•LAB have been successfully used in the last years as safe mucosal delivery vectors.•L. lactis is considered as the model LAB and an excellent vector of medical proteins.•We report on the development ...of a Stress-Inducible Controlled Expression (SICE) system.•We validated SICE system in a model of therapy against IBD.•We validated SICE system in a model of mucosal vaccination against HPV-16.
In recent years, recombinant lactic acid bacteria (LAB) have been successfully used as safe mucosal delivery vectors. Herein, we report on the development of a Stress-Inducible Controlled Expression (SICE) system in L. lactis for the production and delivery of proteins of health interest (both therapeutic and vaccine related) at mucosal surfaces. This system is episomal in nature and is composed of a vector carrying an expression cassette under the transcriptional control of a stress-inducible promoter. The functionality of the SICE system was validated in vivo using two different routes of administration: oral and intranasal, and in two different murine models of human pathologies: (i) a model of therapy against inflammatory bowel diseases (IBD) and (ii) a model of vaccination against human papillomavirus type-16 (HPV-16).
Human papillomavirus (HPV) is the causative agent of cervical cancer (CxCa) and the most commonly sexually transmitted pathogen worldwide. HPV type 16 (HPV-16) E7 oncoprotein is constitutively ...produced in CxCa and considered as a good antigen candidate for the development of new therapeutic CxCa vaccines. Here, we report the use of non-genetically modified, E7-expressing lactic acid bacteria (LAB) by using the cell-binding domain from
Lactobacillus casei
A2 phage lysin as a cell wall anchor. The versatility of this system was validated by investigating E7 stability at the surface of
Lactococcus lactis
and
L. casei
, two major species of LAB. Moreover, we demonstrated the successful use of these LAB displaying E7 antigen as a mucosal live vaccine in mice. Altogether, these results show the feasibility of using non-genetically modified LAB for low-cost mucosal immunotherapy against HPV-related CxCa in humans.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, EMUNI, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK
Twenty two strains collected from different artisanal dairy products and various areas in Algeria were identified at species level and characterised at genetic level using PCR and 16S RNA sequencing. ...The growth kinetics of the strains was studied, and the strains were evaluated for several technological activities. After 16S RNA sequencing, the strains were assigned to Enterococcus faecium (50.0%), Limosilactobacillus fermentum (36.4%), Lactiplantibacillus pentosus (9.1%), and Lactiplantibacillus plantarum (4.5%). Most of the strains exhibited good acidification, proteolytic, autolytic, and antimicrobial activities alongside weak lipolytic, flavouring, texturising, and thickening activities. Of the 22 strains studied, 3 exhibited a coagulation time of 8–10 h and a syneresis rate of no more than 2.30 ± 0.42, 4 strains demonstrated a good lipolytic activity and 6 strains had aromatic, texturising, and thickening activities.
Lactose absorption at the level of the small intestine depends on its hydrolysis by β-galactosidase. The activity of this enzyme, which gets to the peak at the beginning and halflife, decreases ...progressively after weaning. This activity loss (hypolactasie) is a physiological phenomenon observed in 70 to 75% of the world’s population. Hypolactasy is transmited according to an autosomal recessive mode to an incomplete penetrance and is linked to polymorphosis located in the promoter region of the gene coding the lactase. A solution is proposed regarding ingestion of dairy dislactosed products or products with unduly low lactose rates. In this study, two different enzymes were used, a β-galactosidase of Bifidobacterium β-gal Bb source and another β-galactosidase of Kluyveromyces lactis β-gal Kl source with different concentrations on lactose degradation in a preparation based on skimmed milk at 4° C during 18h with a 39 g/l lactose rate. Determining hydrolysis rate in lactose was achieved with an enzymatic method using a Megazyme K-lolac kit. The results demonstrated that β-gal Kl (Maxilat) in a 100 µl/L dose gives an optimal performance as compared to β-gal Bb (Nola fit) in residual lactose concentrations 1.85 g/L and 2.78 g/L respectively. However, in a dose that was superior to 1500 and 2000, the β-gal Bb was significantly more performing than β-gal Kl. To sum up, the enzymatic method used to define the residual lactose rate, the kit KLolac, gives very reliable results with a low threshold (LOD 1.62 mg/L).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract A recombinant strain of Lactococcus lactis displaying a cell-surface anchored fibronectin binding protein A (FnBPA) from Staphylococcus aureus (LL-FnBPA) had been shown to be more efficient ...in delivering plasmid than its wild-type counterpart both in vitro and in vivo , and have the ability to orientate the immune response toward a Th2 profile in a context of a DNA vaccination. The aim of this work was to test whether this LL-FnBPA strain could shape the immune response after mucosal administration in mice. For this, we used a mouse model of human papilloma virus (HPV)-induced cancer and a L. lactis strain displaying at its cell surface both HPV-16-E7 antigen (LL-E7) and FnBPA (LL-E7 + FnBPA). Our results revealed a more efficient systemic Th1 immune response with recombinant LL-E7 + FnBPA. Furthermore, mice vaccinated with LL-E7 + FnBPA were better protected when challenged with HPV-16-induced tumors. Altogether, the results suggest that FnBPA displays adjuvant properties when used in the context of mucosal delivery using L. lactis as a live vector.
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