Serology_and _Immune _System._Pdf12345678

**Serology** is the scientific study of serum and other bodily fluids, focusing primarily on the identification and measurement of antibodies in the blood. It is a crucial area in immunology, the branch of biomedical science that deals with the immune system. Serological tests are commonly used to diagnose infections, monitor immune responses, and screen for autoimmune diseases.

**The immune system** is the body's defense mechanism against pathogens, such as viruses, bacteria, fungi, and parasites. It consists of a complex network of cells, tissues, and organs working together to protect the body from infections and other diseases. The immune system can be broadly divided into two main types:

1. **Innate Immune System**: This is the body's first line of defense and includes physical barriers (like skin and mucous membranes), chemical barriers (such as stomach acid), and cellular defenses (including phagocytic cells like macrophages and neutrophils). The innate immune system provides a rapid but non-specific response to pathogens.

2. **Adaptive Immune System**: This system is more specialized and involves lymphocytes, such as B cells and T cells. B cells produce antibodies that target specific pathogens, while T cells can directly kill infected cells or help orchestrate other immune responses. The adaptive immune system has memory, allowing for a faster and more effective response upon subsequent exposure to the same pathogen.

**Antibodies**, or immunoglobulins, are proteins produced by B cells in response to an antigen (a substance recognized as foreign by the immune system). They play a critical role in identifying and neutralizing pathogens, and their presence in blood can be detected through serological tests. These tests are used to diagnose various conditions, including infectious diseases (e.g., HIV, hepatitis), autoimmune disorders, and to check for immunity to certain infections.

1. SEROLOGY and
IMMUNOLOGY

2. Pre-Test
•1. Who is the father of Immunology?
•A. Bordet
•B. Bovet
•C. Carrell
•D. Pasteur
• 2. What is the cell responsible for Immune
System?
• A. RBC
• B. WBC
• C. Platelet

3. •3. What is the specimen of Choice used
for Serological Test?
• A. Serum
• B. Plasma
• C. Whole blood
•4. What type of immunity that is present
at birth?
• a. Innate
• B. Specific

4. •5. GIT, GUT, RT are the system
classified into:
• a. First Line of Defense
• B. Second Line of defense
• C. Third Line of defense
•6. What are the cells responsible for
Phagocytosis
• a. PMN’s
• B. Platelets
• C. Lymphocytes

5. •7. What cell is responsible for Humoral
response?
• A. B lymphocytes
• B. T lymphocytes
• C. PMN’s
•8. What is the product of Humoral
Response?
• A. Antigen
• B. Antibodies
•

6. •9. What is the largest lymphatic organ?
• A. Liver
• B. Spleen
• C. Thymus
•10. What is the Significance of Immune
System?
• A. Beneficial and Detrimental
• B. Beneficial only
• C. Detrimental only

7. HISTORY
•Bordet Complement
•Bovet Antihistamine
•Carrell Organ Transplant
•Durham & Gruber Agglutination
•Erlich Ab formation( side chain
hypothesis)

8. •Father of Immunology – Louis Pasteur
•Graber & Williams -
Immunoelectrophoresis
•Isihazaka - IgE
•Isaacs and Lindenmann – Interferons
•Jenner - Smallpox vaccine
•Kraus - Precipitation
•Koch - TB research

9. •Landsteiner - ABO and RH
•Metchnikoff- Phagocytosis
•Porter & Edelman –Ig Structure
•Richet & Portier - Anaphylaxis
•Snell, Daussett, Bernaceff – HLA
•Theiler - Yellow fever
•Von Behring - Antitoxin/Ab’s.
•Wasserman - CFT Syphilis
• Yalow - RIA

10. SEROLOGY
•Study of non-cellular component of
blood.
•Study of sera and its corresponding
Antibodies.

13. IMMUNOLOGY
•Study of body defenses:
•1. Antigens and Antibodies
•2. Allergy and hypersensitivity
•3. Recognition and disposal of non-self

14. Significance of the
Immune System.
•I. Beneficial
•Protection from Invaders
•Elimination of Altered Self

15. •II. Detrimental
•
•Discomfort( Inflammation)
•Damage to self ( Autoimmunity)

17. IMMUNITY
•Natural immunity
is present at birth
and provides
protection against
disease and aids in
recovery from
disease. However, it
also provides the
basis for organ
rejection after
transplantation
•Factors involved in
natural immunity
include:
•Physical barriers,
such as skin and
mucous
membranes.
•Genetically
controlled
susceptibility and
nonsusceptibility to
certain diseases.

18. •Inflammation, which
involves a vascular
response and a
cellular response by
phagocytic cells.
•Acute-phase plasma
proteins, such as C-
reactive protein,
•haptoglobin, and
fibrinogen which are
produced in
response to injury
and aid in wound
healing.
•Lacks memory
•2’ exposure =1’
exposure

19. •Acquired or
specific immunity
•Not present at birth,
it results when
immunologic
memory and
antibody specific to
a foreign antigen
develop in response
to the antigen.
•Acquired immunity
may be active
(through
immunization or
disease) or passive
( through
transplacental
transfer). This type
of immunity involves
both cell-mediated
and humoral
immune response.

20. Immune Systems line of
Defense
•First Line (barriers)
•1. skin and mucous
membrane ( major
external barrier)
•2. Secretion ex:
tears, saliva
(lyzosyme- attacks
bacterial cell wall)
•3. Acidity of GIT and
Vagina. Acid pH
initiates the growth
of microorganism.
•4. Cilia lining the
respiratory tract.
•It propels dust and
microorganism to
propel outside.

21. •2
nd line of defense
•Soldiers of the body.
•1. phagocytosis-
process of engulfing
•A. neutrophils
•B. monocytes-
macrophages
•2. Inflammation and
fevers.( tissue
reaction)
•3. Natural
antimicrobial
substances
•E.g. Complement,
properdin, tumor
necrosis, resistance
factor, lyzosyme.

22. •Third line of
defense.
•1. Lymphocytes
•A. T lymphocytes
•B. B Lymphocytes
•2. Antibodies
•Soluble substances
secreted by plasma
cells.
•Immune Response
• The IR may be
roughly divided into
two components,
cell mediated and
humoral.

23. Humoral Immunity
•Involves
immunoglobulin
(antibody)
production by B
lymphocytes.
Complement can
also be considered
a humoral
component because
• it can be
activated by Ig.
•3 phases of
Humoral IR.
• 1. Antigen
elimination.
•2. The primary
response
•3. The secondary
response

24. •1. Antigen
elimination. This
phase is
accomplished by
phagocytosis. Most
injected antigen is
removed within
minutes., but
complete removal
may take months or
years.
•2. The primary
Response.
•After exposure to an
antigen, there is a
latent period of
approximately 5 to
15 days before
antibody appears in
the serum. The
antibody titer
increases, plateaus,
then decreases.

25. •IgM is the first
immunoglobulin to
appear. Although a
small amount of IgG
is made later, the
majority of
immunoglobulin
produced during a
primary response is
IgM.
•3. The secondary
response.
•A second or any
subsequent
exposure to the
same antigen elicits
a secondary
response. This time,
there is a rapid
antibody response,
usually within 2 to 4
days after antigen
exposure.

26. •IgG is the
predominant
immunoglobulin.
•The circulating
antibody titer is
much higher and
lasts longer than
that seen in the
primary response.
•CELL-MEDIATED
IMMUNITY
•It is especially
important in viral
and fungal
infections and in
infections caused by
acid-fast bacilli.

27. Cells and Tissues of the
Immune System
•Lymphoid System
•Primary/ Central
•Secondary/ Peripheral

28. Central/ Primary
•Are the sites for
generation and early
maturation of
lymphocytes
•Organs Involved:
•Bone Marrow
•Thymus

29. Peripheral/ Secondary
•Functions:
•1. Trap antigens
•2. Are the sites for
initiation of most
immune response.
3. Provide signals for
recirculation of
lymphocytes
•A. Lymph nodes
•B. Spleen
•C. Mucosa-
associated Lymphoid
Tissue

30. Lymphocytes

31. Cells and Tissues of the
immune system.
•A. T – lymphocytes
are derived from
cells in the bone
marrow. This subset
of lymphocytes
migrates to the
thymus, where they
mature and acquire
and
•express certain
surface antigens. T
lymphocytes are
responsible for cell
mediated immune
responses. They
exist in several
subpopulation with
specific functions.

32. •T cells travel from
the bone marrow to
the thymus for
maturation.
• Maturation and
selection occur in
the cortex; migration
to the medulla;
release of mature T
cells to secondary
lymphoid organs.

33. •1. T helper cells (T
H)
are CD4 positive
and produce the
lymphokines
interleukin-2(IL-2),
interleukin -3 (IL-3),
granulocyte-
monocyte colony-
stimulating
factor(GM-CSF),
and gamma
interferon(IFN-y).
•2. T- suppressor
cells ( Ts) are CD8
positive and
produce factors that
inhibit the action of
other T cells.

34. •3. Most cytotoxic T
cells(T
c) are CD8
positive. They
secrete
lymphotoxins and
release perforins,
which destroy cells
recognized as
foreign.
•4. Delayed- type
hypersensitivity T
cells are CD4
positive. They
secrete macrophage
chemotaxin and
macrophage
migration inhibition
factor (MIF)

35. •B. Mature B
lymphocytes secrete
immunoglobulin .
These cells develop
in the bone marrow
in adults and are
later localized also
in the spleen and
lymph nodes. There
are several
identifiable stages of
B-cell maturation.
•Both T and B stem
cell have terminal
deoxynucleotidyl
transferase (TdT).
Stem B cells also
have immune
response( Ir) gene
products, which are
major
histocompatibility
complex(MHC)
proteins.

36. •The pre-B cell is
characterized by
immunoglobulin
gene rearrangement
and the appearance
of heavy chains in
the cell’s cytoplasm.
•In the immune B cell,
light chain genes
are arranged, and
the light chains
appear in the cell’s
cytoplasm. Coupled
with the heavy
chains the light
chains form IgM,
which is confined to
the cell surface
(sIgM)

37. •Non-T, non-B
lymphocytes have
neither T-cell nor B-cell
markers and have been
classified as killer cells
(K), natural killer
cells( NK) and
lymphokines-activated
killer cells (LAK)
•It is unclear as to
whether they
represent separate
populations or are
the same cells with
different functions.

38. •K cells express
surface
immunoglobulin
receptors and lyse
target cells by
ADCC.
•NK cells play a role
in tumor host
defense, because
they have the ability
to recognize and
destroy tumor cells.
LAK cells use IL-2 to
help lyse tumor cells.
.. cytotoxic T cells
(TC cells) and
natural killer (NK)
cells are similar in a
way that they are
both Effective
against virally
infected cells

39. •Phagocytes play a
major role in the
immune system.
•Chemotaxis- is the
name of the process
by which phagocytic
cells are attracted to
a substance such as
a bacterial peptide.
1.
•.
Polymorphonuclear
leukocytes (PMN’s)
include eosinophils,
basophils, and
neutrophils.

40. •. Eosinophil
granules contain
antimicrobial agents.
•B. Basophil
granules contain
histamine and
heparin, which play
a role in
anaphylactic
reactions.

41. •The two major
populations of
neutrophil granules
are primary and
secondary granules.
•C. Primary granules
contain
myeloperoxidase
(MPO) and
lysozyme, which are
important
bactericidal agents.
•Secondary granules
also contain
lysozyme.
Neutrophils have
chemotactic
receptors, which
allow them to
respond to
chemotaxins
produced at sites of
inflammation.

42. Monocytes and
Macrophages

43. •Monocytes and
macrophages
•Function. As
circulating
monocytes respond
to chemotaxins,
they leave the
circulation and enter
the tissues, where
they are converted
to macrophages.
•These cells are
important in antigen
processing and
antigen presentation.

44. •Secreted products.
Macrophages
secrete products
that assist in the Ir.
•Interleukin 1 (IL-1)
stimulates T-cell
growth.
•Interleukin 6 (IL-6)
stimulates B cells.
•Tumor necrosis
factor (TNF) has
antitumor and
antibacterial activity
and stimulates
production of IL-1
and interferon.

45. •Endothelial
leukocyte adhesion
molecule ( ELAM-1)
plays a role in
diapedesis
• ( migration of cells
into tissues from the
circulation).
•Other cells involved
in antigen
presentation are:
•1.Dendritic cells
•2.Langerhans cells
•3. B lymphocytes

46. •Lymphoid tissues
are found
throughout the
entire body.
•Distribution
•Spleen
•Thymus
•Thoracic duct
•Lymph nodes
•Bone marrow
•Peyer’s patches
•Tonsils
•Appendix
•Concentration.
Although both T and
B lymphocytes can
be found in all
lymphoid tissues,
the highest
concentration of T
cells is found in the
thymus. The highest
concentration of B
cells is found in the
bone marrow.

47. Spleen
•Largest lymphoid
organ
•Functions:
•Produces mainly
erythrocytes and
small numbers of
granulocytes and
platelets.(lymphopoi
esis)

48. •Ig production
•Filtration of cellular
debris and antigens
from the blood.
•Destruction of worn
red blood cells.
•Extramedullary
hematopoiesis.
•Consists of Splenic
pulp: white and red
pulp. With marginal
zones.

49. Thymus

50. Thymus
•This is the only
discrete central
lymphoid organ in
humans.
•It produces only T-
lymphocytes
precursors and has
no lymphoid
nodules.
Only organ containing
Hassall’s
corpuscles.
Function:
T-lymphocytes
production.
Blood supply and
blood-thymus
barrier.
Hormone production

51. Lymph nodes
•These are the
smallest but most
numerous
encapsulated
lymphoid organs.
•They act as in-line
filters of the lymph,
removing antigens
and cellular debris
and adding Igs.

52. •Functions:
•1. Filtration of
lymph.
•2.Lymphocytes
production. ( T- as
effector and B
memory cells.)
•3. Immunoglobulin
production.
•Structures:
•Cortex, Medulla,
Paracortical zone,
lymphatic vessels,
sinuses and lymph
flow.

53. Peyer’s Patches, Appendix
•Clusters of lymphoid
nodules in the
lamina propria of the
small intestines.
•Classified as
unencapsulated
lymphatic
aggregates.

54. Tonsils
•These partially
encapsulated
lymphoid
aggregates contain
many lymphoid
nodules; They
underlie the mucous
membranes of the
mouth and pharynx
•Together with the
diffuse subepithelial
lymphoid tissue that
connects them to
form a ring, they
guard the common
entrance to the
digestive and
respiratory tracts.
•Palatine, pharyngeal
and lingual tonsils.