Identification of Lactobacillus proteins with different recognition patterns between immune rabbit sera and nonimmune mice or human sera.

BACKGROUND: The genus Lactobacillus belongs to a large heterogeneous group of low G + C Gram-positive anaerobic bacteria, which are frequently used as probiotics. The health-beneficial effects, in particular the immunomodulation effect, of probiotics depend on the strain and dose used. Strain variations may be related to diversity of the cell surface architecture of bacteria and the ability to express specific antigens or secrete compounds. The use of Lactobacillus as probiotic requires a comprehensive understanding of its effect on host immune system. To evaluate the potential immunoreactive properties of proteins isolated from four Lactobacillus strains: L. johnsonii 142 and L. johnsonii 151, L. rhamnosus LOCK 0900 and L. casei LOCK 0919, the polyclonal sera obtained from mouse and human have been tested as well as with sera from rabbits immunized with whole lactobacilli cells. RESULTS: The reactivity of isolated proteins detected by SDS-PAGE and Western blotting was heterogeneous and varied between different serum samples. The proteins with the highest immunoreactivity were isolated, purified and sequenced, in particular the fractions were identified as phosphoglycerate kinase (L. johnsonii 142), glyceraldehyde 3-phosphate dehydrogenase (L. johnosnii 142, L. rhamnosus LOCK 0900), hypothetic protein JDM1_1307 (L. johnsonii 151) and fructose/tagatose-bisphosphate-aldolase (L. casei LOCK 0919). CONCLUSION: The different prevalence of reactions against tested antigens in rabbit, mouse and human sera may indicate significant differences in immune system and commensal cross-talk in these groups. The identification of immunoreactive lactobacilli proteins opens the possibility to use them as an antigens for development of vaccines.

[Biological properties of Lactobacillus surface proteins]. / Wlasciwosci biologiczne bialek powierzchniowych bakterii z rodzaju Lactobacillus.

Lactobacillus, a genus of Gram-positive bacteria, includes many strains of probiotic microflora. Probiotics, by definition, are living microorganisms that exert beneficial effects on the host organism. The morphology and physiology of the Lactobacillus bacterial genus are described. The structure of the cell wall of Gram-positive bacteria is discussed. The surface S-layer of Lactobacillus composed of proteins (SLP) with low molecular mass is presented. Cell surface proteins participating in the regulation of growth and survival of the intestinal epithelium cells are characterized. The influence of stress factors such as increased temperature, pH, and enzymes of gastric and pancreatic juice on SLP expression is described. The ability of binding of heavy metal ions by S-layer proteins is discussed. The characteristics of these structures, including the ability to adhere to epithelial cells, and the inhibition of invasion of pathogenic microflora of type Shigella, Salmonella, Escherichia coli and Clostridium and their toxins, are presented. 

[Surface proteins of bacteria of the genus Bifidobacterium]. / Bialka powierzchniowe bakterii z rodzaju Bifidobacterium.

Beneficial effects due to the presence of probiotic bacteria of the genus Bifidobacterium in the human intestinal tract are still an interesting object of study. So far activities have been confirmed of bifidobacteria in stimulation of the host immune system, stimulation of tumor cell apoptosis, improvement of bowel motility, alleviation of symptoms of lactose intolerance, cholesterol lowering capacity, prevention and treatment of diarrhea and irritable bowel syndrome, alleviation of allergy or atopic dermatitis, maintenance of homeostasis of the intestine, and stimulation of the development of normal intestinal microflora in infants. A multitude of therapeutic properties encourages researchers to investigate the possibility of using the potential of Bifidobacterium in the prevention and treatment of other conditions such as rheumatoid arthritis and depression. Although it is known that the beneficial effects are due to intestinal mucosal colonization by these bacteria, the cell components responsible for the colonization are still not determined. In addition to the beneficial effects of probiotic administration, there were also negative effects including sepsis. Therefore research has been directed to identify specific components of Bifidobacterium responsible for probiotic effects. Currently researchers are focused on identifying, isolating and evaluating the properties of surface proteins that are probably involved in the adhesion of bacterial cells to the intestinal epithelium, improving colonization. This paper is an overview of current knowledge on Bifidobacterium surface proteins. The ways of transport and anchoring proteins in Gram-positive bacterial cells, the assembly of cell wall, and a description of the genus Bifidobacterium are presented.