CRITICAL FACTORS IN DETERMINING THE ANTIGENIC COMPOSITIONOF A VACCINE

A. Its capacity to induce a protective response:-direct antibodies against externalAntigen-direct both B and T cell responseT cell important for intracellularparasites

B. Strain variations:

Single vs. multiple antigens – Flu would be multiple antigens, And changes with time

2. OTHER FACTORS TO CONSIDER WHEN GIVINGVACCINATIONS:

A. ROUTE-oral, intramuscular, intravenousEx. Salk vaccine – inactive, intra-Muscular. Confers protection to Brain, spinal cord, does not pro-Tect the intestines against polio Virus and does not therefore Prevent dissemination of virus.

Sabin vaccine – live attenuated,Oral – protects intestines as well As brain and spinal cord, and doesPrevent dissemination of virus

B. TIMING:-in advance of potential exposure autumn for flu prior to schooling for early childhood diseases

C. CONDITION OF THEPATIENT-age, genetic makeup, infection,-Pregnancy, immunosuppressive-StateEx. – if pregnant, no live agents

D. POTENTIAL RISKS-probability of exposureEx. – health care workers andHepatitis B, postal workers andanthrax

ACTIVE VS. PASSIVE VACCINATION

1. LIVE UNATTENUATED

• MEANS LIVE, BUT NOT WEAKENED

• CLOSELY RESEMBLES ACTUAL INFECTIONPROBLEM WITH FINDINGSUCH AN ORGANISM

EXAMPLES – HOGCHOLERA, SMALLPOX

+ AND -

2. LIVE ATTENUATED

• MEANS LIVE BUT WEAKENED

• ATTENUATED THROUGH COLD-ADAPTATION, BY GROWING IN UNNATURAL HOST

EXAMPLES:MEASLES, MUMPS,RUBELLA, POLIO (SABIN), TUBERCULOSIS

+ AND -

3. INACTIVATED

• A POLITE WORD FOR DEAD

• USING HEAT, FORMALDEHYDE, METHANOL, RADIATION

EXAMPLES:CHOLERA, PERTUSSIS, PLAGUE, INFLUENZA,POLIO (SALK)

+ AND -

Which of the three vaccinesNeeds to be the mostConcentrated? Why?Live unattenuatedLive attenuatedInactivated

Which of the three vaccinesWould require booster(s)?Why?Live unattenuatedLive attenuatedInactivated

4. TOXOIDS

• PREPARED TO PROTECT AGAINST

BACTERIAL EXOTOXINS

PREPARED BY HEATING IN FORMALINPRECIPITATING WITHALUMALUM SERVES AS ANADJUVANT

EXAMPLES:DIPHTHERIATETANUS

+ AND -

5. SUBUNIT

• MADE FROM A PIECE OR PART OF THE WHOLE

• THROUGH BIOCHEMICAL PURIFICATION OR GENETIC ENGINEERING

EXAMPLES:INFLUENZA, HEPATITIS B, H. INFLUENZAEPNEUMOCOCCUSMENINGOCOCCUS

+ AND -

**GLYCOSOLATION

6. INFECTIOUS AGENTS AS CARRIERS OF GENES FOR

ANTIGEN PRODUCTION• GENES CODING FOR THE DESIRED

EPITOPE ARE INSERTED INTO A BENIGN CARRIER – A VIRUS, BACTERIA OR YEAST

EXAMPLES:HEPATITIS BMALARIA

+ AND -

7. SYNTHETIC VACCINES

• PRODUCING SYNTHETIC POLYPEPTIDE VACCINES

• THROUGH GENETIC ENGINEERING

• IDENTIFY AMINO ACID SEQUENCE

• OFTEN PAIR PEPTIDES WITH LIPID

• THIS ELICITS A STRONGER IMMUNE REPSONSE

EXAMPLES:S. PYOGENESDIPHTHERIA ,H. INFLUENZAE IN CUBA

+ AND -