Safe oral live probiotic vaccines as an alternative to injectables

There are at least 5 million people with chronic obstructive pulmonary disease (COPD) in the Russian Federation. Most exacerbations of COPD are due to a viral infection (influenza and acute respiratory virus infection) with a secondary bacterial infection. In addition, about one third of bacterial lung infections is caused by Streptococcus pneumoniae (pneumococci).

Researchers at the Molecular Basis of Microorganism-Human Interaction Research and Education Centre at the WCRC for Personalized Medicine are working on the development of a complex live probiotic vaccine based on Enterococcus faecium for the prevention of mixed viral-bacterial infections in patients with COPD.

In the course of the research, 3 recombinant strains of Enterococcus faecium have been constructed, into the genome of which fragments of the genes for hemagglutinin, neuraminidase of the influenza A virus and a chimeric DNA fragment from pneumococci encoding the immunogenic surface proteins PsaA, PspA, Spr1875 were cloned. The combination of these recombinant strains is the prototype of a live oral probiotic vaccine against mixed viral-bacterial infections.

In laboratory animal studies, mice vaccinated with a live oral probiotic vaccine candidate were as effectively protected from infection as mice immunized parenterally by injection with the corresponding immunogenic proteins. The protective effect of live vaccines may be synergistic and is associated not only with the induction of specific antibodies against infectious agents, but also with the effect of the probiotic on innate defense mechanisms.

The ease of use and the absence of potentially serious side effects of this fundamentally new type of vaccination for combined protection against viral and bacterial infections make this scientific project extremely promising for national health care.