Vaccines work by activating the immune system through active immunization with live attenuated or killed pathogens. They provide long term immunity through memory B and T cells. Common types include killed/inactivated, attenuated, toxoid, recombinant, and DNA vaccines. Vaccines are manufactured through in vivo, in vitro, or chemical synthesis methods. Potential risks include vaccine strain infection, superantigen effects, and allergic reactions.

2. Active Passive
 Killed live or attenuated  Transfer of performed
organism injected which can antibodies
induce immune response
 Long term  Short term
 Immune system plays role  No role of immune system
 Ex-Hepatitis B vaccine  Ex- diptheria
Diphtheria-pertussis(acellular)- Hepatitis A &B
tetanus (DPaT) Measles
Inactivated (Salk) polio vaccine Rabies
(IPV)
Measles-mumps-rubella (MMR)
combined vaccine
Haemophilus influenzae (Hib) vaccine

3.  A vaccine is a biological
preparation that improves
immunity to a particular
disease. A vaccine typically
contains an agent that
resembles a disease-causing
microorganism, and is often
made from weakened or
killed forms of the microbe
or its toxins.
 Vaccine is a form of Active
immunization

4.  Edward Jenner-The term vaccine derives
from Edward Jenner’s 1796 use of the term cow
pox (Latin variolæ vaccinæ, adapted from the
Latin vaccīn-us, from vacca cow), which, when
administered to humans, provided them
protection against smallpox.
 Louis Pasteur- generalized Jenner's idea by
developing a rabies vaccine, and in the
nineteenth century vaccines were considered a
matter of national prestige, and compulsory
vaccination laws were passed.

5. The Mechanism
of a Vaccine
 In an ideal
scenario, whenever a
vaccine is first
administered, it is
phagocytized by an
antigen presenting cell
(APC).
 Recent research suggest
that it is particularly
important that the vaccine
be taken up by a dendritic
cell.
 This is because dendritic
cells play a key role in
activating T cells, which
become helper T cells (Th
cells).

6.  From there, the activated
Th cells goes on to activate
mature B-cells.
 These activated B-cells
divides into two cell
types, antibody-producing
plasma cells and, most
importantly, memory B
cells.
 Memory T-cells are also
established, however, they
usually have a shorter half-
life than memory B
cells, thus, they play only a
minor role in long-term
immunity.
 Usually, there are no
cytotoxic T-cells formed
whenever the body
responds to a vaccine.

7. Potential
Shortcomings
of Vaccines
 In some rare cases, a
vaccine may directly
activate a B cell, without
stimulation from Th cells.
 Such antigens are
known as T-independent
(TI) antigens.
 The problem with such
a response is that only
Ig-M antibodies are
produced and there are
no memory cells
established.
 Thus, such a vaccine
will be useless against
establishing immunity.

8. TYPES
Killed
Attenuated
Toxoid
Surface molecule
Recombinant
vector vaccine
DNA Vaccine
Multivalent
subunit Complex
Chimeric vaccine

9. Killed/Inactivated
Some vaccines contain
killed, but previously
virulent, micro-organisms that
have been destroyed with
chemicals, heat, radioactivity or
antibiotics.
Examples are the influenza
vaccine, cholera
vaccine, bubonic plague
vaccine, polio vaccine, hepatitis
A vaccine, and rabies vaccine

10. HEAT CHEMICAL
INACTIVATED
INACTIVATED
Heat inactivation is Chemical inactivation
generally unsatisfactory with formaldehyde or
because it causes various alkylating
extensive denaturation agents has been
of proteins; thus, any successful.
epitopes that depend on E.g.-Salk Polio vaccine
higher orders of protein
structure are likely to be
altered significantly.

11.  Microorganisms can be attenuated so that they
lose their ability to cause significant disease
(pathogenicity) but retain their capacity for
transient growth within an inoculated host.
 Attenuation often can be achieved by growing a
pathogenic bacterium or virus for prolonged
periods under abnormal culture conditions. This
procedure selects mutants that are better suited to
growth in the abnormal culture conditions and are
therefore less capable of growth in the natural
host.

12. pathogenic bacteria and virus mutants are sel
are grown in abnormal culture -ected

13. Toxoid
 Some species of
bacterial produce what
is known as exotoxins.
 Toxoid are vaccines
which consist of
exotoxins that have been
inactivated, either by
heat or chemicals.
 These vaccines are
intended to build an
immunity against the
toxins, but not
necessarily the bacteria
that produce the toxins.
 Some examples are
botulinum antitoxin and
diphtheria antitoxin

14. Recombinant  Clone the gene for major
vaccines/Surface surface antigen of hepatitis
molecule virus(HBsAg)
 Express in yeast cell
The gene encoding
any immunogenic
protein can be  Recombinant yeast cells are
cloned and grown in large fermenters
expressed in
bacterial, yeast, or
 Yeast cell
mammalian cells
using Recombinant
harvested, disrupted by
DNA technology high pressure
Example-
HepatitisB vaccine  Recombinant HBsAg
released& purified
 Produce Ab’s

15. Recombinant vector
vaccine
Genes that encode
major antigens of
especially virulent
pathogens can be
introduced into
attenuated viruses or
bacteria.
The attenuated
organism serves as a
vector, replicating
within the host and
expressing the gene
product of the pathogen.
Example -vaccinia
vector vaccine

16.  DNA vaccines consist of plasmids that contains genes
for certain types of antigens
 Plasmid DNA encoding antigenic proteins is injected
directly into the muscle of the recipient.
 Muscle cells take up the DNA and the encoded protein
antigen is expressed, leading to both a humoral
antibody response and a cell mediated response
 The fact that muscle cells express low levels of class I
MHC molecules and do not express costimulatory
molecules suggests that local dendritic cells maybe
crucial to the development of antigenic responses to
DNAvaccines
 Gene gun can also be used for administration

18. DNA VACCINE NON DNA VACCINE
 encoded protein is expressed  Artificial form
in the host in its natural form
 induce both humoral and  One type of immunity
cell-mediated immunity  No memory(only in
 cause prolonged expression
of the antigen, which some cases)
generates significant
immunological memory.
 Refrigeration is not required  Handling problem
for the handling and storage
of the plasmid DNA
 same plasmid vector can be  Can’t be reused
used for different vaccines

19.  Synthetic peptide vaccines
 Contain immunodominant B-cell and T-cell
epitopes.
 Works intra cellularly therefore effective in
CTL response
 There are number of innovative techniques are
being applied to develop multivalent vaccines
that can present multiple copies of a given
peptide or a mixture of peptides to the immune
system-:

20. Solid matrix–antibody
antigen
(SMAA) complexes
 Monoclonal antibodies
are attached to solid
matrix
Saturate the antibody
with desired antigen.
Complex formed can be
used as vaccine
 Induce both HIR and
CMI
 Particulate nature
therefore increased
immunogenicity
facilitating phagocytosis

21. Detergent
oDetergent +protein antigen ->1,2,3
oMixing protein and detergent and then
remove detergent from micelle
oThe individual proteins orient
themselves with their hydrophilic
residues toward the aqueous
environment and the hydrophobic
residues at the centre so as to exclude
their interaction with the aqueous
environment.
1.ISCOM-Immunostimulating
complexes (ISCOMs) are lipid carriers
prepared by mixing protein with
detergent and a glycoside called Quil A.
2.Liposome-Liposomes containing
protein antigens are prepared by mixing
the proteins with a suspension
of phospholipids under conditions that
form vesicles bounded by a bilayer.

22. Examples-influenza
virus
-measles virus
-hepatitis B virus
-HIV
fuse with the plasma
membrane to deliver the
antigen
intracellularly, where it
can be processed by the
cytosolic pathway and
thus induce a cell-
mediated response

23.  Chimeric vaccines usually consist of attenuated
viruses that have been engineered to carry
antigens from multiple types of pathogens.
 For example, the yellow fever vaccine YF17D
has been engineered to carry antigens from
HIV, different types of bacteria, malaria, even
cancer.
 The main adv.of a Chimeric vaccine is the
establishment of immunity against several
different diseases with one administration

24.  There are three main vaccine manufacturing
strategies:
 In-vivo
 In-vitro
 Chemical Synthesis
 Some vaccines can be produced using any one
of the three methods while for other
vaccines, only one method will work.

25. In-Vivo
In in-vivo
manufacturing, the
vaccine is produced
inside a living organism.
Embryonated Chicken
eggs are commonly
used, particularly in
producing flu vaccines.
Vaccines, such as anti-
idiotype, can also be
produced in lab
animals, such as mice.
There are even some
species of plant, such as
bananas, that have been
genetically engineered to
produce a vaccine.

26. In-Vitro
 Here, using
recombinant DNA
technology, vaccines can
be produced in yeast
cultures, bacterial
cultures, or cell cultures.
Recombinant
vaccines, such as
chimeric vaccines, are
produced in this manor.
Attenuated
virus/bacteria vaccines
can also be produced
this way.

27. Chemical
Synthesis
 Here, instead of using
biological systems to
produce a vaccine, a
vaccine can be produced
in a lab.
 Vaccines that utilize
synthetic peptides as
well as conjugated lipids
and polysaccharides are
manufactured this way.
 Usually, this method is
used in combination
with either in-vivo or in-
vitro production.

28.  The primary risk associated with vaccines, especially
vaccines that utilize live organisms, is that the vaccine
itself causes illness.
 This Happened with the orally administered Sabin
vaccine for polio, where some individuals became ill
and, in rare cases, even spread the illness to other
individuals who were not exposed to the vaccine.
 Another risk is that the vaccine may behave as a super
antigen and over stimulate the immune system.
 Yet a third risk is that some individuals may have an
allergic reaction to the vaccine, especially vaccines
produced in Embryonated chicken eggs and in
transgenic plants.