Fundamentals of Immunology for Pharmacy students

Miss Pradnya P Wadekar
Assistant Professor
ABCP, Sangli
Shivaji University, Kolhapur (MS)
India

 Definitions-pathogen, virulence,
attenuation, exaltation, antigens,
antibodies and antisera.
 Defense mechanisms of host –
 non-specific (skin and mucous membranes,
phagocytosis, complement system, inflammation, host
damage with exotoxins and endotoxins) .
 specific defense mechanisms - cellular immunity -
humoral immunity
 Immunity - types of immunity (natural, naturally acquired,
acquired (active and passive)
 Types and Structure of immunoglobulins
P P Wadekar, ABCP Sangli

 Pathogen: (Greek: Pathos- suffering and gen- produce)
disease producing.
 Pathogenecity: the capability to cause disease.
 Virulence: degree of pathogenecity
 Attenuation: decrease in virulence
 Exaltation: increase in virulence
 Antigens: any substance which when introduced in
host stimulate production of antibodies and react with
preformed antibodies if they are already present.
 Antibodies: are the immunoglobulins produced by
animal in response to introduction of antigen

 Antiserum: a blood serum containing antibodies
 Immunity: resistance offered by the host to the
harmful effects of pathogenic microbial infection.
 Susceptibility: lack of power of body to resist the
infection
 Immunology: study of immunity
 Immunological preparations: preparations used to
produce immunity

Defence mechanism of host
Natural resistance (
constitutive/ innate)
defence mechanism
Species racial Individual
External
defence
Internal defence mechanism
Non
specific
Specific

 Non specific defence mechanism
 Phagocytosis
 Natural killer cells
 Interferons
 Inflammatory response
 Fever
 Complement system

 Adherence is stimulated by
cations (Ca++ & Mg+) and
electrostatic forces
 Opsonin fixed attachment
 Formation of pseudopods
 Pseudopods fuse to form vacule i.e. phagosome.
 Lysosome granules move towards phagosome and fuse to
form phagolysozome
 In phagolysomes, bacteria are killed in minuts and
complete degradation takes place in hours.

 Major method of killing bacteria is respiratory burst
 It is associated with generation of highly toxic oxygen
species like superoxide, singlet oxygen, hydrogen
peroxide, hydroxyl radical also chloramines and
aldehydes.
 It also involves peroxidase ( in neutrophiles) and catalse (
in basophiles)
 The lysosome granules contain 60 enzymes- lysoszymes,
lipases, ribonuclease, etc.
 The combined action of respiratory burst and lysosome
granules kill bacteira
 Gram +ve are rapidly killed, gram –ve are more persistant
while some like Mycobacterium are resistant and can
actually multiply inside phagocyte

 Also called as “Null cells” since
they don’t posses certain surface
antigen
 They can kill cellular target without prior exposure to
anigen of target cell
 Thus they can kill cancer cells and virus infected cells
without ingesting them.
 The exact mechanism is still unknown.

 Are small proteins produced by
eukaryotic cells in response to
viral infection and double stranded RNA.
 3 types- α IFN, βIFN, γIFN
 Don’t react directly with virion
 Induce host cell to synthesize nonspecific antiviral protein.
 These are species specific.
 Purified Interferons are stable at low ph and fairly heat
resistant, but unstable at physiological conditions.
 Resist viral infections, inhibits cell proliferation, promot
cytotoxic activity of the NK

 Complement “C” refers to a system of factors which occur
in normal serum and are activated characteristically by
Ag-Ab interaction and subsequently mediate a number of
bilogically significant consequences.

 Consists of 11 proteins- C1 to C9 ( C1 is made of 3 sunits
C1q, C1r & C1s)
Site of synthesis Complement
protein
Intestinal epithelium C1
Macrophages C2, C4
Spleen C5, C8
liver C3, C6, C9

Activity Complement component
Lysis of virus, virus infected
cell, tumor cells, protozoa &
bacteria
C1-C9
Endotoxin activation C1-C5
Virus neutralization C1, C4, C2, C3
Anaphylotoxin release
Opsonization, enhancement of
cell mediated cytotoxicity,
stimulation of production of β
cell lymphocytes
C3b
Enhanced induction of Ab
formation
C3b, C3d
Chemotaxis of neutrophils,
eosinophils, monocytes
C5a

 Normally is in inactivated state but enzyme cascade-
preceeding component acts as enzyme on proceding
components cleaving them into dissimilar fragments.
 Larger framgents join the cascade while the small ones
contribute the defence mechanism by initiating the
inflammatory response, increasing vascular
permiability, inducing smooth muscle contraction ,
causing destruction of parasite, virus neutralization
and detoxification of endotoxins

 Properties of complement-
 Present in sera of animals, birds, fish
 Non specific serological agent
 Doesn’t increase the immunization
 Does’nt bind to free Ag/Ab
 Destroyed at 56C in 30 min
 IgM, IgG1, IgG2, IgG3 react with complent
 Classical pathway- 9 proteins
 Alternate ptahway- 13 proteins
 Activation of Ag-Ab complex

 Biological effects of complement-
 Causes bacteriolysis and cytolysis
 Complement fragments released during cascade
reaction amplifies inflammatory response.
 Participates in type II & type III hypersensitivity
reaction
 Lowered complement concentration on autoimmune
diseases
 C3 &C6 help in coagulation
 C bound to Ag-Ab complex adhere to erythrocyte
phagocytosis

 Is due to tissue injury, irritation initiated by entry of mos
or of other irritants
 Arteriols at the site constrict first and then dialate
increased blood flow at the site.
 Blood flow slows down increased amount of
leucocytes neutrophils get attracted by chemotactic
substances released at the site escape into tissue
phagocytosis.
Inflammatory response

 Rise in temperature
following infection if natural
defense mechanism
 Kills/ inhibits mos
 Also stimulate production of INFs

 The immunity developed by the individual during his
life time is known as acquired immunity
 It is by virtue of production of specific proteins i.e. Ab
against Ag

Activity immunity Passive imnunity
Ag containing preparation stimulates
activity
Ab containing preparation gives passive
immunity
Patient produces Ab Patient receives Ab
Immunity develops slowly Immunity develops quickly
Long lasting Temporary effect
Used for prevention of disease
(prophylaxis)
Used for short term prophylaxis and
therapeutically
Not applicable in immunodeficient host Appplicable in immunodeficient host
Negative phase may occur No negative phase
Immunological memory present No immunological memory
Cell mediated and humoral immunity is
involved
Exclusive humoral immunity is involved
No inheritance of immunity May be acquired from motherP P Wadekar, ABCP Sangli

 Local immunity: has importance in infections which
are either localised or where it is operative in
combating infection at the site of primary entry of the
pathogen.
 Eg- poliomyelitis, parentral vaccine systemic
immunity (Ab neutralise virus when it is in blood); but
cant prevent proliferation of virus at entry ie gut
mucosa. Hence live oral vaccine local immunity.
 Eg- live influenza virus administered intranasally
provides local immunity
 Herd immunity: over all level of immunity in country.
 It is relevant to control epidemic disease.

 Is due to lymphocytes.
 Are found in high concentration in lymph nodes,
spleen, and at the site where they are processed and
manufactured i.e. bone marrow and thymus.

Lymphoid organs
Primary/ central
organs
Thymus & bone
marrow
Secondary/
peripheral organs
Lymph nodes,
spleen, adenoids,
tonsils, appendix, etcP P Wadekar, ABCP Sangli

 Resistance against most extracellular bacterial pathogen
and viruses that attack respiratory and intestinal tract.
 B cells have Ab receptors which they are capable of
producing
 B cell is destined to produce only one Ab though it can
produce more than one class of Ab.
 B cell must receive a signal form interacting cell (T cell/
macrophage)in order to stimulate proliferation and
differentiation.
 A plasma cell secrets Ab and die after the function has been
served by it.
 A mature plasma cell can produce an unique class and
subclass Ig.

 Ab response to stimulation by Ag can be described as
Primary response and secondary response
5-10
days

 Negative phase is seen
 Memory/ booster/ anamnestic response
 Fisrt does is called priming dose, subsequent dose is
called booster dose

Priming dose Booster dose
•Priming dose and booster dose are imp in case of killed vaccines
•For live vaccines, single dose is sufficient as proliferation of mos
inside body provide continous stimulus that acts as both priming
and booster dose P P Wadekar, ABCP Sangli

 Involves T lymphocytes and macrophages
 Protects against fungi, viruses and intracellular
bacterial pathogens, intracellular parasites, rejecction
of foreign tissues grafts, delayed hypersensitivity and
resistance to some cancers
 Response starts with sensitization/ activation of T cells
against Ag activated T cells undergo prliferation
release lymphokines cytotoxicity and trigger
phagocytosis by macrophages.

 It is Y shaped, comprising of 4
polypeptide chains
 2 light chains (20000-25000 D &
213/214 amino acid residues) and 2
heavy chains(50000-70000 D &
446 amino acid residues)
 Upon reduction and acidification
Ab can yield 2 identical fragments
each with Ag binding fragment ie
Fab & one fragment which lacks
ability of binding with Ag ie
crystallizable fragment ie Fc which
has other properties like
complement fixation, placental
tranfer, skin fixaton and secretion
of body fluids.

 Ag binding site is at its amino
terminus while Fc fragment of
H chain has carboxy terminus
 Fd piece= protion of H chain
present in Fab
 Variable (V) region and
constant (C) region
 Amino acid sequence of varible
differs from that of C region
 Structure is flexible because of
hinge region, so might be T
shaped when not binding to Ab
 Polypeptide chains are folded
and held together by
disulphide bonds P P Wadekar, ABCP Sangli

 Compact globular
regions formed due to
folding are called
domains
 L chain has only 2
domains- VL and CL
 H chain has 4 domians-
VH and 3 Ch (CH1, CH2,
CH3)
 The portion between Ch1
and CH2 is hinge region

 5 classes- IgG, IgM, IgA, IgD and IgE

 Major serum Ig constituting about 80% of total Ig
 Is the only Ig traported across placenta
 Participates in most of the immunological reactions
like complement fixation, precipitation and
neutralization of toxins and viruses
 4 subclasses-
Subclass %
IgG1 70
IgG2 19
IgG3 8
IgG4 3

 Second most aboundant
class, 10-13% of total serum
Ig
 Major Ig present in tears,
saliva, seminal fliud, urine
and colostrum
 IgA is subclassified as IgA1
and IgA2

 Is monomeric molecule but in
mucosal surface and
secretions is dimer formed by
2 monomers joined together
by J (joining) chain.
 This called secretary IgA
(SIgA)
 SIgA contains glycerin rich
polypeptide called secretary
component or secretary piece
 secretary piece is believed to
protect IgA from denaturation
by bacterial protease
 SIgA is relatively resistant to
digestive enzymes and
reducing agents

 Molecular wieght-9,00,000 D
 Pentameric Ig protein
 5 monomeric units are held
together by disulphide bonds
anf J chian that connects H
chains
 It is synthesized in early
immune response
 It has short half life
 It binds to complement, is
acitve in agglutination and
opsonization

 Molecular wieght1,80,000 constitute 1% of tatal serum
Ig
 It is present on surface of B lymphocyte which
differentiate in to Ab secreting plasma cells
 It is chiefly produced in lining of respirator and intestinaly tracts
 It is present in extreamly low concentratioon in serum
 It mediates Prausnitz-Kustner reaction
 In involved in protection against pathogen by mast cell
degranulation and release of inflammatory mediators

 Ag-Ab reaction in vitro are known as serological reaction
 characteristics of Ag-Ab reactions:
 Reaction is highly specific, cross reaction may occur due to
similarity in Ag
 No denaturation during reaction
 Combination occurs at surface and hence surface antigens
are immunologically relevant
 Combination is firm but reversible
 Entire molecule reacts not the fragment
 Both Ag and Ab participates in formation of
ppt/agglutinate and they may combine in varying
proportion

 Ag-Ab react form lattice
that eventually results
into ppt
 Flocculation
 Prozone, zone of
equivalence and post
zone

 Similar to pptn
 Agglutination= visible
clumping
 Occurs when Ag and Ab react in equivalent proportion
 False negative agglutination may occur

 Anathanarayan and Panikar’s Textbook of
Microbiology, Seventh edition, Orient Longman
Publication
 Microbiology, Pelzar, Chan, Krieg, Fifth edition, Tata
McGaw Hill publication
 Pharmaceutical Microbiology- Principal applications,
Dr. Chandrakant Kokare, Nirali ppublication
 www.google.com

Fundamentals of Immunology for Pharmacy students

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

En vedette

En vedette (8)

Similaire à Fundamentals of Immunology for Pharmacy students

Similaire à Fundamentals of Immunology for Pharmacy students (20)

Plus de Pradnya Wadekar

Plus de Pradnya Wadekar (8)

Dernier

Dernier (20)

Fundamentals of Immunology for Pharmacy students

Notes de l'éditeur