MOD3 Immunization and Tuberculin Testing

immunization

process by which resistance to an infectious disease is induced/augmented

what are antigens composed of

most antigens — protein

polysaccharides and combos of polysacc and proteins also exist

are bacteria and viruses antigens

yes

another name for antigen

immunogen

what cells are activated in the cellular immune system

T cells

what cells are activated in the humoral immune system

B cells

what do T cells produce 

lymphokines and memory cells 

what do B cells produce

specific antibodies IgM then IgG and memory cells

what are antibody molecules made up of 

proteins — grp of proteins called gamma globulins aka immunoglobulins 

what are the two types of immunoglobulins important in immunization

IgM and IgG

role of IgM in immunization

first and largest antibody

stays in blood stream where they encounter and inactivate foreign microorganisms

doesnt last long in host

presence indicates current or recent exposure to antigen

role of IgG in immunization

follows production of IgM

long lasting

presence ALONE indicates past exposure to antigen

present in blood and other body fluids — major part of humoral/fluid immunity of host 

plasma cells 

produce antibodies 

memory cells

dont currently produce antibodies, can be activated in the future

factors affecting response to immunization

• individual differences

• site of injection

• immunization product

• product failure

naturally acquired immunity 

• natural process — have disease

• maternal transfer of antibodies via placenta

• mother to newborn vis breast milk 

artificially acquired immunity 

antigen administered deliberately to induce immunity — needle, spray, oral

active immunity

• individual given/exposed to antigen — triggers response

• individual produces own antibodies

• takes days to weeks to establish protection

• used for disease prevention

• vaccines and toxoids

• long lasting immunity

passive immunity

• person given pre-formed antibodies post exposure to antigen

• antibodies available immediately to provide protection

• primarily for disease treatment or short-term prevention

• immune globulins, antitoxins, gamma globulin

• immunity doesnt last long — 3 months

vaccine

suspension of virus/bacteria altered to not cause disease, able to evoke response 

not pathogenic, but antigenic — can stimulate ab production 

toxoid

prepared by extracting bacterial exotoxin from a culture and treating it

no longer toxic but retains antigenic properties

passive immunization 

consist of pre-formed antibodies made in another person or animal

used for short-term disease prevention following exposure bcs antibodies are immediately available 

product given in active immunity

antigen

product given in passive immunity

antibody

use of active immunity 

disease prevention

use of passive immunity

disease treatment, short term prevention

why is rubella immunization important

prevent fetal infections and possible birth defects — can be transferred from mother to baby through placenta

elimination of the reservoir of the virus

immunization in newborns 

immune system isnt well developed 

first two months, wont respond effectively to antigen stimulation

protected by mothers antibodies 

becomes competent around 2m, maternal abs decrease

immunizations in healthcare workers

designed to protect the patient

all workers in AB must have immunity to rubella

other requirements determined by employer

what booster shot should adults get

tetanus-diphtheria Td toxoid every 10 years

where should heb b vaccines be injected into

deltoid muscle

site of injection for vaccines 

other sites may result in poor antibody response 

fatty tissue: vaccines may be bound in tissue and not stim ab production

factors contributing to poor antibody response

improper site of injection

poor mixing of vaccine

use of vaccine that has been frozen

when are protective levels of antibodies present

after third dose

tuberculosis 

major infectious disease — mainly now undeveloped countries 

most frequent cause of mortality due to a single pathogen 

slow growing organism with long generation time

incubation period — weeks to months

how to minimize risk of TB for healthcare workers

• recognize high-risk patients that may have TB

• understand how TB is spread

• use of TB skin testing

• use of anti-TB drugs when appropriate

how can TB be spread 

• direct contact

• droplet nuclei 

droplet nuclei with TB

greatest danger of being infected with TB

sputum and resp secretions expelled by pt dries in environment — formed microscopic particles, float freely in air

bacterium has waxy cell wall — allows it to stay viable

droplet may have enough live bacteria to infect

how to minimize exposure to airborne pathogens (TB)

special mask — HEPA filter or N95

not regular surgical mask

how are TB patients isolated 

isolation room with negative pressure 

air from room should be exhausted to the outside

what happens after TB bacterium is inhaled

90% infected but never has the disease — will not pass it on

5% have active disease — poor nutrition, crowded living, etc

5-10% infected but doesn’t develop active disease until later in life

symptoms of TB

persistent cough

fever

malaise

weight loss

reasons for a positive tb skin test 

• active case of tb

• pt has been in contact w and infected by bacteria — immune system effectively controlling

• pt has had an active case in the past

• pt has been immunized against tb

what can we do to confirm an active case of tb

doctor visit, chest xray, sputum culture