ant vaccines wrf hepatitis b final

8/8/2019 ant Vaccines Wrf Hepatitis b Final

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So far a large number of recombinant immunogenic proteins of pathogens have been

produced and evaluated. In general, a majority of such proteins are ineffective or only poorly

effective in immunization.

EXAMPLES OF RECOMBINANT VACCINE:

GARDASIL: for HPV infection which causes genital warts and cervical cancer.

LYME DISEASE VACCINE (recombinant OspA)

MEASLES,MUMPS AND RUBELLA VACCINE LIVE

HEPATITS B VACCINE:a preparation of HEP B surface antigen,derived either from

human plasma of carriers of HEP B or from cloning in yeast cells(hepatitis b virus).It

is the only licenced recombinant vaccine.

HEPATITIS

Hepatitis is an inflammation of the liver. It is usually caused by viral infections, toxic agents or drugs but

may be an autoimmune response. It is characterised by jaundice, abdominal pain,liver enlargement

and sometimes fever.

The different types of VIRAL hepatitis are A (formerly calledinfectious hepatitis), B (serum hepatitis), C (formerly called non-A,

non-B hepatitis), D (delta hepatitis), E (a virus transmitted throughthe faeces of an infected person), F, G, cryptogenic (Caused by avirus as yet unidentified).

Characteristics of Hepatitis Viruses

Hepatitis

A Virus

Hepatitis

B Virus

Hepatitis

C Virus

Hepatitis

D Virus

Hepatitis

E Virus

Nucleic acid RNA DNA RNA * RNA

Serologic

diagnosis

IgM anti-

HA

HBsAg Anti-HCV Anti-

HDV

Anti-HEV

Major

transmission

Fecaloral Blood Blood Needle Water

Incubation

period (days)

1545 40180 20120 30180 1460

Epidemics Yes No No No Yes

Chronicity No Yes Yes Yes No

Liver cancer No Yes Yes Yes No

IgM anti-HAV = IgM antibody to hepatitis A virus; HBsAg = hepatitis B

surface antigen; anti-HCV = antibody to hepatitis C virus; anti-HDV =

antibody to hepatitis D virus; anti-HEV = antibody to hepatitis E virus.

*Incomplete RNA; requires presence of hepatitis B virus for replication.


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HEPATITIS-B:

It is a serious disease caused by a virus that attacks the liver. Thevirus, which is called hepatitis B virus (HBV), can cause lifelonginfection, cirrhosis(scarring) of the liver, liver cancer, liver failure,and death.

HBV is a bloodborne pathogen, transmitted by percutaneous orpermucosal (e.g., sexual) exposure to infectious blood or bodyfluids (e.g., semen or saliva).HBV circulates in high titers in theblood and lower titers in other body fluids (e.g., semen, vaginalfluid, or saliva), and is approximately 100 times more infectiousthan HIV and 10 times more infectious than HCV.

Hepatitis B virus is an important cause of viral hepatitis. There is no specifictreatment for this disease.The incubation period for hepatitis B is relatively long; sixweeks to six months may elapse between exposure and the onset of clinicalsymptoms. The prognosis following infection with hepatitis B virus is variable anddependent on at least three factors: (1) Age Infants and younger children usuallyexperience milder initial disease than older persons;1 (2) Dose of virus The higherthe dose, the more likely acute icteric hepatitis B will result;1 and, (3) Severity ofassociated underlying disease Underlyingmalignancy or pre-existing hepaticdisease predisposes to increased morbidity and mortality.

HBV is a 42nm, double-shelled deoxyribonucleic acid (DNA) virus ofthe class Hepadnaviridae.

The outer surface membrane contains hepatitis B surfaceantigen(HBsAg), which also circulates in blood as 22-nm spherical

and tubular particles.


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The inner core of the virus contains hepatitis B core antigen(HBcAg),hepatitis B e antigen (HBeAg), a single molecule of partially double-stranded DNA,and DNA-dependent DNA Polymerase.

HEPATITIS- B VACCINE:

Hepatitis B is given as a series of three intramuscular doses, 0,1 and 6

intramuscular injections for population at risk.

ENGERIX B (Glaxosmithkline) ,RECOMBIVAX HB(Merck & co.) and

GENEVAC B(Serum institute of India)are the three typical vaccinesdeveloped for hepatitis b.

RECOMBIVAX HB:

RECOMBIVAX HB* Hepatitis B Vaccine (Recombinant) is a non-infectious subunitviral vaccine derived from hepatitis B surface antigen (HBsAg) produced in yeastcells. A portion of the hepatitis B virus gene, coding for HBsAg, is cloned into yeast,and the vaccine for hepatitis B is produced from cultures of this recombinant yeaststrain according to methods developed in the Merck Research Laboratories.The antigen is harvested and purified from fermentation cultures of a recombinant

strain of the yeast Saccharomyces cerevisiae containing the gene for the adwsubtype of HBsAg. The fermentation process involves growth ofSaccharomyces


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cerevisiae on a complex fermentation medium which consists of an extract of yeast,soy peptone, dextrose, amino acids and mineral salts. The HBsAg protein isreleased from the yeast cells by cell disruption and purified by a series of physicaland chemical methods. The purified protein is treated in phosphate buffer withformaldehyde and then coprecipitated with alum (potassium aluminum sulfate) to

form bulk vaccine adjuvanted with amorphous aluminium hydroxyphosphate sulfate.The vaccine contains no detectable yeast DNA but may contain not more than 1%yeast protein. The vaccine produced by the Merck method has been shown to becomparable to the plasma-derived vaccine in terms of animal potency (mouse,monkey, and chimpanzee) and protective efficacy (chimpanzee and human).The vaccine against hepatitis B, prepared from recombinant yeast cultures, is free ofassociation with human blood or blood products.Each lot of hepatitis B vaccine istested for sterility.RECOMBIVAX HB is a sterile suspension for intramuscular injection. However, forpersons at risk of hemorrhage following intramuscular injection, the vaccine may beadministered subcutaneously.

RECOMBIVAX HB Hepatitis B Vaccine (Recombinant) is supplied in threeformulations.Pediatric/Adolescent Formulation (Without Preservative), 10 mcg/mL: each 0.5mL dose contains5 mcg of hepatitis B surface antigen.Adult Formulation (Without Preservative), 10 mcg/mL: each 1 mL dose contains10 mcg ofhepatitis B surface antigen.Dialysis Formulation (Without Preservative), 40 mcg/mL: each 1 mL dosecontains 40 mcg ofhepatitis B surface antigen.All formulations contain approximately 0.5 mg of aluminum (provided as amorphousaluminumhydroxyphosphate sulfate, previously referred to as aluminum hydroxide) per mL ofvaccine. In eachformulation, hepatitis B surface antigen is adsorbed onto approximately 0.5 mg ofaluminum (provided asamorphous aluminum hydroxyphosphate sulfate) per mL of vaccine. The vaccine isof the adwsubtype.RECOMBIVAX HB is indicated for vaccination of persons at risk of infection fromhepatitis B virus

including all known subtypes. RECOMBIVAX HB Dialysis Formulation is indicated forvaccination of adultpredialysis and dialysis patients against infection caused by all known subtypes of

hepatitis B virus.

CHRONIC AFFECT OF HEPATITIS B ACROSS THE WORLD:

Hepatitis B is one of the world's major health problems. By recent estimates, more than 2

billion people are infected with hepatitis B virus (HBV) globally. This includes 350 million

chronic carriers of the virus. The infection is supposed to be causally related to 1 to 2 million

deaths per year worldwide .In India, too, hepatitis B is a major public health problem. India


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comes under the intermediate zone (2 to 7%) of HBV prevalence, the carrier rate being

approximately 5%.

Globally:

50 million new cases every year

350-400 million chronic carriers(75% in asia)

5,20000 death per year.

United states:

1. 1,40,000 to 3,20,000 new cases per year

2. 1.25 million chronic carriers(0.3% of adult population)

3. 4-5000 deaths per year.

ADVANTAGES OF RECOMBINANT VACCINE

No chance of host becoming ill from the agent, since it is just a

single protein.

It doesnot need an adjuvant.an adjuvant is an agent that stimulates

the immune system to find and react to the vaccine agent.some

adjuvants have been implicated in causing cancers in animals

overtime.

DISADVANTAGES OF RECOMBINANT VACCINE

Isolated proteins may have a different three dimensional structure

than the protein in its normal context,and will induce antiobodies

that may not recognise the organism.

Subunit vaccines often elicit weaker antibody responses than the

other classes of vaccine.

ant vaccines wrf hepatitis b final

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