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G Perdigon

Publications and source records attributed to G Perdigon.

17 recordsLinked to original sources
PubMed2006

Study of cytokines involved in the prevention of a murine experimental breast cancer by kefir.

Previous studies have shown that compounds released during milk fermentation by Lactobacillus helveticus are implicated in the antitumour effect of this product. Here the effects of the consumption, during 2 or 7 days, of kefir or kefir cell-free fraction (KF) on the systemic and local immune responses in mammary glands and tumours using a murine hormone-dependent breast cancer model were studied. In the tumour control group, mice did not receive these products. At the end of the feeding period, mice were injected subcutaneously with tumour cells in the mammary gland. Four days post-injection, they received kefir or KF on a cyclical basis. Rate of tumour development, cytokines in serum; mammary gland tissue, and tumour isolated cells were monitored. Two-day cyclical administration of both products delayed tumour growth. Both kefir and KF increased IL-10 in serum and decreased IL-6(+) cells (cytokine involved in oestrogen synthesis) in mammary glands. Two-day cyclical administration of KF increased IL-10(+) cells in mammary glands and in tumours and decreased IL-6(+) cells in tumour. This study demonstrated the modulatory capacity of KF on the immune response in mammary glands and tumours and the importance of the administration period to obtain this effect.

Animals↗
PubMed2002

Immunomodulating effects of peptidic fractions issued from milk fermented with Lactobacillus helveticus.

The effect of peptides released during the fermentation of milk on the humoral immune system and on fibrosarcoma growth was studied. Lactobacillus helveticus was able to release peptidic compounds during milk fermentation due to its high proteolytic activity, as was shown by the degree of proteolysis and size-exclusion HPLC elution profiles. Three fractions of these compounds were separated and fed to mice during different periods (2, 5, and 7 d). The humoral immune response was assessed by following the number of IgA-secreting cells, and the antitumor activity was monitored by studying the regression of subcutaneously implanted fibrosarcomas. Feeding during 2 and 7 d with the medium-sized fraction (Fraction II) significantly increased the IgA-producing cells in the intestines, whereas feeding with the large compound fraction (Fraction I) during 5 d and the small compound fraction (Fraction III) during all three feeding periods provided similar increases. A double dose of Fraction II showed the highest IgA-producing cell count. The increase by Fraction III was shown to be caused by the presence of L-Tryptophan. Fraction II significantly decreased the size of fibrosarcoma when previously fed during 7 d, and feeding with Fraction I during 5 d decreased significantly its size after 35 d of growth. Although the mechanisms by which lactic acid bacteria enhance the immune system are not clear, this study clearly shows that bioactive compounds released in fermented milks contribute to the immunoenhancing and antitumor properties of these products. The release of bioactive peptides by lactic acid bacteria can have important implications on the modulation of the cellular immune response.

Adjuvants, Immunologic↗
PubMed2001

Immunomodulating effects of milks fermented by Lactobacillus helveticus and its non-proteolytic variant.

The effect of milks fermented by Lactobacillus helveticus and its non-proteolytic variant on mucosal and tumoral immunity was studied. Milks fermented by Lb. helveticus wild type or its non-proteolytic variant were administered orally to mice for different periods (3, 5 and 7 d). The immune response was assessed by analysing the activity of the peritoneal macrophages, the number of cells secreting IgA associated with the gut-associated lymphoid tissue and with the bronchial-associated lymphoid tissue. The number of cells was determined by direct immunofluorescence. The antitumour activity was monitored by studying the regression of the subcutaneously implanted fibrosarcomas. After 3 d feeding of milk fermented by Lb. helveticus wild type, the number of sIgA increased significantly at both the intestinal and bronchial levels, indicating that a cellular migration had occurred. This effect was not noticeable when milk fermented by Lb. helveticus Protease (-) was orally administered. Both fermented milks (wild type or its variant) exhibited an effect on the activity of the peritoneal macrophages, which might be indirectly correlated to the regression of the fibrosarcoma. Although the mechanism by which the lactic acid bacteria enhance the immune system is not clear, this study clearly suggests that the bioactive compounds released during milk fermentation might contribute to the immunoenhancing properties of these products. By releasing biopeptide, lactic acid bacteria have important implications in modulation of the host's immune response, more specifically its cellular immune response.

Adjuvants, Immunologic↗
PubMed2001

Effect of Lactobacillus casei and yogurt administration on prevention of Pseudomonas aeruginosa infection in young mice.

Pseudomonas aeruginosa is an opportunistic pathogen that rarely causes pulmonary disease in normal hosts but one that is an important cause of acute pneumonia in immunocompromised patients, including neonates, and of chronic pneumonia in patients with cystic fibrosis. The aim of this work was to study the effect of oral administration of Lactobacillus casei and yogurt on prevention of P. aeruginosa lung infection in young mice (3 weeks old). This study demonstrates that oral administration of L. casei or yogurt to young mice enhanced lung clearance of P. aeruginosa and phagocytic activity of alveolar macrophages through a dose-dependent effect. There were, however, no significant differences in white blood cell (WBC) differential counts. Furthermore, it was observed that previous administration of L. casei or yogurt induced a significant increase in IgA and IgM levels in bronchoalveolar lavages (BALs) after a P. aeruginosa infection, although there was no relationship with the serum values.

Administration, Oral↗
PubMed2000

Effect of Lactobacillus reuteri on the prevention of hypercholesterolemia in mice.

Administration of Lactobacillus reuteri CRL 1098 (10(4) cells/d) to mice for 7 d before inducing hypercholesterolemia (by feeding mice with a fat-enriched diet for the subsequent 7 d) was evaluated. At this low dose, L. reuteri was effective in preventing hypercholesterolemia in mice, producing a 17% increase in the ratio of high-density lipoprotein to low-density lipoprotein. Total cholesterol and triglycerides decreased by 22 and 33%, respectively, in the group that was not fed the lactobacilli. The hypocholesterolemic effect produced by L. reuteri CRL 1098 might be considered as indirect evidence of the permanency of the lactobacilli in the gut.

Animals↗
PubMed2000

Gut mucosa morphology and microflora changes in malnourished mice after renutrition with milk and administration of Lactobacillus casei.

Nutrition plays a key role in maintaining the balance of the intestinal microflora. Malnutrition disturbs the ecological barrier and induces histological damage. We evaluated modifications induced by renutrition with nonfat milk (NFM) and Lactobacillus casei administration (for 2 days) on the bacterial gut population and structural and ultrastructural gut modifications in malnourished mice. Balb/c mice suffering from a malnutrition process immediately after weaning (for 21 days) were divided into four groups and were given NFM for 0, 7, 14, and 21 days. Another group was treated in a similar way, but after different periods of NFM administration, mice in this group received L. casei for two consecutive days. All experimental animals were sacrificed by cervical dislocation, and both the microflora and the histological structure of the intestine were studied. In malnourished animals, a decrease in the numbers of Lactobacillus and anaerobic microorganisms was observed, whereas there was an increase in the number of Enterobacteriaceae. In animals treated with NFM and NFM plus L. casei, we could observe an important improvement in the microflora in the small and large intestines but no differences between both treatments. Structural and ultrastructural studies showed a slight improvement 7 days after treatment with NFM, and for 14 and 21 days after renutrition, the mice showed normal intestinal villi, whereas the additional feeding with L. casei for two consecutive days, after different periods of renutrition, yielded an earlier improvement (7 days).

Animals↗
PubMed1998

Evidence for hypocholesterolemic effect of Lactobacillus reuteri in hypercholesterolemic mice.

Swiss Albino mice were fed a diet enriched with fat to produce hypercholesterolemia. The further administration of Lactobacillus reuteri CRL 1098 (10(4) cells/d) to hypercholesterolemic mice for 7 d decreased total cholesterol by 38%, producing serum cholesterol concentrations similar to that of the control group (67.4 mg/ml). This low dose of L. reuteri caused a 40% reduction in triglycerides and a 20% increase in the ratio of high density lipoprotein to low density lipoprotein without bacterial translocation of the native microflora into the spleen and liver. These data suggest that L. reuteri CRL 1098 is an effective hypocholesterolemic adjuvant at a low cell concentration for mice.

Animals↗
PubMed1996

Chemical composition of the cell wall of lactic acid bacteria and related species.

In order to examine the relationship between biological activities and the cell wall content, the murein type and the teichoic acid of the cell wall from five strains of bacteria were studied. Two of these Lactobacillus casei CRL 431 and L. acidophilus CRL 730, are used in a commercial fermented milk (BIO MILK), which is believed to be beneficial for health. The other strains, Lactococcus lactis CRL 526, Pediococcus pentosaceus CRL 923 and Propionibacterium acidipropionici CRL 1198 were included in order to compare the cell wall structures of active and inactive strains. A method was designed to confirm the amino acids of the peptidoglycan in impure substrates. Four of the studied strains, L. casei, L. acidophilus, L. lactis and P. acidipropionici, contained glycerol teichoic acids. L. casei, L. acidophilus, P. pentosaceus and L. lactis contained A4 alpha type murein, while P. acidipropionici contained A3 gamma type. The capacity of orally administered peptidoglycans of the studied strains to stimulate phagocytosis by mouse peritoneal macrophages was analyzed. Only the PG of L. casei showed this activity. No differences were observed between active and inactive strains with respect to the chemical composition of the peptidoglycan. Therefore the biological activity is unlikely to be due to the peptidoglycan structure.

Animals↗
PubMed1995

Immune system stimulation by probiotics.

The immune system consists of organs and several cell types. Antigen interaction with these cells induces a cellular immune response mediated by activated cells and a humoral immune response mediated by antibodies. The cellular interactions are enhanced by adhesion molecules, and the activated cells release different cytokines. These complex cellular interactions induce a systemic immune response. If the antigen penetrates by the oral route, a secretory immune response is obtained, which is mediated by secretory IgA. The determination of the number of T or B cells, the quantitative or qualitative measure of the cytokines, antibody levels, or the study of cellular function such as phagocytic activity is used to evaluate the state of the immune system. The effects of lactic acid bacteria on the systemic immune response and on the secretory immune system are described. Potential health benefits of lactic acid bacteria include protection against enteric infections, use as an oral adjuvant, the immunopotentiator in malnutrition, and the prevention of chemically induced tumors. The results showed that Lactobacillus casei could prevent enteric infections and stimulate secretory IgA in malnourished animals, but could produce bacteria translocation. Yogurt could inhibit the growth of intestinal carcinoma through increased activity of IgA, T cells, and macrophages.

Animals↗
PubMed1990

Comparative activation states of tumor-associated and peritoneal macrophages from mice bearing an induced fibrosarcoma.

Balb/c mice bearing a methylcholanthrene-induced fibrosarcoma were used to compare the activation levels of tumor-associated and peritoneal macrophages. Two stages of tumor growth were examined, namely "small" and "large" tumors, with average diameters of 10 and 30 mm, respectively. The activation state, determined by measurement of both phagocytic index and beta-glucuronidase content, was found to be markedly higher in tumor-associated macrophages than in their peritoneal counterparts and it was, in addition, independent of tumor progression. The percentage of tumor-associated macrophages, which were detected on the basis of Fc receptor expression, remained constant in the growing neoplasm, at approximately 23% of total cell population. None of these parameters were affected by inoculation with an immunopotentiating dose of heat-killed Candida albicans which, on the other hand, seemed not to alter the course of the tumor. These data suggest that within the tumor microenvironment macrophages would somehow be maintained at a constant proportion and at a highly activated state, while outside the tumor they would be at a lower activation level. Our results also suggest that TAM would not possess antitumor activity in vivo, although we have found this activity in vitro.

Animals↗
PubMed1990

Prevention of gastrointestinal infection using immunobiological methods with milk fermented with Lactobacillus casei and Lactobacillus acidophilus.

The protective effect of feeding milk fermented with a mixture of Lactobacillus casei sp. and Lb. acidophilus sp. against Salmonella typhimurium infection in mice was compared with that obtained feeding milks fermented with these microorganisms individually. The survival rate obtained after oral infection with Sal. typhimurium was 100% in mice pretreated by feeding during 8 d with the mixture of Lb. casei and Lb. acidophilus fermented milks. Similar treatments with the individual milks were ineffective. Moreover, mice became more susceptible to infection with Sal. typhimurium after such treatment. The colonization of liver and spleen with the pathogen was markedly inhibited by the pretreatment with the mixture of fermented milk, while such inhibition was not observed using the Lb. casei and Lb. acidophilus milks. The highest levels of anti-salmonellae antibodies in serum and in intestinal fluid were found in the group of mice fed with the mixture and with Lb. casei fermented milk respectively. However, this latter milk was not effective in protecting against Sal. typhimurium. When the mice were first infected with Sal. typhimurium and then fed with the mixture of fermented milks, pathogen colonization was not prevented. The results suggest that the augmentation of resistance to salmonellae caused by the treatment with Lb. casei- + Lb. acidophilus-fermented milk was due to the anti-salmonellae protective immunity mainly mediated by the mucosal tissue. Milk fermented with this mixture could be used as an immunobiological method to prevent gastrointestinal infection.

Animals↗
PubMed1987

Enhancement of immune response in mice fed with Streptococcus thermophilus and Lactobacillus acidophilus.

Swiss mice, fed for 8 consecutive d with 50 micrograms/d of viable cultures of Lactobacillus acidophilus and Streptococcus thermophilus, showed significant variation in their immune system. In order to study this phenomenon assays for macrophage and lymphocyte function were carried out. Both lactic acid bacteria enhanced significantly the enzymatic and phagocytic activity of peritoneal macrophages as checked against the controls and also accelerated the phagocytic function of the reticuloendothelial system as revealed by the carbon clearance test. On the 2nd d (100 micrograms), L. acidophilus reached a peak of K = .271, which remained high. Streptococcus thermophilus was effective only on the 2nd d and then decreased. The lymphocytic activity studied by immunoglobulin secreting cells was assayed by Jerne's method of plaque-forming cells (PFC). This activity also was increased by the two microorganisms. Streptococcus thermophilus proved more effective than L. acidophilus. Lactobacillus acidophilus and S. thermophilus activated macrophages and lymphocytes and produced the same increase in the immune response of mice whether administered orally or intraperitoneally.

Administration, Oral↗
PubMed1986

IgG precipitating and non-precipitating antibodies in rabbits repeatedly injected with soluble and particulate antigens.

The immune response of precipitating antibodies and non-precipitating antibodies of high affinity (co-precipitating) of the IgG class was analyzed in rabbits repeatedly injected with egg albumin (as a soluble antigen) B. abortus-egg albumin and polymerized egg albumin (as particulate antigens). The results showed that the levels of anti-egg albumin non-precipitating antibodies induced by the soluble antigen were never higher than 10-15% of total antibodies throughout the experimental time. When particulate antigens were injected, the levels of non-precipitating antibodies increased up to 30-70% of the total antibody levels. This phenomenon is related to the way in which the antigen is available to the immune system (particle or aggregated), and is independent of the response induced by the particulate carrier. Components from the cell wall or bacterial membrane that could act as coadjuvants do not participate in this phenomenon. The results obtained seem to indicate that possibly there was a suppression of the synthesis of precipitating antibodies, and this would produce a relative increase in the non-precipitating antibodies.

Agglutination↗
PubMed1986

Effect of perorally administered lactobacilli on macrophage activation in mice.

The effect of perorally (p.o) administered Lactobacillus casei and L. bulgaricus on macrophage activation in mice was studied. L. casei and L. bulgaricus were administered p.o. to mice for 8 days. The macrophage activation was measured on days 2, 3, 5, and 8 of lactobacillus administration by using biochemical and functional criteria. We measured the release of lysosomal hydrolases, the level of a nonlysosomal enzyme, and in vitro phagocytic activity of mouse peritoneal macrophages. All the assays were performed comparatively with mice inoculated with L. casei and L. bulgaricus (viable and nonviable cells) intraperitoneally (i.p.) at the same dose as for p.o. administration. The phagocytic activity was significantly higher in mice treated i.p. than in control mice. For p.o. administration, there was an increase only when L. casei was used. L. bulgaricus had little effect. No differences were found between viable and nonviable cells. The phagocytic function of the reticuloendothelial system was tested by the carbon clearance test, which showed that L. casei and L. bulgaricus accelerate the phagocytic function in mice treated p.o and i.p., from day 2 onward. These observations show that L. casei and L. bulgaricus given by p.o. administration are able to activate macrophages in mice and suggest that these bacteria, when passing through the intestinal tract, may be responsible for the enhanced host immune response. This fact is very significant because the diet includes fermented and manufactured products containing lactobacilli.

Administration, Oral↗
PubMed1986

Significance of the presence of bovine milk beta-glucuronidase in mastitis detection.

The presence of beta-glucuronidase enzyme in bovine milk was related both to the existence of major and minor pathogens and to somatic cell counts. The detection of this enzyme in whole milk was made possible by the use of p-nitrophenyl-beta-glucuronide as a substrate. This detection allowed us to determine abnormal udder secretions with a high degree of specificity and sensitivity. The particular method of enzyme determination was considered important for mastitis detection because beta-D-glucuronidase, the most significant enzyme in inflammatory processes, is released selectively. The relationship between enzyme, presence of pathogens, and somatic cell counts was established in 220 milk samples obtained at random from individual quarters of apparently healthy udders of cows from four local dairy farms (Santiago del Estero and Tucuman, Argentina). Four of these samples were from cows of recent parturition and two from cows with severe clinical mastitis. Only 17% of the milk samples were normal with somatic cell counts 500,000 cells/ml or less. This ratio is the usual one throughout the area, and the remaining 83% showed higher somatic cell counts. Taking the latter as 100%, the presence of beta-glucuronidase and the positive bacteriological analyses represented 76 and 74%, respectively.

Animals↗
PubMedDate not supplied

Influence of the oral administration of lactic acid bacteria on iga producing cells associated to bronchus.

Intestinal, respiratory and genitourinary mucosal surfaces are the most important routes of entry for microbial pathogens. The stimulus of the mucosal immunity is not easy because the trigger keys for the activation do not follow the ones of the systemic immune response. In previous works we have demonstrated that some Lactic Acid Bacteria (LAB), when orally administered, can induce an enhance of the gut immune response. Taking into account the concept of a common mucosal response, we studied the effect of orally administered mice with Lactobacillus casei, L. acidophilus, L. rhamnosus, L. delbrueckii subsp. bulgaricus, Streptococcus salivarius subsp. thermophilus and Lactococcus lactis on the IgA secreting cells associated to bronchus. As shown before, oral immunostimulation with LAB induced an increase of the IgA* cells at intestinal level by a dose depending effect. In this study it is also showed that the LAB assayed, with exception of L. acidophilus, were able to enhance IgA+ cells at bronchial level, being also this effect dose dependent. The increment induced by some LAB in the number of IgA+ cells on the mucosa surface of the lower respiratory tract may be very important to prevent bronchus diseases.

Journal Article↗