Immunogenicity of a malaria parasite antigen displayed by Lactococcus lactis in oral immunisations

Abstract

A putative protective protein from Plasmodium falciparum merozoites, MSA2, was expressed in two different ways on the cell surface of the Gram-positive food-grade bacterium, Lactococcus lactis. The first display format exploits an LPXTG-type anchoring motif of the lactococcal proteinase PrtP to covalently anchor MSA2 to the genetically modified producer cells. In a second display format, MSA2 was fused to the peptidoglycan-binding domain (Protein Anchor) of the lactococcal cell wall hydrolase AcmA and was non-covalently rebound to the surface of non-genetically modified, non-living high-binder L. lactis cells, termed Gram-positive enhancer matrix (GEM) particles. The L. lactis recombinants carrying covalently bound MSA2 were used to immunise rabbits through nasal and oral routes. The highest levels of IgG antibodies reacting with near-native MSA2 on merozoites was elicited by oral administration. Intestinal antibodies to MSA2 were produced only after oral immunisation. MSA2-specific T h -cell activation could be demonstrated. Based on these results, the immunogenicity in oral immunisations of MSA2, bound non-covalently to non-genetically modified L. lactis GEM particles, was compared with MSA2 that was bound covalently to genetically modified L. lactis. These two forms elicited similar titres of serum antibodies. The results illustrate the potential of using non-genetically modified L. lactis as a safe vaccine delivery vehicle to elicit systemic antibodies, thereby avoiding the dissemination of recombinant DNA into the environment.

Functionality of Sortase A in Lactococcus lactis

“…In contrast, no fluorescence was observed in cells of the srtA mutant, indicating that the cell wall anchor region of PrtP is a substrate of SrtA. The localized fluorescence at the septum suggests that protein cell wall secretion and anchoring could occur at the site of new peptidoglycan synthesis, which is consistent with results showing similar localization of SrtA (9,36) and studies in other bacteria (10,35). To uncover other possible SrtA substrates, cell wall proteins were prepared from the L. lactis IL1403 WT and srtA mutant by mutanolysin treatment (31) and analyzed by two-dimensional electrophoresis (2-DE) as described previously (19).…”

Targeting mucosal dendritic cells with microbial antigens from probiotic lactic acid bacteria

“…The development of bacteria as live vaccine vehicles has focused primarily on the use of attenuated strains of pathogenic bacteria including Samonella, Bortedella, and Listeria Clostridium tetani TTFC Mouse [83] Coronovirus glycoprotein S Mouse HPV-16 E7 Mouse [100] Salmonella enterica FliC Mouse [101] Streptococcus pneumoniae PsaA and PspA Mouse [102] SARS-CoV spike protein Mouse [103] Lactobacillus helveticus S. pneumoniae PsaA Mouse [104] Lactobacillus plantarum Helicobacter pylori UreB Mouse [105] S. pneumoniae PsaA Mouse [104] Lactococcus lactis C. tetani TTFC Mouse [81] Erysipelothrix rhusiopathiae SpaA Mouse [106] H. pylori UreB Mouse [107] HIV Env Mouse [108] HPV-16 E7 Mouse [97] Plasmodium falciparum MSA2 Rabbit [109] Rotavirus VP7 Mouse [110] S. pneumoniae PsaA Mouse Review Mohamadzadeh, Duong, Hoover & Klaenhammer spp. [75][76][77].…”

RecombinantLactobacillus plantaruminduces immune responses to cancer testis antigen NY-ESO-1 and maturation of dendritic cells

“…Conflicting results are also reported regarding the comparison between intragastric and intranasal routes of administration. 7,8 Regardless of the applied strategy, in most studies mucosal immunization resulted in induction of antigen-specific immunity.…”