vaccines-gynecologic-oncology-2018-posters

Page 102

Journal of Clinical Immunology and Allergy

ISSN: 2471-304X

E u r o p e a n C o n g r e s s o n

Vaccines & Vaccination

and Gynecologic Oncology

Vaccines & Vaccination and Gynecologic Oncology 2018

O c t o b e r 2 6 - 2 7 , 2 0 1 8

B u d a p e s t , H u n g a r y

etanus toxoid is one of the most successful vaccines used in immunization programme almost all over the world. Neonatal

tetanus can be prevented by immunizing women of childbearing age with tetanus toxoid, either during pregnancy or outside of

pregnancy. Tetanus vaccine is used either in mono or in combination with other antigens i.e. Diphtheria, Pertussis (whole cell or a

cellular), Hepatitis B, Haemophilus influenza B, Inactivated polio vaccine etc. Tetanus toxoid is produced batch-wise using complex

media, often containing poorly defined components. Therefore, batch related quality control to guarantee safety and potency is a

statutory requirement. In the new concept, quality control is seen as an instrument to monitor consistency of the critical steps in

the production process and testing of vaccines. Monitoring consistency places emphasis on in-vitro methods, since in-vivo tests

are less appropriates (expensive, time consuming and inaccurate) for this purpose. Immunochemical techniques may include

the use of polyclonal antibodies for direct ELISA or monoclonal antibodies in capture ELISA and immunoblotting to indicate local

differences in antigenicity. There is no uniformity in the potency test of tetanus toxoid. Potency assays in animals may be seen

as a way of estimating relative antigen contents parallel to the in-vitro estimations; e.g. by the flocculation tests or the Mancini

test. In animal tests, however, it is the ability to provoke production of antibodies (immunogenicity) that is utilized and not just

the ability to react with antibodies (antigenicity). This distinction might be carried even further. In challenge tests, the ability to

create protection against toxin challenge is the reaction used (protective immunogenicity). In antibody production assays the

ability to provoke production of antibodies reacting in a certain antibody detection system is used. In the past, the potency of

tetanus toxoid was being expressed in Lf - units. United States Pharmacopoeia prescribed antibody induction method. British

Pharmacopoeia, other European countries and World Health Organization recommended active challenge method for assaying

the potency of tetanus component. However, Indian Pharmacopoeia prescribed both the methods viz. antibody titration method

and active challenge method. For the potency estimation of tetanus toxoid component in mono-valent or combination vaccines,

the challenge test has been in use for many years. Despite the use of large number of animals (> 100 mice or guinea pigs) to

test one batch of tetanus toxoid, this test has not been shown to correlate with immunogenicity in humans. However, toxin-

neutralizing antibodies induced by the vaccine are generally accepted as correlates of protection. The three 'R’s concept for the

replacement, reduction and refinement of the use of laboratory animal testing is now widely accepted as not only need for ethical

but also for scientific reasons.

This study on immunogenicity of tetanus toxoid is focused on the following parameters to analyse and evaluate the quality of

toxoid:

• Comparative study of active challenge method and direct ELISA method for assaying the immunogenicity.

• Comparative study of active challenge method and capture ELISA method for assaying the immunogenicity.

• Comparative study on potency by active challenge method and antibody induction method.

Immunological studies on tetanus toxoid

Rakesh Kumar

Serum Institute of India Limited, India

Journal of Clinical Immunology and Allergy, Volume: 4

DOI: 10.21767/2471-304X-C2-006

Euro Vaccines 2018