Related Experiment Video
Updated: Jan 28, 2026

In Vitro ELISA Test to Evaluate Rabies Vaccine Potency
Published on: May 11, 2020
Differences in Antigenic Structure of Inactivated Polio Vaccines Made From Sabin Live-Attenuated and Wild-Type
Laura Crawt1, Eleanor Atkinson2, Alison Tedcastle1
1Division of Virology, National Institute for Biological Standards and Control, Herts, United Kingdom.
Background:
Following the declaration of wild-type 2 poliovirus eradication in 2015, the type 2 component was removed from the live-attenuated oral polio vaccine (OPV). This change implies a need to improve global coverage through routine immunization with inactivated polio vaccine (IPV), to ensure type 2 immunity. Several manufacturers use Sabin OPV strains for IPV production (sIPV), rather than the usual wild-type strains used for conventional IPV (cIPV). However, in contrast to cIPV, potency assays for sIPV have not been standardized, no international references exist, and no antigen units have been defined for a sIPV human dose. Thus, sIPV products from different manufacturers cannot be compared, and the relationship between antigenicity and immunogenicity of sIPV is not well understood.
Methods:
A collaborative study was conducted in which laboratories used different methods to measure the antigen content of a set of sIPV and cIPV samples with an aim to identify a suitable reference for sIPV products.
Results:
The study revealed differences in the reactivity of antibody reagents to cIPV and sIPV products.
Conclusions:
Homologous references are required to measure the antigen content of IPV products consistently. The first World Health Organization international standard for sIPV was established, with new, specific Sabin D-antigen units assigned.
Related Concept Videos
Vaccinations
Cancer Vaccines
Cancer vaccines come in two categories: preventive (prophylactic) and treatment (active). Preventive vaccines, such as the Human Papillomavirus (HPV) vaccine, protect against viruses that cause certain...
Types of Impact
The coefficient of restitution is a metric for understanding the dynamics of impacts. It quantifies the ratio of relative velocity...
X-Inactivation
Transcription Attenuation in Prokaryotes
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
Types of Non-structural Cracks in Concrete
Plastic shrinkage cracks typically form within hours after the concrete is poured. The concrete's surface dries faster than the bottom, creating tensile stress that the still-plastic concrete cannot withstand, leading to diagonal or randomly patterned cracks on the concrete surface.

