IMMUNOLOGICAL
microbiological and immunological investigations
·
Definitions of Terms
·
Microbiology-study
of minute organisms that cannot be seen by naked eyes
·
Immunology-Study
of the body mechanism involved in disease prevention so that the body can
resist infections.
·
Bacteriology-Study
of bacteria
·
Virology-Study of
viruses
·
Mycology-Study of
fungi
·
Morphology-Physical
appearance of micro organism
·
Phagocytosis.-The
process of engulfing foreign substances in the body by use of specialized cells
and destroy it completely.
ACTIVITY:
Define the following terms:
Microbiology,Immunology,Bacteriology,Virology,Phagocytosis,Morphology,Mycology
Define the basic immunology
Immunology
is the study of body defence mechanisms. Its derived from latin word immunitas meaning freedom from. This
gives the basis of immunology.The mainfunction of immune system is to prevent
or limit infections by microorganisms.For example,
The first line of defence against
microorganism is the intact skin and mucosa membrane.
Describe types of immunity
The defence mechanisms in the body is
divided in two as:-
- Natural immunity(non-specific
- Acquired immunity(specific).
NATURAL
IMMUNITY(Non- specific)
This is the first line of the body defence
mechanism.
It consists of the following:-
a)Mechanical
barriers-This includes
skin, lining of the gut, mucosa of the respiratory tract and genital areas. Nasal hairs act as
filters.The action of coughing and sneezing removes the microorganism.
b)Chemical
barrier-These are
secretions that consists substances whish have anti-microbial actions.
Examples; lysosomes found in eyes, genital
areas, respiratory tract, The salty fatty
acid, sebam found in skin
secretions, blood, HCL in the
stomach and tissue components(complement).
c)Phagocytosis-This is when cells caslled phagoctytes
engulf and destroys an organism or other foreign bodies by digesting it with
enzyme lysosomes or phagocyte is attracted to the site of infection by a
chemical substance called to as chemotactic factor.Examples of phagocytic cells
include;Neutrophils circulating in
the body,macrophage in lympnodes,Histocytes in connective tissues,microgial cells in the brain, kupffer cells in the liver,monocytes in blood
d)Antimicrobials –These are commensal flora protecting the
body from infection by stopping growth of potential pathogenic organisms by:-
·
occupying
the attachment
·
site.competing
for essential nutrients
·
producing
substances anatagonistic to other bacteria e.g.colicines.
ACQUiRED
IMMUNITY(specific)
.This is the second line of defence
mechanism after the natural.It is divided into active acquired or passive acquired.
Active acquired immunity
This immunity can be Humoral(antibody
mediated) or cellular(cell mediated-B-and T -cells) or both
This is when the body responds to foreign
substance or microorganisms by producing antibodies.
The immunity is produced as a result of
antigenic stimulation.E.g. infections,Antibody or cell mediated(T and B
cells),vaccination.
Passive acquired immunity
This is when antibodies formed from another
human or animal are introduced into the
body.This gives the body protection against foreign substance or microorganism.
It occurs naturally with passage of certain
antibodies across the placenta to the foetus and also the transfer of maternal
antibodies in breast milk after birth.
HUMORAL
IMMUNITY
These are plasma protein circulating
antibodies. They are specifically attached to antigen(bacteria, virus and
cells).They are produced by B-cell. The antibodies produced are IgM,
IgG, IgD, IgE, IgA.
IgG
- Consist of one sub unit and has two Ag combining sites
- Found in blood and tissue spaces.
- Crosses placenta barrier
- Its pre-dorminant in the circulating system(major)
- Secondary line of protection
IgM
- Consists of 5 subunits
- Has 10
antigen binding sites
- Found in blood circulation
- Its the main antibody formed after infection(primary
response )
IgA
- Consists of 2 subunits with 4 antigen binding
sites
- Found in body secretions
IgE
- Found in tissue and little in blood
- Its found in high quantities in patients with
parasitic infection, asthma or allergic reactions
IgD
- Function is not clear.
- Found in leukemic patients
- Has short half life in serum
CELLULAR
IMMUNITY
Mediated by cell. The cells involved are:
- T-Cells-found in T-lymphocytes-
They are divided in to the following subsets;-
o
T-helper
cells
o
T-cytotoxic
cells
o
T-suppressor
cells
o
T-delayed
hypesensitivity cells
- B-cells.-found in body fluids
List the common
immunological/serological reactions
·
latex agglutination-Visible
clamping together of bacteria,cells or particles by an antigen combining with
its specific antibodies.
·
precipitation –This is a test
that involves reactions of soluble antigens. when it reacts with antibody it
forms insoluble deposits(precipitate)
·
Immune-chromatographic test
·
Flocculation- This is a test
that involves reactions of soluble antigens. when it reacts with antibody it
form loose clumps of
precipitate.(floccules)
Importance of immunological investigation
·
To
detect Antibodies that are responsible for an infection
List common disorders and conditions associated with serological test
·
Disorders:
-
·
syphilis
·
hepatitis;
·
Condition:
-
·
pregnancy
Key
Points
Types
of immunity
Natural and acquired
Humoral
Antibodies
IgG,IgM,IgD,IgE,IgA
List
the common immunological/serological reactions
·
latex agglutination
·
Flocculation tests
·
Immune-chromatographic test
Evaluation
ASK
STUDENTS TO:
- Define microbiology,Immunology,precipition
- List two types of immunity
- List 5 types of humoral antibodies
- Mention 2 cells involved in cellular immune
system
Comments
Post a Comment