ImmunoprophylaxisImmunoprophylaxis

Dr. SuhailDr. Suhail

Why do we do this, when its raining?Why do we do this, when its raining?

ImmunoprophylaxisImmunoprophylaxis

Protection against infectious diseases Protection against infectious diseases (immunization) is acquired by the (immunization) is acquired by the individual either passively or actively:individual either passively or actively:

I- Passive acquired immunityI- Passive acquired immunity

II- Active acquired immunityII- Active acquired immunity

I- Passive acquired immunityI- Passive acquired immunity

Ready made Ab transferred to individual giving rapid Ready made Ab transferred to individual giving rapid protection and short lasting immunity:protection and short lasting immunity:

a-Naturally acquired passive immunitya-Naturally acquired passive immunity Occurs when Occurs when antibody are transferred from mother are transferred from mother

to to fetus ( (IgG ) or in colostrum (Ig A). ) or in colostrum (Ig A). b- Artificially acquired passive immunityb- Artificially acquired passive immunity Short-term immunization by injection of antibodies, Short-term immunization by injection of antibodies,

For examples:For examples: - - injection of antitoxic seruminjection of antitoxic serum for treatment of for treatment of diphtheria or tetanus.diphtheria or tetanus. - - injection of gamma globulininjection of gamma globulin that are not produced that are not produced by recipient's cells, to children with by recipient's cells, to children with

hypogammaglobulin hypogammaglobulin . .

II- Active acquired immunityII- Active acquired immunity

Individual actively produces his own Ab.Individual actively produces his own Ab.

Immunity develop slowly and long lasting due to Immunity develop slowly and long lasting due to development of development of immunological memoryimmunological memory::

a-Natural active acquired immunitya-Natural active acquired immunity The person becomes immune as a result of The person becomes immune as a result of

previous exposure to a live pathogen (Infection) previous exposure to a live pathogen (Infection)

b-Artificially active acquired immunityb-Artificially active acquired immunity A vaccine stimulates a primary response against A vaccine stimulates a primary response against

the antigen without causing symptoms of the the antigen without causing symptoms of the disease.disease.

VaccinationVaccination

--immunity against pathogens (viruses and against pathogens (viruses and bacteria) by using:bacteria) by using:

Live attenuatedLive attenuated KilledKilled Altered antigens Altered antigens that stimulate the body to produce antibodiesthat stimulate the body to produce antibodies

-Vaccines work with the immune system's -Vaccines work with the immune system's ability to recognize and destroy foreign ability to recognize and destroy foreign proteins (antigens)proteins (antigens)

DIFFERENCES BETWEEN ACTIVE AND PASSIVE IMMUNITY.Differences between Active and Passive Differences between Active and Passive

immunityimmunity

VaccinationVaccination VaccinationVaccination prevents and controls prevents and controls many many

diseases such as diseases such as cholera, , rabies, poliomyelitis, , poliomyelitis, diphtheria, tetanus, measles, and diphtheria, tetanus, measles, and typhoid fever

Vaccines can be:Vaccines can be:

a- a- Prophylactic (e.g. to prevent or (e.g. to prevent or ameliorate the effects of a future ameliorate the effects of a future infection by any natural or "wild" by any natural or "wild" pathogen

b- Therapeuticb- Therapeutic (e.g. vaccines against (e.g. vaccines against cancer are also being investigatedcancer are also being investigated

Vaccine.Vaccine.

Preparation of an antigenic material Preparation of an antigenic material used to induce immunity against used to induce immunity against pathogenic organisms – a dead or pathogenic organisms – a dead or attenuated form of the pathogen.attenuated form of the pathogen.

Types of vaccines:Types of vaccines:1-Killed vaccines:1-Killed vaccines: Virulent bacteria or viruss used to prepare these Virulent bacteria or viruss used to prepare these

vaccines may be killed by heat (60 °C) or by vaccines may be killed by heat (60 °C) or by chemicals (formalin, phenol or merthiolate), chemicals (formalin, phenol or merthiolate), examples: examples:

a-TAB vaccinea-TAB vaccine against entric fever (heat) against entric fever (heat)

b-Salk vaccineb-Salk vaccine against poliomyelitis (formalin) against poliomyelitis (formalin) c-Semple’s vaccinec-Semple’s vaccine against rabies (phenol) against rabies (phenol)

d-pertussis vaccined-pertussis vaccine against whooping cough against whooping cough (merthiolate) (merthiolate)

Types of vaccines:Types of vaccines:Killed vaccines:Killed vaccines: Do not stimulate local immunityDo not stimulate local immunity

Are short actingAre short acting

Do not stimulate cytotoxic T cell response in Do not stimulate cytotoxic T cell response in contrast to live attenuated vaccinescontrast to live attenuated vaccines

Are safe, can be given to pregnant woman and Are safe, can be given to pregnant woman and

immuno - compromised hostimmuno - compromised host

Are heat stableAre heat stable

Types of vaccines:Types of vaccines:2-Live attenuated vaccines:2-Live attenuated vaccines:

- Living m.o which have lost their virulence so do - Living m.o which have lost their virulence so do not produce disease but produce immunity.not produce disease but produce immunity.

-Stimulate both humoral and cell mediated -Stimulate both humoral and cell mediated immunity, local and systemic.immunity, local and systemic.

-Not given to pregnant women and -Not given to pregnant women and immunocompromised hosts (may cause immunocompromised hosts (may cause diseases)diseases)

-Heat unstable-Heat unstable

Types of vaccines:Types of vaccines:

- It is prepared by:- It is prepared by: a-repeated subculturea-repeated subculture under unsuitable under unsuitable conditions (chemical or media) conditions (chemical or media) e.g e.g BCGBCG vaccine against vaccine against T.BT.B and and 17 D17 D vaccine against vaccine against yellow feveryellow fever..

b-growing at high tempb-growing at high temp. (above optimum . (above optimum temp) e.g temp) e.g Pasteur anthraxPasteur anthrax vaccine vaccine c-selection of mutant strainsc-selection of mutant strains of low of low virulence virulence e.g e.g Sabin vaccineSabin vaccine against poliomyelitis. against poliomyelitis.

Types of vaccines:Types of vaccines:

3- Toxoids3- Toxoids

- It is prepared by detoxifying bacterial toxins. It is prepared by detoxifying bacterial toxins.

- bacterial exotoxins treated by formalin to bacterial exotoxins treated by formalin to destroy toxicity and retain antigenicity destroy toxicity and retain antigenicity

- e.g.diphtheria and tetanus toxoid.e.g.diphtheria and tetanus toxoid.

Types of vaccines:Types of vaccines:4- Microbial products4- Microbial products vaccines are prepared from bacterial products or viral vaccines are prepared from bacterial products or viral

components e. g:components e. g: a-Capsular polysaccharide vaccines are:a-Capsular polysaccharide vaccines are: - Poor immunogen in children below 2 years age - Poor immunogen in children below 2 years age e. g e. g H. influenzaH. influenza -do not respond to T cell independent antigens -do not respond to T cell independent antigens inspite of its generation of Ig Minspite of its generation of Ig M -produce anticapsular opsonizing antibodies-produce anticapsular opsonizing antibodies -examples-examples meningiococci, pneumococci and H. meningiococci, pneumococci and H. influenzainfluenza b-cellular purified proteins of b-cellular purified proteins of pertussispertussis

c- c- purified surface Ag of hepatitis B viruspurified surface Ag of hepatitis B virus d-influenza virusesd-influenza viruses

Types of vaccines:Types of vaccines:prepared by recombinant DNA technology for prepared by recombinant DNA technology for

improvement vaccines improvement vaccines e.g:e.g: a- subunit vaccinesa- subunit vaccines in which microbial polypeptides are isolated from the in which microbial polypeptides are isolated from the

infective material hepatitis B and influenza virusesinfective material hepatitis B and influenza viruses

B- Recombinant DNA-derived antigen vaccines:B- Recombinant DNA-derived antigen vaccines: in which Ag are synthesizing by inserting the coding in which Ag are synthesizing by inserting the coding

genes into E. coli or yeast cell as Hepatitis B Vaccine.genes into E. coli or yeast cell as Hepatitis B Vaccine.

C- Recombinant DNA avirulent vector vaccines:C- Recombinant DNA avirulent vector vaccines: in which the genes coding for the Ag is inserted into in which the genes coding for the Ag is inserted into

genome of an avirulent vector such as BCG vaccinegenome of an avirulent vector such as BCG vaccine

D-Synthetic peptide vaccines:D-Synthetic peptide vaccines: synthesis of short peptides that corrospond to antigenic synthesis of short peptides that corrospond to antigenic

determinants on a viral or bacterial proteins e.g cholera determinants on a viral or bacterial proteins e.g cholera toxins and poliovirus to produce Ab response.toxins and poliovirus to produce Ab response.

Combined immunization (Vaccination)Combined immunization (Vaccination)

-Immunization against diseases is recommended in -Immunization against diseases is recommended in combination (for young children) as :combination (for young children) as :

diphtheria, tetanus (lockjaw), and pertussis diphtheria, tetanus (lockjaw), and pertussis (whooping cough), given together (DTP).(whooping cough), given together (DTP).

measles, mumps, and rubella, give together as measles, mumps, and rubella, give together as MMRMMR

Haemophilus influenzae bHaemophilus influenzae b (Hib) with DTP (Hib) with DTP

influenzae binfluenzae b (Hib) with inactivated poliomyelitis (Hib) with inactivated poliomyelitis vaccine (IPV)vaccine (IPV)

influenza; and influenza; and Neisseria meningitidisNeisseria meningitidis (meningococcal meningitis). (meningococcal meningitis).

Principles of VaccinationPrinciples of Vaccination

General Rule

The more similar a vaccine is to the disease-causing form of the organism, the better the immune response to the vaccine.

Principles of VaccinationPrinciples of Vaccination

Self vs. nonselfSelf vs. nonself Protection from infectious diseaseProtection from infectious disease Usually indicated by the presence of Usually indicated by the presence of

antibodyantibody Very specific to a single organismVery specific to a single organism

Immunity

Principles of VaccinationPrinciples of Vaccination LIVE VACCINES:LIVE VACCINES:(i)(i) Have access to both MHC I & II Have access to both MHC I & II

pathways.pathways.(ii)(ii) Can induce both cytotoxic and helper T Can induce both cytotoxic and helper T

cells.cells.(iii)(iii) Produce better overall immune Produce better overall immune

response.response.(iv)(iv) Cannot be used in pregnant women Cannot be used in pregnant women

and immunocompromised hosts.and immunocompromised hosts.(v)(v) More expensive and need More expensive and need

refrigeration.refrigeration.(vi)(vi) Local immunity at the portal of entry.Local immunity at the portal of entry.

Principles of VaccinationPrinciples of Vaccination

Non-Living vaccines:Non-Living vaccines:

(i)(i) Cannot enter MHC class I.Cannot enter MHC class I.

(ii)(ii) Cannot induce cytotoxic T cellsCannot induce cytotoxic T cells