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PubMed1988

Amino-terminal nucleotide-binding sequences of a Lactobacillus deoxynucleoside kinase complex isolated by novel affinity chromatography.

A highly efficient new affinity medium for deoxycytidine kinase, deoxycytidine 5'-tetraphosphate-Sepharose (dCp4-Sepharose), has been constructed. A dCp4-Sepharose column effects a one-step, 19,000-fold, purification to homogeneity of dCyd kinase from the ammonium sulfate fraction of Lactobacillus acidophilus R-26 extract, with 60% recovery. dCTP, a potent end-product inhibitor, is used as an eluent, and it also stabilizes the extremely labile purified enzyme. A noncompeting deoxyadenosine kinase activity accompanies the deoxycytidine kinase activity eluted. Native polyacrylamide gel electrophoresis shows a single protein band, which coincides with both deoxycytidine kinase and deoxyadenosine kinase activities at several gel concentrations. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals a single polypeptide band of 26,000 daltons. Since the native enzyme is known to have an Mr of 50,000, it appears that the enzyme is composed of two subunits of similar size. Sequence analysis of the intact protein from the N-terminus reveals but a single amino acid species per residue up to the 17th residue; at the 18th, 21st, 26th, and 27th residue positions of the sequence, however, there appear to be two different amino acids in almost equal amounts. This may indicate that the enzyme is composed of two nonidentical subunits having the same amino acid sequence near the N-terminus. Residues 6-13 contain the highly conserved Gly-X-X-Gly-X-Gly-Lys sequence found at the active sites of kinases and other nucleotide-binding proteins.

Amino Acid Sequence↗
PubMed2004

Viability of lactic acid bacteria and bifidobacteria in fermented soymilk after drying, subsequent rehydration and storage.

To develop a probiotic dietary adjunct, soymilk fermented with various combinations of lactic acid bacteria (Streptococcus thermophilus and Lactobacillus acidophilus) and bifidobacteria (Bifidobacterium longum and Bifidobacterium infantis) was subjected to freeze-drying and spray-drying. Survival of the starter organisms during the drying process, subsequent rehydration at different temperatures and during a 4-month period of storage under different storage conditions was examined. After freeze-drying, lactic acid bacteria and bifidobacteria exhibited a survival percent of 46.2-75.1% and 43.2-51.9%, respectively, higher than that noted after spray-drying. Regardless of the drying condition, S. thermophilus showed a higher percentage of survival than L. acidophilus, while B. longum survived better than B. infantis. Further study with soymilk fermented with S. thermophilus and B. longum revealed that the freeze-dried and spray-dried fermented soymilk rehydrated at 35-50 degrees C and 20 degrees C, respectively, was optimum for the recovery of the starter organisms. Both S. thermophilus and B. longum survived better in the freeze-dried than the spray-dried fermented soymilk during storage. A higher percent of survival was also noted for both the starter organisms when the dried fermented soymilk was stored at 4 degrees C than 25 degrees C. Holding the dried fermented soymilk in the laminated pouch enabled S. thermophilus and B. longum to exhibit a higher percentage of survival than in the deoxidant- and desiccant-containing glass or polyester (PET) bottle. Among all the packaging materials and storage temperatures tested, starter organisms were most stable in the dried fermented soymilk held in laminated pouch and stored at 4 degrees C. Under this storage condition, S. thermophilus and B. longum showed a survival percentage of 51.1% and 68.8%, respectively, in the freeze-dried fermented soymilk after 4 months of storage. Meanwhile, S. thermophilus and B. infantis in the spray-dried fermented soymilk showed a survival percent of 29.5% and 57.7%, respectively.

Beverages↗
PubMed2006

Antioxidative activities of soymilk fermented with lactic acid bacteria and bifidobacteria.

To further the goal of developing a probiotic dietary adjunct using soymilk, soymilk is fermented with lactic acid bacteria (Lactobacillus acidophilus CCRC 14079 or Streptococcus thermophilus CCRC 14085) and bifidobacteria (Bifidobacterium infantis CCRC 14633 or Bifidobacterium longum B6) individually, and in conjunction. We investigate several antioxidative activities including the inhibition of ascorbate autoxidation, the scavenging effect of superoxide anion radicals and hydrogen peroxide, and the reducing activity exerted by different varieties of fermented soymilks. In addition, the effect of spray-drying and freeze-drying on changes in antioxidative activity is examined. We find that in fermented soymilk both the inhibition of ascorbate autoxidation, and the reducing activity and scavenging effect of superoxide anion radicals varied with the starters used, but nevertheless are significantly higher than those found in unfermented soymilk. In general, antioxidative activity in soymilk fermented with lactic acid bacteria and bifidobacteria simultaneously is significantly higher (P < 0.05) than that fermented with either individually. Moreover, antioxidative activity increases as the fermentation period is extended. However, unfermented soymilk shows an H2O2-scavenging effect, while there is no scavenging effect except for the accumulation of H2O2 in fermented soymilk. Finally, we find that freeze-drying causes a significantly lesser (P < 0.05) reduction in the antioxidative activity of soymilk than does spray-drying. Irrespective of the drying method and the starters used for fermentation. The antioxidative activity of fermented soymilk reduces after drying yet remains higher than that of dried unfermented soymilk.

Antioxidants↗
PubMed2004

In vitro growth, acidogenicity and cariogenicity of predominant human root caries flora.

Streptococcus mutans (Sm), Lactobacillus acidophilus (La) and Actinomyces israelii (Ai) have been associated with root surface caries, which is an increasing problem in elderly Chinese. The aim of this study therefore, was to evaluate in vitro, the growth, acidogenicity and cariogenicity of these organisms, both in mono- and co-cultures using an in vitro model. Forty-eight root specimens were prepared using intact extracted human molars. Fresh, wild-type bacteria obtained from root caries lesions were assembled into seven experimental groups as either mono- or co-cultures and incubated with the root specimens. Appropriate controls were included. Growth curve of each experimental group was monitored for 24h, aerobically, at 37 degrees C using a microplate reader. The pH of the medium was recorded after 24-h incubation using a pH meter. Mean depths of artificial root lesions produced in each cultural group were measured using polarized light microscopy in specimens cut into thin sections (100+/-20 microm). Compared with mono-cultures, synergistic growth was observed in co-cultures of 'La+Sm', 'Ai+La' and 'Ai+La+Sm'. Mean lesion depth produced in La group was significantly shallower than other mono- or co-culture groups (p<0.01). The pH values of all culture media were similar after 24-h incubation. The current data elucidate the complex interactions of three predominant bacterial species considered prime agents of human root surface caries.

Acids↗
PubMed2003

CbsT2 from Lactobacillus johnsonii 100-100 is a transport protein of the major facilitator superfamily that facilitates bile acid antiport.

We previously identified two conjugated bile acid transporters, CbsT1 and CbsT2, in Lactobacillus johnsonii 100-100 and Lactobacillus acidophilus KS-13 that are gene duplicates encoded in tandem with a conjugated bile salt hydrolase (BSH) [Elkins and Savage, J. Bacteriol. 180:4344-4349, 1998; Elkins et al., Microbiology 147: 3403-3412, 2001]. CbsT2 from 100-100 was shown to increase taurocholic acid (TCA) uptake in Escherichia coli; however, higher levels were achieved when an extracellular factor (EF) from 100-100 was present in the assay medium (spent medium from 100-100, pH 4.2). We continued this study here to determine the role of EF in this transport system. Kinetic studies revealed that the previously observed CbsT2- and EF-mediated TCA accumulation is rapid (< 15 s) but not saturable, suggesting that EF is limiting. In addition, uptake of TCA by E. coli expressing CbsT2 was insensitive to ionophores, 2,4-dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone, and thus, is independent of the proton motive force. Since BSH converts [24-(14)C]TCA to [24-(14)C]cholic acid (CA), we measured net radiolabel uptake in E. coli cells expressing transporter(s) and BSH. Interestingly, such cells accumulated less 14C radiolabel (by approximately half) than cells expressing CbsT2 alone. These data can be explained if CA diffuses out of E. coli through the transporter(s). We, therefore, added exogenous, unlabeled CA to EF-spent media, which under our assay conditions, performed similarly to EF+ culture supernatant in TCA and CA uptake assays. Thus, unlabeled CA (a protonated, neutral lipophile) can partition directly into E. coli cells especially at low pH. These findings were validated in uptake assays with [3H]TCA, which yields [3H]taurine (a hydrophilic moiety) upon hydrolysis by the BSH. Amounts of cell-associated 3H radiolabel remained similar in cells expressing CbsT2 and BSH versus cells expressing only CbsT2, both of which were higher than in cells expressing BSH alone. Our data support a hypothesis that these transporters, which comprise a new subfamily of the major facilitator superfamily, facilitate antiport of TCA and CA.

Amino Acid Sequence↗
PubMed2002

A mixed-bacteria ecological approach to understanding the role of the oral bacteria in dental caries causation: an alternative to Streptococcus mutans and the specific-plaque hypothesis.

For more than 100 years, investigators have tried to identify the bacteria responsible for dental caries formation and to determine whether their role is one of specificity. Frequent association of Lactobacillus acidophilus and Streptococcus mutans with caries activity gave credence to their being specific cariogens. However, dental caries occurrence in their absence, and the presence of other bacteria able to produce substantial amounts of acid from fermentable carbohydrate, provided arguments for non-specificity. In the 1940s, Stephan found that the mixed bacteria in dental plaque produced a rapid drop in pH following a sugar rinse and a slow pH return toward baseline. This response became a cornerstone of plaque and mixed-bacterial involvement in dental caries causation when Stephan showed that the pH decrease was inversely and clearly related to caries activity. Detailed examination of the pH (acid-base) metabolisms of oral pure cultures, dental plaque, and salivary sediment identified the main bacteria and metabolic processes responsible for the pH metabolism of dental plaque. It was discovered that this metabolism in different individuals, in plaque in different dentition locations within individuals, and in individuals of different levels of caries activity could be described in terms of a relatively small number of acid-base metabolic processes. This led to an overall bacterial metabolic vector concept for dental plaque, and helped unravel the bacterial involvement in the degradation of the carbohydrate and nitrogenous substrates that produce the acids and alkali that affect the pH and favor and inhibit dental caries production, respectively. A central role of oral arginolytic and non-arginolytic acidogens in the production of the Stephan pH curve was discovered. The non-arginolytics could produce only the pH fall part of this curve, whereas the arginolytics could produce both the fall and the rise. The net result of the latter was a less acidic Stephan pH curve. Both kinds of bacteria are numerous in dental plaque. By varying their ratios, we were easily able to produce Stephan pH curves indicative of different levels of caries activity. This and substantial related metabolic and microbial data indicated that it is the proportions and numbers of acid-base-producing bacteria that are at the core of dental caries activity. The elimination of S. mutans, as with a vaccine, was considered to have little chance of success in preventing dental caries in humans, since, in most cases, this would simply make more room for one or more of the many acidogens remaining. An understanding of mixed-bacterial metabolism, knowledge of how to manipulate and work with mixed bacteria, and the use of a bacterial metabolic vector approach as described in this article have led to (1) a more ecological focus for dealing with dental caries, and (2) new means of developing and evaluating anti-caries agents directed toward microbial mixtures that counter excess acid accumulation and tooth demineralization.

Animals↗
PubMed2005

Antimicrobial activity and tightness of a DCPD-CaO-based hydraulic calcium phosphate cement for root canal filling.

Calcium hydroxide is currently used in dentistry for endodontic treatments where its main advantage is its antibacterial and anti-inflammatory activity. However, it also has some drawbacks such as pulp necrosis, slight solubility, slow and insufficient hardening, and retraction on drying. In consequence, it is used only as temporary material for root canal disinfection. By mixing calcium hydrogen phosphate dihydrate (CaHPO4 . 2H2O, also called dicalcium phosphate dihydrate, DCPD) and calcium oxide with a sodium phosphate buffer as liquid phase, we obtained a CPC with better mechanical properties than calcium hydroxide pastes. The setting reaction produced either hydroxyapatite (HA) or a mixture of HA and calcium hydroxide depending on the relative masses of DCPD and CaO in the cement powder. The presence of calcium hydroxide a priori confers antimicrobial properties to this cement which were investigated in agar plates (diffusion method) against Streptococcus mutans, Lactobacillus acidophilus, Candida albicans, Enterococcus faecalis, Staphylococcus hominis (clinical isolates), and a preparation of polymicrobial flora isolated from dental plaque. The cement samples tested were prepared at molar calcium-to-phosphate ratios (Ca/P) of 1.67 to 2.75. A pure calcium hydroxide paste was used as reference material. Clear and reproducible bacterial growth inhibition was observed for cement samples with Ca/P > or = 2 against all the microorganisms tested. With Ca/P = 2.5, this cement alkalinizes dentinal tubules and provides a fluid-tight sealing that well compares with sealing obtained using a zinc oxide-eugenol cement without gutta-percha point. DCPD-CaO-based cement is therefore a potential root canal filler.

Anti-Bacterial Agents↗
PubMed2006

In vitro evaluation of the antibacterial activity of Arctium lappa as a phytotherapeutic agent used in intracanal dressings.

The discovery of natural biocomponents from plants with antibacterial activity on endodontic microbiota may lead to new therapies. This study evaluated the antibacterial activity of a phytotherapeutic agent prepared from an ethyl acetate fraction (AcOEt) extracted from Arctium lappa. This agent was compared with calcium hydroxide as an intracanal dressing. Twenty-seven maxillary canines were instrumented, sterilized and inoculated with a mixed bacterial suspension of Pseudomonas aeruginosa, Escherichia coli, Lactobacillus acidophilus, Streptococcus mutans and Candida albicans. The teeth were divided into three groups and their canals filled with: group 1, calcium hydroxide and propylene glycol; group 2, a paste containing AcOEt fraction of A. lappa and propylene glycol; group 3, propylene glycol (control). At 7, 14 and 30 days, three teeth from each group were opened and a paper point was placed in the root canal for 5 min. The paper points were transferred to Petri dishes with Brain Heart Infusion (BHI). The bacterial growth was classified. Mild bacterial growth was found in group 1 at all time intervals; in group 2 there was severe growth at 7 days, but no growth at 14 and 30 days. The phytotherapeutic agent extracted from an AcOEt fraction of A. lappa inhibited the growth of all the microorganisms in this study.

Acetates↗
PubMed2001

Identification of predominant human and animal anaerobic intestinal bacterial species by terminal restriction fragment patterns (TRFPs): a rapid, PCR-based method.

Identification of predominant human and animal intestinal tract anaerobes by conventional methods is cumbersome, time-consuming and less sensitive as compared to molecular methods. We have developed a molecular technique to identify most of the abundant intestinal microflora by polyermase chain reaction (PCR) amplification of a 16S rRNA gene fragment using a pair of universal PCR primers. The forward PCR primer was labelled with 6-carboxyfluorescein amino hexy (6-FAM) fluorescent dye to detect the terminal fragment of the PCR products after digestion with restriction enzymes. The PCR products were purified and digested with restriction enzymes and were analysed by capillary electrophoresis using an automated DNA sequencer. The data was analysed with GeneScan software 2.1. Eleven bacteria (Eubacterium biforme, E. limosum, Peptostreptococcus productus, Lactobacillus acidophilus, Bacteroides thetaiotaomicron, B. vulgatus, B. distasonis, Clostridium clostridiiforme, C. leptum, C. perfringens and Escherichia coli) that are predominant in human and animal intestinal tract were successfully identified by this rapid molecular technique. This protocol is rapid, accurate, sensitive and capable of identifying multiple organisms in a single sample.

Animals↗
PubMed2002

Development of a membrane-array method for the detection of human intestinal bacteria in fecal samples.

A membrane-array method was developed for the detection of human intestinal bacteria in fecal samples without using the expensive microarray-arrayer and laser-scanner. The 16S rDNA sequences of 20 predominant human intestinal bacterial species were used to design oligonucleotide probes. Three 40-mer oligonucleotides specific for each bacterial species (total 60 probes) were synthesized and applied to nitrocellulose membranes. Digoxigenin (DIG)-labeled 16S rDNAs were amplified by polymerase chain reaction (PCR) from human fecal samples or pure cultured bacteria using two universal primers, and were hybridized to the membrane-array. Hybridization signals were read by NBT/BCIP color development. The 20 intestinal bacterial species tested were Bacteroides thetaiotaomicron, B. vulgatus, B. fragilis, B. distasonis, Clostridium clostridiiforme, C. leptum, Fusobacterium prausnitzii, Peptostreptococcus productus, Ruminococcus obeum, R. bromii, R. callidus, R. albus, Bifidobacterium longum, B. adolescentis, B. infantis, Eubacterium biforme, E. aerofaciens, Lactobacillus acidophilus,Escherichia coli, and Enterococcus faecium. The two universal primers were able to amplify full size 16S rDNA from all of the 20 bacterial species tested. The hybridization results indicated that the membrane-array method is a reliable technique for the detection of predominant human intestinal bacteria in the fecal samples. The result was also confirmed by using specific PCR methods for these bacteria.

Adult↗
PubMed1996

Levels of antinutritional factors in pearl millet as affected by processing treatments and various types of fermentation.

Pearl millet (Pennisetum typhoideum) was fermented with Lactobacilli or yeasts alone and in combination, and with natural microflora after various processing treatments, as grinding, soaking, debranning, dry heat treatment, autoclaving and germination. Fermentation was carried out at 30 degrees C for 48 hours with Lactobacillus plantarum (LP) and Rhodotorula (R) isolated from naturally fermented pearl millet and Lactobacillus acidophilus (LA), Candida utilis (CU) and natural microflora (NF). Germination and autoclaving, and debranning and autoclaving were the most effective processing treatments to reduce the phytic acid, amylase inhibitors and polyphenols. There was a further reduction in these antinutrients due to fermentation. Phytic acid and amylase inhibitors were completely eliminated after fermentation in some of the samples especially in soaked, debranned and germinated ones. Polyphenols were altered non-significantly in general but fermentation with Lp + R and NF caused a significant increase in polyphenols.

Fermentation↗
PubMed1993

Partial characterization of an rpoD-like gene of Lactococcus lactis subsp. lactis ML3 with a polymerase chain reaction-based approach.

With degenerated oligonucleotide primers for conserved regions of bacterial sigma factor proteins, a 117-bp internal DNA fragment of an rpoD-like gene of Lactococcus lactis subsp. lactis ML3 was amplified by the polymerase chain reaction (PCR). The DNA sequence of this PCR product was determined by cycle sequencing, and the deduced amino acid sequence of this internal fragment showed an extensive homology with the known sigma factor sequences from six other microorganisms and present a 13-amino acid region corresponding to the typical "RpoD box" of primary sigma factors. This PCR product was used as a probe to specifically detect sigma homologs in Pediococcus acidilactici, Leuconostoc lactis, Lactobacillus helveticus, Lactobacillus acidophilus, Enterococcus faecalis, Streptococcus thermophilus, and Lactococcus lactis subsp. cremoris. These data are consistent with the existence of a high similarity between the primary sigma factors from diverse Gram-positive microorganisms.

Amino Acid Sequence↗
PubMedDate not supplied

The intestinal microflora and its colon cancer connection.

Epidemiologic studies suggest that the incidence of colon cancer is influenced by environmental factors, especially diet. The high beef-high fat-low fiber diet of Western societies is associated with a high risk of colon cancer. The intestinal microflora may play a role in colon cancer by metabolic activation of procarcinogens in the lumen of the large bowel. The link between diet and colon cancer can be explained, in part, by the alterations in fecal bacterial enzyme activity induced by a Western-style diet. For example, fecal bacterial beta-glucuronidase, nitroreductase, azoreductase and steroid 7-alpha-dehydroxylase activities are increased in animals or humans consuming a high beef diet. These enzyme activities can be reduced by eating a grain diet, by the addition of Lactobacillus acidophilus to the diet, or by administration of low dose antibiotics. In experimental animals these three measures to reduce the activity of the microflora also produce few colon tumors in animals given the chemical carcinogen dimethylhydrazine. Further studies are needed to establish whether alterations in the metabolism of the colonic microflora can reduce the risk of large bowel cancer in humans.

Bacteria↗
PubMed1994

Biotherapeutic role of fermented milk.

Fermented milk was used as therapy in infantile diarrhoea due to post-gastroenteritis syndrome. This treatment eliminated the disease in 4.0 days (mean value, SD = 2.8; n = 13) and allowed patients to return to free feeding according to their age. The weight percentile variation during treatment with fermented milk (15 days) was higher in the patients showing 3rd degree malnutrition than in other children. Bacteriotherapy can restore faecal flora which has been lowered by diarrhoea. Our results showed that levels higher than 10(6) UFC lactobacilli/g of faeces correlated with a healthy status of the children. Clinical applications of fermented milk with a mixture of Lactobacillus casei and Lactobacillus acidophilus in the prevention of gastrointestinal disorders are possible.

Animals↗
PubMed2002

Adhesive property of Bifidobacterium lactis LKM512 and predominant bacteria of intestinal microflora to human intestinal mucin.

The adhesive property to the intestinal mucin of Bifidobacterium lactis LKM512, B. longum, B. breve, B. bifidum, B. adolescentis, B. infantis, Bacteroides vulgatus, Bacteroides distasonis, Eubacterium aerofaciens, Clostridium perfringens, Escherichia coli, and Lactobacillus acidophilus were examined. Adhesive rate of LKM512 to the mucin was significantly (p < 0.05, 0.01, or 0.001) stronger than the other strains from 2 to 100 time. Though the adhesive property of many strains was almost same to the mucin of 20-year-old and 50-year-old generations, in case of 4-month-old was different. Adhesive inhibitory effect of C. perfringens to the mucin by LKM512 was examined. Under the condition that LKM512 was 108/ml and that C. perfringens was 106/ml, adhesion of C. perfringens to the mucin was inhibited at 99.6%, when LKM512 adhered in advance. There was the strong inhibition of adhesion at 74.0%, when C. perfringens adhered to mucin in advance. Thus, LKM512 can inhibit the adhesion of harmful bacteria to the intestinal mucin, the possibility of using as a probiotic strain has to be verified.

Adult↗
PubMed2000

pS86, a new theta-replicating plasmid from Enterococcus faecalis.

The complete nucleotide sequence of the small (5149 bp) and cryptic plasmid pS86 from Enterococcus faecalis ssp. faecalis S-86 has been determined. Sequence analysis revealed six putative open reading frames (ORFs) encoding polypeptides of 28.3, 11.5, 8.4, 65.1, 7.3, and 11.96 kDa each. Based on sequence similarity, two cassettes have been identified in pS86: ORF1 codes for the replication initiation protein (Rep); ORF4 codes for a putative mobilization protein that shows similarities to Mob/Pre proteins from plasmids of Gram-positive bacteria. No function could be assigned to the other putative ORFs found. According to our results, pS86 plasmid could use a theta-mode of replication, similar to the recently described theta-type replicons from pUCL287 (Tetragenococcus halophila) and pLA1 or pLA105 (Lactobacillus acidophilus) plasmids.

Bacterial Proteins↗
PubMed2001

The replicon of the cryptic Plasmid pSBO1 isolated from Streptococcus bovis JB1.

The cryptic plasmid pSBO1 (3904 bp) was isolated from Streptococcus bovis JB1. pSBO1 contained an open reading frame (ORF) that is homologous to sequences encoding the replication protein (Rep) in pEFC1 (isolated from Enterococcus faecalis), pSK639 (Staphylococcus epidermidis), pLA103 (Lactobacillus acidophilus), and pUCL287 (Tetragenococcus halophila). In addition, four 22-bp direct repeats (DRs) were located upstream of the putative replication gene (rep) of pSBO1. Recombinant plasmids (pSBE10 and pSBE11) containing the DRs and putative rep of pSBO1 replicated in S. bovis 12-U-1 and no8 strains. This result indicates that the putative rep encoded Rep and that the replicon of pSBO1 contained the DRs and the rep. Gel shift assays showed that the Rep of pSBO1 bound the 22-bp DRs.

Amino Acid Sequence↗
PubMed2002

Specific IgA response, T-cell subtype and cytokine profile in experimental intravaginal trichomoniasis.

Trichomoniasis caused by Trichomonas vaginalis may lead to either a complete absence of symptoms or to severe inflammatory manifestations in infected women. Studies of the role of immune responses in the pathogenesis and varied symptomatology of this disease are lacking. Mice may prove useful as an experimental model for intravaginal trichomoniasis in developing an understanding of the role of local immune responses in the pathogenesis and varied symptomatology of this disease. The present study reports the levels of anti-Trichomonas IgA antibodies in serum and vaginal washes, and T-cell subtype and cytokine profile in vaginal cervical tissues of mice infected intravaginally with T. vaginalis isolates from 15 symptomatic and 15 asymptomatic women. It also correlates the responses with symptomatology of the patients. Successful intravaginal infection was established by inoculating T. vaginalis in BALB/c mice preinoculated with Lactobacillus acidophilus and pretreated with oestradiol. A significant increase in specific IgA antibody levels was detected with enzyme-linked immunosorbent assay in vaginal secretions and serum samples collected on the 7th post-infection day from animals infected with isolates from asymptomatic women when compared with mice infected with isolates from symptomatic women. T-cell subset analysis showed significant differences, with increased CD4+ T-cell count in animals infected with isolates from asymptomatic women compared with animals infected using isolates from symptomatic women. No difference in CD8+ T cells was observed between the two groups. Cytokine profile revealed significantly higher (P < 0.001) production of gamma-IFN and IL-2 in mice infected with asymptomatic isolates compared with animals infected with symptomatic isolates, using T. vaginalis crude antigen extract and nonspecific mitogen (ConA) as stimulants for vaginal cervical lymphocytes. However, no difference in IL-4 levels was observed in the two groups of animals. In contrast, significant increase in tumour necrosis factor (TNF-alpha) levels was observed in animals infected with asymptomatic isolates compared with those infected with isolates from symptomatic women and controls, thereby indicating that TNF-alpha may play an important role in the inflammatory response to trichomoniasis. The study further suggests that specific IgA antibodies might help to protect asymptomatic individuals from severe infection and T-lymphocytes may play an important function in the eradication of the parasite. The cytokine profile indicated the involvement of Th-1 like responses in mice infected with asymptomatic isolates, compared with those infected with symptomatic isolates.

Animals↗