SEROLOGY SECTION Flashcards
• Immunology - study of individual’s reactions when foreign
body is introduced
• Immunity - state of being protected or resistant from
infectious disease.
• Antigen - foreign
non-self substance bound by an
antibody molecule. May range from small
simple
intermediary metabolites (lipids
sugars
complex macromolecules (carbohydrates
proteins
acids). Not necessary to invoke immune response.
Immunogens - antigens that stimulate immune response
: Antibody - protein (immunglobulin) round in blos
plasma
produced by plasma cell derived from B
lymphocytes
response against a specific antigen.
Five types: IgG
IgM
Serology - division of immunology specialized in
laboratory detection and measurement of specific antibody
as response to an antigen. In-vitro reactions.
History of Serology
• Thucydides
Outbreak in Athens
430 BC. Found out that people
previously had the plague could only nurse the sick
• Ancient China
Started variolation or insufflation for smallpox
- Variolation - inhalation of dried crusts of smallpox
Smallpox - caused by Variola virus
plague of 13th
and 17” century
characterized by fever
filled with pus and fluid.
• Ancient England
- Variolation method is wounding the patient and putting
the pus from smallpox carrier to the wound site.
• Edward Jenner
Started the practice of vaccination (vacca
meaning
“cow”) against smallpox
- Sarah Nelms - milkmaid that had cowpox from her
cow Blossom and was immune from smallpox
- James Phipps - son of Jenner’s gardener that was
inoculated by cowpox lesions of Nelms by Jenner
then was introduced smallpox lesion. He developed a
reaction at the inoculation site but showed no signs of
smallpox
• Louis Pasteur
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- Coined the term vaccine and first to observe
attenuation
- Attenuation - process of making something weaker.
- First to demonstrate attenuation of a pathogen and
administer this attenuated strain as vaccine
- Succeeded in growing Pasteurella multocida
bacterium causing fowl cholera in culture
and
chickens injected cultured bacterium developed fowl
cholera
- Observed that old cultures injected was not the cause
of the cholera
and injected chickens were becoming
immune when injected with fresh culture of bacterium
- Proved that aging would lower the virulence (ability
to cause disease) of a causative agent
thus injecting
this attenuated strain is a protection against disease.
- Named the attenuated strain vaccine after Jenner’s
cowpox inoculation
- Vaccine - suspension of weak/inactivated/attenuated
cells or microorganisms to induce immunity
- First to vaccinate sheep using heat-attenuated
anthrax bacillus
- Injected untested rabies vaccine to a 9-year-old boy
named Joseph Meister
who was mauled and beaten
by a rabid dog. Treatment lasted for 10 days and the
boy was recovered.
Because attenuated viruses cannot be cultured
without a host
Pasteur injected live rabies virus in
rabbits in order for them to multiply.
Emil Roux - tested rabies vaccine to dogs and
observed vaccinated animals were immunized from
rabies exposure.
Humoral and Cellular Immunity
Emil von Behring and Shibasaburo Kitasato
Serum from animals immunized to diphtheria could
transfer immunity to unimmunized animals
• Elvin Kabat
-
A fraction of serum called gammaglobulin (now
immunoglobulin) is responsible for immunity. Believed
that humors or body fluids mediated by antibodies was
solely responsible of certain diseases and immunity
it
was called humoral immunity
• Eli Metchnikoff
Observed that WBCs
termed as phagocytes
able to ingest microorganisms (phagocytosis)
therefore concluded that cells contributed in immunity
of an animal
and became the first proponent of
cellular immunity
• Merril Chase
Transferred WBCs against Mycobacterium
tuberculosis to guinea pigs
reinforcing claims of
cellular immunity.
• Improved Cell Culture Techniques in 1950’s
Lymphocyte was identified as both responsible for
humoral and cellular immunity
• Bruce Glick
Performed experiments on chickens and identified two
types of lymphocytes
T Cells derived from thymus
and B Cells from bursa of Fabricious of the chicken
- Mnemonic for lymphocytes responsible for what
immunity: Tatay Co nasa Barangay Hall
> In humans
both B and T lymphocytes are produced in the
bone marrow. Immature T lymphocytes migrate to thymus
for maturation and B lymphocytes mature in the bone
marrow
Innate and Adaptive Immunity
Innate or Native Immunity
Cellular and biochemical defense mechanisms already
placed before infection
prepared in case of infection
- Response is the same for all pathogens/foreign
substances
No prior exposure is required
Response doesn’t change with subsequent exposures.
• Adaptive or Acquired Immunity
Produced after introduction of antigenic challenge to a
host
- Ability to remember prior exposure
resulting to
increased response in repeated exposure
- Characterized by specificity for each individual
pathogen or microbial agents
Two types of adaptive immunity
a.
Cellular immunity - mediated by T
lymphocytes
principal defense against
intracellular microbes
responsible in killing
infected cells.
b.
Humoral immunity - mediated by antibodies
produced by plasma cells derived from B
lymphocytes
principal defense against
extracellular microbes
Lines of Defenses
Anatomic barriers: skin
mucous
membranes
Physiologic processes:
sneezing
coughing
reflex
diarrhea
epithelium
First
Line of
Defense
Normal microbiota/flora:
healthy
nonpathogenic bacteria
found in respiratory tract and
intestines
INNATE
IMMUNITY
Secretions: tears
mucus
cerumen
saliva
sweat
stomach acid
Second
Line of
Defense
Very low pH of vagina and
stomach
Phagocytes: Neutrophils
Monocytes/Macrophages
NK
cells
Inflammatory reaction
ADAPTIVE
IMMUNITY
Third
Line of
Defense
ACTIVE
immunity
host makes
own
antibodies
Natural
Complement System: assisting
phagocytes in clearing foreign
bodies
promotes inflammation
Cellular components:
Lymphocytes - T (helper &
cytotoxic) lymphocytes
B
lymphocytes
Plasma cells
Humoral components:
antibodies and cytokines (protein
secreted by immune cells to
mediate and regulate immunity)
Antibody
produced
Infections
by host?
Duration
immune
response
YES
LONG
Artificial
Vaccination
PASSIVE
immunity
Antibodies
are passed
from donor
to host
Natural
Colostrum
(mother’s milk)
NO
SHORT
Artificial
Infusion of
serum/plasma
Routine Tests in Serology
- Non-Treponemal Antibody Tests
- Usually for detection of Syphilis (Treponema
pallidum)
-
Detects presence of reagin antibodies against
cardiolipin
Cardiolipin - found in mitochondrial membrane.
When membrane breaks
cardiolipin is secreted
triggering production of regain Abs
Although seen in syphilis patients
regain antibodies
are not specific in syphilis only as it is also observed
in infectious diseases such measles
Tb
leprosy
malaria
Includes: Rapid Plasma Reagin (RPR) Test and
Venereal Disease Research Laboratory (VDRL)
Test
- HBsAg (Hep. B Surface Antigen) Test
Detects infection of Hepatitis B virus by presence of
HBsAg. Indicative of being infectious of a patient.
- Anti-HBs (Hep. B Surface Antibody) Test
- Detecting presence of Anti-HBs
sign of being immune
from Hepatitis B virus.
- Production of Anti-HB is observed from vaccinated
persons and patients recovered from Hepatitis B.
- Widal Test
Detection of presence of antibodies against disease
causing Salmonella organisms (most known is
Salmonella typhi) which further diagnoses enteric and
typhoid fever.
- Dengue IgG/IgM Test
Screening test for dengue viral infection and aid in
differential diagnosing of primary and secondary
infection
- IgG - first to respond
IgM - responsible for
memory/anamnestic response
Results reads:
IgG positive ONLY: past dengue infection
• IgM positive ONLY: primary (first-time) infection
• BOTH IgG and IgM positive: secondary (second-
time) infection
- Dengue NS1 Test
Detects non-structural protein NS1 of dengue virus.
NS1 antigen is detectable in the acute phase of
dengue infection
especially in the first 7 days of
symptoms
- Dengue Duo Kit
Contains both dengue IgG/IgM and NS1 antigen tests.
