Rotavirus Vaccines

Creative Biolabs is a world leader in the field of viral vaccine development. With our extensive experience and advanced platform, we are therefore confident in offering the best vaccine development services for Rotaviruses. We guarantee the finest results for our customers all over the world.

Rotavirus is the most common cause of diarrhoeal disease among infants and young children. It is a genus of double-stranded RNA viruses in the family Reoviridae. Nearly every child in the world is infected with rotavirus at least once by the age of five but adults are rarely affected. Immunity develops with each infection, so subsequent infections are less severe. There are eight species of this virus, referred to as A, B, C, D, E, F, G and H. Rotavirus A, the most common species and causes more than 90% of rotavirus infections in humans.

Pathogenesis of Rotavirus Infection

Viral factors determining the pathogenicity of rotaviruses have been investigated in several animal models (mice, rabbits, and piglets). The protein product of RNA segment 4 (VP4) has been found to be a major determinant of pathogenicity in several systems, but products of other structural genes (VP3, VP7) and of non-structural genes (NSP1, NSP2, NSP4) have also been implicated. The recent discovery of NSP4 as an enterotoxin has provided an explanation of the old observation that rotavirus-infected animals exhibit profuse diarrhoea prior to the detection of histologic lesions. NSP4 produces an increase in intracellular Ca²⁺ concentration, disturbing the cellular electrolyte homeostasis. Recently it was found that a peptide of NSP4, which is active as an enterotoxin, is secreted from infected cells and is able to induce intracellular Ca²⁺ elevation and diarrhoea in mice. It is thought that the secreted protein binds to a (still hypothetical) receptor and thus affects uninfected cells. Antibody to NSP4 has been shown to reduce the severity of diarrhoeal disease in suckling mice.

Fig.1 The Rotavirus replication cycle.

Host Responses to Rotavirus Infection

After neonatal or primary rotavirus infection, a mainly serotype-specific humoral immune response is elicited, providing homotypic immunity, but there is also partial protection developing against subsequent Rotavirus infections by other serotypes. The exact correlates of protection remain to be determined but levels of rotavirus-specific coproantibodies of the IgA subclass seem to correlate best with protection, although not in all cases. Humoral antibodies might be directed towards the type-specifying antigens VP7 and VP4, but also towards the inner capsid protein VP6. There is a Rotavirus-specific cytotoxic T cell response, but its exact role in overcoming the infection or in protection against subsequent infections is not known. Natural infection or appropriate vaccination seems to protect from severe disease in subsequent infections, even if the serotype of the challenging virus differs from that of the previous infections or those contained in a vaccine.

The Development of Rotavirus Vaccines

Researchers have considered that immunization with an animal rotavirus may result in naturally attenuated rotavirus in humans. Attenuated human rotaviruses that have been produced by passage in cell culture have also been used in experimental studies. Furthermore, rotaviruses isolated from asymptomatic infants might be naturally less virulent and can be a good candidate for the development of an oral vaccine. Two live oral vaccines are commercially available and recommended by the WHO for all children worldwide, and routinely used for immunization programs in more than 47 countries today.

Creative Biolabs has been developing alternative approach of live oral vaccines that might work better because of idiosyncrasies in the choice of strains, selection of alternative doses or schedules, and lower costs due to local manufacture.

• Using rotavirus strains derived from newborns;
• Using strains derived from a lamb rotavirus;
• Using a bovine-human reassortant strain;
• Using an attenuated human strain.

Alternative approaches are also being developed in Creative Biolabs, including the possible need to shift to an inactivated or non-replicating parenteral vaccine that might protect independently of the oral route of administration or host factors in the child. Inactivated rotavirus vaccine, virus-like particle vaccine, viral vector vaccine, and subunit particle vaccine also have been considered as promising methods.

Creative Biolabs is pleased to share our cutting-edge technology and extensive expertise in the field of Rotavirus vaccines development and has focused on the viral vaccines for years. We can offer high-quality customized services by adjusting protocols to meet even the most specific requirements. If you are interested in our services, please contact us for more details.

Reference

1. Iturriza G M. (2004). “Rotavirus genotyping: keeping up with an evolving population of human rotaviruses”. Journal of clinical virology, 31(4), 259-265.

All of our products can only be used for research purposes. These vaccine ingredients CANNOT be used directly on humans or animals.