Are There Any Probiotic-Based Vaccines Available?
Some people have various immunological reactions to vaccinations. A vaccine’s reduced ability to prevent disease can happen for a variety of factors, with potentially fatal or hazardous results. One aspect linked to vaccine failures is the correlations between the microbiota and immunological response after immunization. Sadly, there is conflicting research demonstrating the value of probiotics in modifying vaccination response (most likely due to the heterogeneity of probiotic strains, dosages, and routes of administration). The use of probiotics as vaccine adjuvants, however, is a different potential field of research.
We shall examine the supporting evidence in this piece.
An individual is protected from disease by a vaccine because it encourages the immune system to produce immunity to that disease. 4-5 million lives from diseases like measles, diphtheria, tetanus, pertussis, influenza, and COVID-19 are currently prevented each year thanks to vaccination.
A vaccination is made up of adjuvants and antigens
- Proteins or carbohydrates produced from the pathogen that an adaptive immune response is intended to combat are the typical components of antigens. With mRNA vaccinations, the antigen is created by the body.
- Adjuvants are chemicals added to vaccinations to boost the humoral and/or cellular response to an antigen that has been administered.
When the right antigen and adjuvant are used together, immune responses can be induced more quickly, powerfully, and persistently. Less antigens may also be required to produce protection. For the next 70 years after its introduction in the 1920s, alum was the only adjuvant that was authorized for use in humans. Five more adjuvants have been added to licensed vaccines since the 1990s, although the molecular mechanisms by which they function are still poorly understood.
Mucosal sites are where most infections enter the body. Due to its simplicity of administration and the common-mucosal immune system, mucosal vaccine delivery is appealing given that the defense of these barrier tissues is mediated by innate and adaptive immune responses.
LAB are potential candidates for mucosal vaccine delivery vectors due to their many benefits.
These benefits include easy, painless delivery through the oral or nasal mucosa, as well as affordability. LAB typically only evoke weak immunological reactions against themselves, instead producing large amounts of systemic and mucosal antibodies in response to the absorption of the produced foreign antigen by the mucosal immune system. Moreover, some orally delivered LAB may be used to generate specific immunity in the respiratory tract as well as the intestinal mucosa. This property may be employed to develop SARS-CoV2 vaccines.
For more than 30 years, the potential of LAB as a mucosal vaccine adjuvant has been known. Streptococcus gordonii, Lactococcus lactis, and several lactobacilli species are frequently used as vaccine vectors.
A graphic from a 2019 analysis shows the probiotic and commensal bacteria that have been shown to have vaccine adjuvant characteristics in both animal and human trials.
There are sadly not many vaccines accessible for use worldwide since the attenuated pathogen could revert to virulence.
New kinds of mucosal vaccine vectors, such as recombinant LAB as next-generation mucosal vaccine vectors, are required as a result of these safety concerns because of their inherent acid and bile resistance, stability at room temperature, and capacity to advantageously modulate mucosal innate and adaptive immune responses.
