staphylococcus – skin
Transient Flora*
organisms that take up residence in or on the body temporarily in a location where they are not normally found
Example: Escherichia coli – skin
Opportunistic organism/infection
a resident organism that has multiplied way beyond its normal number and has caused disease
Opportunistic infections are likely to occur when host resistance is lowered
Example: Staphylococcal infection in a surgical site
What is the difference between B lymphocytes & Y shaped protective proteins
B-lymphocytes are formed in the bone marrow and move directly to the lymph nodes & spleen to patrol for invading pathogens.
While the antibody Y are produced by B-lymphocytes (white blood cells) because of a reaction to a found antigen.
