As the Covid-19 pandemic continues with myriad variants, current vaccine technology is struggling to keep up. Often employing B-cell immune responses, vaccines are unable to “anticipate virus mutations”, rendering the patient “vulnerable to infection”. According to Alexandre Le Vert, CEO and Co-founder of Osivax, newer T-cell based approaches can combine with current technology to tackle the “internal, less variable, parts of viruses”. The result would be protection against immediate and future strains.
Le Vert, in the European Pharmaceutical Review, explains how SARS and influenza typically target respiratory cells to cause inflammation. The haemagglutinin and spike surface antigens are susceptible to “spontaneous mutation”, thus presenting several shapes and splitting themselves into variants or strains. Most vaccines attack these surface antigens, but “lack the capacity to produce cross-reactive responses” to neutralise multiple strains.
Suggesting that targeting the “more conserved regions of the virus”, Le Vert identifies that these are “less prone to mutations”. They can only be detected by the “T-cell component of the immune system”. He suggests that “several” biotechs have recognised this and are exploring vaccine solutions. Nanoparticles and mRNA vaccines have been developed to present several regions of the haemagglutinin and are known to “provide better cross-protection”.
Another “disruptive approach”, which companies like Osivax and Imutex are exploring, comprises vaccines targeting the “heart” of a virus. This uses the T-cell approach. Osivax’s technology platform, oligoDOM, elicits a T-cell response that targets a virus’ internal antigens. So far it appears that the platform can trigger a universal response capable of multiple variants of a virus.
This technique, deployed against influenza, demonstrated “cross-protection against all A and B strains tested”. Furthermore, in a Phase IIa trial, OVX836 displayed an “excellent safety profile”. The trial also proved strong “activation of the cellular component of the immune system”. Further trials are planned to establish the benefits of co-administration with a standard QIV.
Looking forward, Le Vert predicts that “broad-spectrum vaccines” could offer “robust protection” against future viruses that mutate regularly. He reflects that Covid-19 highlighted a need for “improved approaches” but also “showcased” the progress that can be achieved through collaborative innovation.
To hear Alexandre Le Vert discussing T-cell vaccine updates at the World Vaccine Congress in Europe, 2022, follow this link!
