Explain the term ‘Immunological products’. Discuss any one vaccine in brief.
Immunological Product:
These are the preparations which are meant for the prevention of diseases, such as vaccines or for treatment of diseases.
Immunological Products:
A. Active immunization:
1. Bacterial vaccine.
2. Viral rickettsial vaccine.
3. Toxoids.
B. Passive immunization:
1. Antitoxins.
2. Antiviral serum.
3. Antibacterial serum.
4. Immune blood derivatives.
(i) Method of preparation of BCG vaccine: It is freeze- dried preparation containing live culture of the bacillus Calmette and Guerin strain of Mycobacterium tuberculosis.
Preparation: The bacilli are grown on a suitable culture media until 1 mg when plated out on a suitable solid culture media shows not less than 20 million colonies. The growth period should not be more than 14 days in any case.
After a suitable growth, they are separated by filtration in the form of a cake. The cake is homogenized in a grinding flask and suspended in a suitable sterile liquid medium designed to preserve the antigenicity and viability of the vaccine. The suspension is transferred into the final sterile containers and freeze-dried. Then containers are sealed so as to prevent contamination or deterioration of the vaccine. The vaccine contains no antimicrobial agent
OR.
(ii) Small pox vaccine is prepared by two methods :
By using eggs:
Hen egg is used
(Which is incubated after 12 days)
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Small cut on the shell
(exposed chorio-allantoic membrane)
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In this membrane, viruses are inoculated
(by seed of known potency )
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Cut was sealed by flap or paraffin wax
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Again incubate for 72 hours
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Using aseptic condition, shell is removed and chorio-allantoic membrane is separated
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Contents are added in normal saline solution at 0° C
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Add 50 % glycerin
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Material is ground to produce homogenized suspension.
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Transfer to suitable sterile container and freeze dried
(iii)General method of preparation of toxoids:
A suitable strain of bacteria is grown on liquid medium. Incubation is carried out under optimum conditions until toxin productions has reached a satisfactory level. Filter the media and the filtrate containing toxins are converted by chemical treatment to toxoid in which toxicity has been reduced, but antigenic effect is maintained.
The conversion of toxin to toxoid is done by the treatment with formaldehyde solution at 370 C. The product obtained is known as formal toxoid (FT).
The formal toxoid obtained may be further purified by:
i. Precipitating with alum (APT)
ii. Flocculating it with the corresponding antitoxin (TAF)
iii. Adsorbing an aluminium hydroxide (PTAH) or hydrate aluminium phosphate (PTAP).