Traditional vaccines use weakened or killed pathogens to induce immunity, while new generation vaccines use purified subunits, toxins, viral proteins, or genetic material from pathogens. Traditional live attenuated vaccines replicate in the body to produce an immune response without causing disease, while killed vaccines contain inactivated pathogens and require multiple doses. New generation vaccines include subunit vaccines containing purified antigens, conjugate vaccines linking weak antigens to proteins, virus-like particles mimicking pathogens, and nucleic acid vaccines containing genetic material to stimulate immunity. These modern vaccines allow targeted immune responses without infectious agents.

1. TRADITIONAL AND NEW
GENERATION VACCINES
By KRISHNAPRIYA.P.C

2. VACCINES
• A preparation of causative agent of a disease which is specially
treated for use in vaccination, in order to induce or increase
immunity.
• Typically contains an agent that resembles a disease causing
organism, and often made from weakened or killed
microorganism or subunits.

3. • Vaccines are based on two key elements of adaptive immunity
that is specificity and memory.
• Stimulation of an individuals own immune system to produce
antibodies by administration of vaccine

4. HISTORY
• British physician Edward Jenner, who
in 1796 used the cowpox virus(Latin
variola vaccinia)to confer protection
against smallpox.
• In 1885 the French microbiologist Louis
Pasteur and Emile Roux developed the
first vaccine against rabies.

5. THE MECHANISM OF VACCINE
• Whenever vaccine is first administered, it is phagocytized by an
antigen presenting cell.
• Recent researches suggests that it is particularly important that the
vaccine taken up by dendritic cell.
• This is because the dendritic cell play a key role in activating T
cells, which become helper T cells.
• From there activated Th cells goes on activating mature B- cells
• These activated B-cells divides into two cell types, antibody
producing plasma cells and, most importantly, memory B-cells.

6. • Memory cells can remember previously encountered pathogen,
when actual pathogen enters secondary immune response takes
place.
• During secondary immune response, the body mounts a
quicker and more robust attack on the pathogen.
• Thus pathogen is cleared from the body

7. THE MECHANISM OF VACCINE

8. ADJUVANTS
• An adjuvant is a chemical substance that can be added to a vaccine
in order to enhance the immune response to the vaccine.
• Examples of adjuvants are:
1.Aluminium hydroxide and aluminium phosphate(Alum)
• Alum is an inorganic salt that bind to proteins and causes them to
precipitate.
• Whenever the alum/vaccine complex is injected into the body it
slowly dissolves, releasing the vaccine.
• Bacterial extracts can be added, which enhances the immune
response.

9. 2.Freund’s Adjuvant
• In Freund’s adjuvant, the vaccine is suspended in oil droplets
• When injected into the body, the vaccine slowly diffuses out of
the oil drop
• Bacterial antigens can be added in order to enhance immune
response
• No used in human because of the risk of severe inflammation.

10. TYPES OF VACCINE
1.Whole organism vaccine
2.Subunit vaccine
3.Nucleic acid vaccine

11. 1.WHOLE ORGANISM VACCINE
Vaccine currently in use consists of inactivated (killed) or live
but attenuated (avirulent) bacterial cells or viral particles.
a)Live attenuated
b)Killed organism vaccine

12. LIVE AND ATTENUATED VACCINE
• Live attenuated vaccines are created by weakening infectious
organisms that can still replicate and induce protective
immune responses without causing disease in the host.
• Vaccination with the live but attenuated organism generates an
immune response that protects the vaccinated person against
severe disease or even infection.
• Live attenuated vaccines use live organisms that have been
weakened so that they are avirulent, meaning they are unable
to cause disease

13. 1.Bacillus Calmette Guerin(BCG)
• It is a vaccine against tuberculosis.
• It is prepared from a strain of live attenuated Mycobacterium
bovis.
• Human tuberculosis is caused by Mycobacterium tuberculosis.
• Robert Koch first distinguished M.bovis from M.tuberculosis.
• Albert Calmette,a French bacteriologist, and his colleague
Camille Guerin, observed that M.bovis cultured in glycerin
bile potato mixture was less virulent than wild strain.
• Repeated subculture producing a strain that was sufficiently
attenuated to be used in vaccine.

14. BCG
• The BCG vaccine was first used in
humans 1921.
• The Health committee of League of
Nation adopted BCG in 1928.However it
was widely accepted only after World
War II.
• BCG is given as a single intradermal
injection after a tuberculin skin test

15. KILLED ORGANISM VACCINE
• An Inactivated organism vaccines or killed organism vaccines
is a vaccine consist from virus, bacterial or other pathogens
that have been grown in a specialized culture and then
completely killed by heat, radiation or chemicals
• It is no longer capable of replication in the host and to be
effective must contain much more antigen than live vaccines

16. • Inactivation of pathogen used in vaccines lead to destroy the
pathogen’s ability to replicate and causing diseases but still
keeps its antigenicity and because of this, the immune system
will recognized it and produce protective antibody against
them, they are less effective than attenuated vaccine in
inducing cell-mediated immunity and eliciting a secretory IgA
• Therefore the killed vaccine requires more than one dose or
multiple boosters to induce the immune response and the
people with immunodeficiency are advised to use inactivated
vaccine instead of attenuated vaccine.

17. POLIO VACCINE(SALK VACCINE)
• Poliomyelitis is a disease that may cause irreversible paralysis
• It is highly infectious viral disease
• The first effective polio vaccine was developed by Jonas Salk in
1952.
• The Salk vaccine is inactivated/killed poliovirus vaccine.
• The vaccine is clear,colorless,sterile suspension for subcutaneous
injection.
• IPV is based on three strains of polio virus(type1,2,3)originally
grown in monkey kidney cell culture and inactivated by exposure
to formaldehyde.

18. • In 1987,a new potent version of inactivated polio virus vaccine
was introduced, that is grown on human cell culture.
• IPV produce protective antibodies in the blood.
• After two doses, high levels of antibodies,to all three types of
polio virus appears in 94%-100% of individuals.
• The immunity prolonged and perhaps life long

19. 2.SUBUNIT VACCINES
• Subunit vaccines, like inactivated whole-cell vaccines, do not
contain live components of pathogen.
• They differ from inactivated whole-cell vaccines, by
containing only specific purified macromolecule derived
from the pathogen. These molecules are necessary to elicit a
protective immune response.
• Subunit vaccines are inactivated serotoxins or toxoids,
capsular polysaccharides or surface glycoproteins and key
recombinant protein antigen.
• Advantage of subunit vaccine is that they are non infectious
and elicit strong humoral response
• Disadvantage of subunit vaccines are antigens must be
produced and purifed by cultivation of pathogen, Multiple
doses typically required,adjuvants are needed

20. TOXOID VACCINE
• In some diseases like diphtheria and tetanus it is not growth of
the bacterium that is dangerous, but the protein toxin that is
liberated by it.
• Treating toxin with formaldehyde denatures the protein so that
is no longer dangerous.
• The inactivated toxins is called toxoid.
• Toxoid vaccine use toxoids as antigen to induce an immune
response.
• By using toxoid vaccines body is able to produce an immune
response against original toxin, but since the toxoid is
weakened form of the toxin it cannot lead to any toxicity or
toxin induced disease.
• Eg:Diphtheria and tetanus vaccines

21. RECOMBINANT PROTEIN VACCINE
• Vaccine produced by using recombinant DNA technology (i.e.
mixing of two DNA from different sources).
• Recombinant vaccines are those in which genes for desired
antigen are inserted into a vector, usually virus, that has very low
virulence.
• The vector expressing the antigen may be used as vaccine or the
antigen may be purified and injected as subunit vaccine.
• Hepatitis B virus vaccine (HBV)is an example of subunit
recombinant vaccine.

22. • Hepatitis B surface antigen is produced from a gene
transfected into yeast cells and purified for injection as a
subunit vaccine.
• This is much safer than using attenuated HBV, which could
cause lethal hepatitis or liver cancer if it reverted to its virulent
phenotype

24. CONJUGATE VACCINES
• Conjugate vaccine is produced by fusing a highly
immunogenic protein to a weak vaccine.
• Vaccine against haemophilus influenzae type b ,a major
cause of bacterial meningitis and infection induced deafness in
children is conjugate formation.
• It consist of a type b capsular polysaccharide covalently
linked to a protein carrier, tetanus toxoid.

25. • The polysaccharide-protein conjugate is considerably more
immunogenic than the polysaccharide alone, because it
activate TH cells, it enables class switching IgM to IgG
• Polysaccharide vaccine alone can only induce B cells,
whereas polysaccharide-conjugate vaccine can induce both B
and T cells.

26. VIRUS LIKE PARTICLE
VACCINE(VLP VACCINES)
• VLP stands for virus-like particles.
• Virus-like particles are molecules that mimic viruses but are
not infectious.
• They are a very effective way of creating vaccines against
diseases such as human papillomavirus (HPV), hepatitis B,
malaria,etc.
• A virus-like particle is not infectious because it does not
contain any viral genetic material. As they are very similar
to real viral molecules, introducing a VLP into the body will
trigger an immune response, but a person will not experience
any symptoms of the virus they are being vaccinated against.
• Once the body has had an immune response to the VLP, it will
recognize the virus and prevent infection in the future, giving
people immunity to that particular virus.

27. VLP

28. OUTER MEMBRANE VESICLE
VACCINES
• Outer Membrane Vesicles (OMVs) are
naturally produced by bacteria and are
essentially a bleb of the bacterial outer
cell membrane. This contains many of
the antigens found on the cell
membrane but is a non-infectious
particle.
• In the lab these OMVs can be harvested
from bacteria to use as vaccines.
• The OMVs can also be modified so that
toxic antigens are removed and antigens
suitable for stimulating an immune
response can be kept.
• OMVs also naturally act as adjuvants.

29. 3.NUCLEIC ACID VACCINES
• Nucleic acid vaccines use genetic material from a disease-
causing virus or bacterium (a pathogen) to stimulate an
immune response against it.
• Depending on the vaccine, the genetic material could be DNA
or RNA; in both cases it provides the instructions for making a
specific protein from the pathogen, which the immune system
will recognize as foreign (an antigen).
• Once inserted into host cells, this genetic material is read by
the cell’s own protein-making machinery and used to
manufacture antigens, which then trigger an immune
response.

30. DNA/RNA VACCINES
• DNA and RNA vaccines are third generation vaccines, and
are made up of a small, circular piece of bacterial DNA
(called a plasmid) that has been genetically engineered to
produce one or two specific proteins (antigens) from a micro-
organism.
• The vaccine DNA/RNA is injected into the cells of the body,
where the "inner machinery" of the host cells "reads" the
DNA/RNA and converts it into pathogenic proteins. Because
these proteins are recognized as foreign, when they are
processed by the host cells and displayed on their surface, the
immune system is alerted, which then triggers a range of
immune responses

31. Genetic Immunization:
• Since its early applications in the 1950's, DNA-based
immunization has become a novel approach to vaccine
development.
• Direct injection of naked plasmid DNA induces strong
immune responses to the antigen encoded by the gene vaccine.
• Once the plasmid DNA construct is injected the host cells take
up the foreign DNA, expressing the viral gene and
producing the corresponding viral protein inside the cell.
• This form of antigen presentation and processing induced both
MHC and class I and class II restricted cellular and humoral
immune responses

33. COVID 19
• In early December 2019, an outbreak of corona virus disease
2019 (COVID-19), caused by a novel severe acute respiratory
syndrome corona virus 2 (SARS-CoV-2), occurred in Wuhan
City, Hubei Province, China.
• On January 30, 2020 the World Health Organization declared the
outbreak as a Public Health Emergency of International Concern.
• The common symptoms of this disease are high fever, dry
cough, tiredness, loss of sense of taste or smell, muscle aches,
headache, sore throat, runny nose, vomiting, diarrhea, etc.
But serious patients may also experience acute shortness of breath
and pneumonia.
• SARS COV-2 spreads through close contact with an infected
person. This virus spreads when an infected person coughs,
sneezes, or talks.

34. COVID 19 VACCINES
• Currently, there are two COVID-19 vaccines available in India
- Covishield and Covaxin.
COVISHIELD
• Covishield is the Indian version of the Oxford AstraZeneca
vaccine.
• The Serum Institute Of India’s Covishield is a viral vector
vaccine for corona virus.
• Being a viral vector vaccine, it essentially uses a weakened
version of the very virus that it is battling.

35. • The Covishield contains a weakened version of the
adenovirus that is found in chimpanzees. It is also the
weakened form of the common cold virus that is found in
human beings. This weakened virus strain or viral vector also
has the genetic material of the SARS-CoV-2 spike protein.
• The science behind using a viral vector is that it will trigger
an immunological response which will in turn help prevent
the corona virus from harming the body.
• It will prepare the immune system to respond similarly in case
of such a virus attacking the body and develop an antigen.

37. COVAXIN
• Covaxin is a COVID-19 vaccine developed by Bharat Biotech,
an Indian biotechnology company, and the Indian Council of
Medical Research. Covaxin, also known as BBV152, is a type of
whole-virus vaccine called an inactivated vaccine.
• An inactivated vaccine incorporates a modified or dead version
of the virus, in this case SARS-CoV-2, which cannot replicate
and so cannot cause disease.
• The virus in an inactivated vaccine triggers an immune response
and causes the body to produce antibodies, equipping it to defend
itself against potential future infection.

39. QUESTIONS
1.The process of introduction of weakened pathogen into human
body is called
a)Immunization b)Vaccination
c)Attenuation d)none of these
2.The first vaccine produced against
a)Rabies b)small pox
c)Plague c)Tetanus
3.The concept of vaccination was first developed by
a)Louis Pasteur b)Edward Jenner
c)Carl Landsteiner c)Joseph Miester

40. 4.The process of weakening a pathogen is called
a)Vaccination b)Attenuation
c)Immunization d)virulence reduction
5.The first vaccine developed by Louis Pasteur was against
a)Pox virus b)hepatitis virus
c)Rabies virus d)none of these
6.A vaccine can be
a)An antigenic protein b)Weakened pathogen
c)Live attenuated pathogen d)All of these

41. 7.Passive immunization include
a)Introduction of antibodies directly
b)Transfer of maternal antibodies across placenta
c)Transfer of lymphocyte directly
d)All of these
8.Which of the following statement is true regarding vaccination?
a)Vaccination is a method of active immunization
b)Vaccination is the method of passive immunization
c)Vaccination is a method of artificial passive immunization
d)Vaccination is a method of natural passive immunization

42. 9.Active immunity may be gained by
a)Natural infection b)Vaccines
c)Toxoids d)All of these
10.Plasmids encoding antigenic protein from a pathogen that is
directly injected into the cells where it express constitute
a)Protein vaccines b)nucleotide vaccines
c)DNA vaccines d)recombined vaccines

43. ANSWERS
1.b
2.b
3.b
4.b
5.c
6.d
7.d
8.a
9.d
10.c