Lactic acid bacteria - promising vaccine vectors: possibilities, limitations, doubts

Abstract

SummaryGram-positive, nonpathogenic lactic acid bacteria (LAB) are considered to be promising candidates for the development of novel, safe production and delivery systems of heterologous proteins. Recombinant LAB strains were shown to elicit specific systemic and mucosal immune responses against selected antigens. For this reason, this group of bacteria is considered as a potential replacement of classical, often pathogenic, attenuated microbial carriers. Mucosal administration of recombinant LAB, especially via the best explored and universal oral route, offers many advantages in comparison to systemic inoculation, and is attractive from the immunological and practical point of view. Research aimed at designing efficient, mucosally applied vaccines in combination with improved immunization efficiency, monitoring of in vivo antigen production, determination of optimal dose for vaccination, strain selection and characterization is a priority in modern vaccinology. This paper summarizes and organizes the available knowledge on the application of LAB as live oral vaccine vectors. It constitutes a valuable source of general information for researchers interested in mucosal vaccine development and constructing LAB strains with vaccine potential.

Oral recombinant Lactobacillus vaccine targeting the intestinal microfold cells and dendritic cells for delivering the core neutralizing epitope of porcine epidemic diarrhea virus

“…Induction of mucosal immunity should be focused on the interaction between the antigen and lymphocytes within the mucosa. One promising approach involves the use of live recombinant Lactobacillus which can colonize the gastrointestinal tract and compete with pathogens for mucosal binding sites [10]. Cell wall associated or secreted factors from some Lactobacillus strains can enhance innate immune responses and epithelial barrier function, modulate the intestinal micro-environment, regulate immune cell behavior, and elicit release of cytokines [11].…”

Rotavirus vaccine efficacy: current status and areas for improvement

“…Also, different strains have distinct adjuvant and adhesive abilities, can persist in the gut for varying amounts of time and can lead to the expression of diverse cytokines. 83 Examples include oral and intranasal delivery of SARS coronavirus spike protein displayed by Lactobacillus casei in mice leading to specific serum IgG as well as intestinal and lung IgA responses with in vitro neutralization activity. 79 Also, Lactococcus lactis expressing HPV16 E7 antigen with or without co-administration of strain expressing IL-12 were used in intranasal immunization of mice.…”

Selected commensal bacteria change profiles of Helicobacter pylori‐induced T cells via dendritic cell modulation

“…Selected LAB strains were shown to prevent Hp colonization due to the synthesis of lactic acid which alters pH and inactivates urease, an enzyme without which the viability of Hp is fairly limited . The LAB participation in the control of Hp infection may include the following: (a) enhancement of APCs’ ability for Hp antigens presentation to T cells, (b) modification of cytokines expression profile by immune cells, and (c) determination of T‐cell differentiation patterns . However, the LAB immunomodulatory activities strongly depend both on the strains used and the experimental systems applied for the studies .…”