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Screening biosurfactant-producing actinomycetes: Identification of Streptomyces sp. RP1 as a potent species for bioremediation

Ayoib A, Gopinath SCB, Zambry NS, Yahya ARM

J Basic Microbiol, 2024 Apr;64(4):e2300585.
PMID: 38346247 DOI: 10.1002/jobm.202300585

This study aimed to isolate biosurfactant-producing and hydrocarbon-degrading actinomycetes from different soils using glycerol-asparagine and starch-casein media with an antifungal agent. The glycerol-asparagine agar exhibited the highest number of actinomycetes, with a white, low-opacity medium supporting pigment production and high growth. Biosurfactant analyses, such as drop collapse, oil displacement, emulsification, tributyrin agar test, and surface tension measurement, were conducted. Out of 25 positive isolates, seven could utilize both olive oil and black oil for biosurfactant production, and only isolate RP1 could produce biosurfactant when grown in constrained conditions with black oil as the sole carbon source and inducer, demonstrating in situ bioremediation potential. Isolate RP1 from oil-spilled garden soil is Gram-staining-positive with a distinct earthy odor, melanin formation, and white filamentous colonies. It has a molecular size of ~621 bp and 100% sequence similarity to many Streptomyces spp. Morphological, biochemical, and 16 S rRNA analysis confirmed it as Streptomyces sp. RP1, showing positive results in all screenings, including high emulsification activity against kerosene (27.2%) and engine oil (95.8%), oil displacement efficiency against crude oil (7.45 cm), and a significant reduction in surface tension (56.7 dynes/cm). Streptomyces sp. RP1 can utilize citrate as a carbon source, tolerate sodium chloride, resist lysozyme, degrade petroleum hydrocarbons, and produce biosurfactant at 37°C in a 15 mL medium culture, indicating great potential for bioremediation and various downstream industrial applications with optimization.

Matched MeSH terms: Actinomyces/metabolism
Fulltext An In Vitro Study On The Anti-Adherence Properties Of Mouthrinses Containing Chlorhexidene Gluconate And Hexitidine

Fathilah, A.R., Othman, Y., Rahim, Z.H.A.

Ann Dent, 1999;6(1):-.
MyJurnal

Chlorhexidine gluconate and hexitidine have been used in many oral health care products as antiplaque and antigingivitis agents. Based on the clinical observations and the plaque and gingivitis scores, chlorhexidine gluconate has been reported to be a better agent. In this study, the anti-adherence properties of chlorhexidine gluconate and hexitidine on individual bacteria strains isolated from a 3-hour plaque (Streptococcus sanguis, Streptococcus mitis 1 and Actinomyces sp.) and on a whole 6-hour plaque culture were determined and compared. The study showed that chlorhexidine gluconate inhibited almost 100 % the adherence of the individual bacteria strains and 87.7 % the adherence of a whole 6-hour plaque culture to the saliva-coated glass surface. Hexitidine appeared to be more selective in its effect. It was shown to inhibit the adherence of S. sanguis and Actinomyces sp. to saliva-coated glass surface by 86.5 % and 51.4 % respectively. Its effect on the S. mitis 1 strains is comparable to that of a whole 6-hour plaque culture where inhibition to adherence were less than 4 % for both.

Matched MeSH terms: Actinomyces
Polymicrobial biofilm formation by Candida albicans, Actinomyces naeslundii, and Streptococcus mutans is Candida albicans strain and medium dependent

Arzmi MH, Alnuaimi AD, Dashper S, Cirillo N, Reynolds EC, McCullough M

Med Mycol, 2016 Nov 01;54(8):856-64.
PMID: 27354487 DOI: 10.1093/mmy/myw042

Oral biofilms comprise of extracellular polysaccharides and polymicrobial microorganisms. The objective of this study was to determine the effect of polymicrobial interactions of Candida albicans, Actinomyces naeslundii, and Streptococcus mutans on biofilm formation with the hypotheses that biofilm biomass and metabolic activity are both C. albicans strain and growth medium dependent. To study monospecific biofilms, C. albicans, A. naeslundii, and S. mutans were inoculated into artificial saliva medium (ASM) and RPMI-1640 in separate vials, whereas to study polymicrobial biofilm formation, the inoculum containing microorganisms was prepared in the same vial prior inoculation into a 96-well plate followed by 72 hours incubation. Finally, biofilm biomass and metabolic activity were measured using crystal violet and XTT assays, respectively. Our results showed variability of monospecies and polymicrobial biofilm biomass between C. albicans strains and growth medium. Based on cut-offs, out of 32, seven RPMI-grown biofilms had high biofilm biomass (HBB), whereas, in ASM-grown biofilms, 14 out of 32 were HBB. Of the 32 biofilms grown in RPMI-1640, 21 were high metabolic activity (HMA), whereas in ASM, there was no biofilm had HMA. Significant differences were observed between ASM and RPMI-grown biofilms with respect to metabolic activity (P <01). In conclusion, biofilm biomass and metabolic activity were both C. albicans strain and growth medium dependent.

Matched MeSH terms: Actinomyces/growth & development; Actinomyces/metabolism; Actinomyces/physiology*
Fulltext Isolation and rapid identification of streptomonospora, a strictly halophilic filamentous actinomycetes from antarctic soil (Barrientos Island, Antarctic)

Cheah Y.K., Lee, L.H., Radu, S., Wong, M.C.V.L., Andrade, H.M.

ASM Science Journal, 2009;3(2):113-120.
MyJurnal

The genus Streptomonospora is a group of extremely halophilic filamentous actinomycetes that form a distinct branch in the 16S rRNA gene phylogenetic tree adjacent to the genera Nocardiopsis and Thermobifida, family Norcadiopsaceae. To date, genus Streptomonospora only contain two validly described species which are Streptomonospora salina and Streptomonospora alba. During a biodiversity study on halophilic filamentous actinomycetes from 18 co-ordinates in Barrientos Island, Antarctic, numerous actinomycetes strains were isolated. To identify whether these isolates were members of the genus Streptomonospora, a genus specific primer that allow the rapid detection of the genus Streptomonospora by means of PCR amplification was used. Furthermore molecular cloning was performed to make identical and multiple copies of the target gene. In addition, morphological characteristic identification was performed to validate isolates with positive amplification during PCR.

Matched MeSH terms: Actinomyces
The induction of oral tolerance to Actinomyces viscosus in mice

Sosroseno W, Bird PS, Gemmell E, Seymour GJ

Oral Dis, 2006 Jul;12(4):387-94.
PMID: 16792724

To determine whether oral tolerance with the oral bacterium Actinomyces viscosus was inducible in mice.

Matched MeSH terms: Actinomyces viscosus/immunology*
Coaggregation of Candida albicans, Actinomyces naeslundii and Streptococcus mutans is Candida albicans strain dependent

Arzmi MH, Dashper S, Catmull D, Cirillo N, Reynolds EC, McCullough M

FEMS Yeast Res., 2015 Aug;15(5):fov038.
PMID: 26054855 DOI: 10.1093/femsyr/fov038

Microbial interactions are necessarily associated with the development of polymicrobial oral biofilms. The objective of this study was to determine the coaggregation of eight strains of Candida albicans with Actinomyces naeslundii and Streptococcus mutans. In autoaggregation assays, C. albicans strains were grown in RPMI-1640 and artificial saliva medium (ASM) whereas bacteria were grown in heart infusion broth. C. albicans, A. naeslundii and S. mutans were suspended to give 10(6), 10(7) and 10(8) cells mL(-1) respectively, in coaggregation buffer followed by a 1 h incubation. The absorbance difference at 620 nm (ΔAbs) between 0 h and 1 h was recorded. To study coaggregation, the same protocol was used, except combinations of microorganisms were incubated together. The mean ΔAbs% of autoaggregation of the majority of RPMI-1640-grown C. albicans was higher than in ASM grown. Coaggregation of C. albicans with A. naeslundii and/or S. mutans was variable among C. albicans strains. Scanning electron microscopy images showed that A. naeslundii and S. mutans coaggregated with C. albicans in dual- and triculture. In conclusion, the coaggregation of C. albicans, A. naeslundii and S. mutans is C. albicans strain dependent.

Matched MeSH terms: Actinomyces/physiology*
Actinomycetic corneal ulcer

Singh M, Kaur B

Eye (Lond), 1989;3 ( Pt 4):460-2.
PMID: 2606221

A rare case of keratoactinomycosis developing in the absence of any known ocular trauma is described. It showed a dramatic response to penicillin therapy. Steroids should be cautiously used in the presence of active corneal disease. This case highlights the importance of repeated examination of corneal scrapings.

Matched MeSH terms: Actinomyces/isolation & purification
Monospecies and polymicrobial biofilms differentially regulate the phenotype of genotype-specific oral cancer cells

Arzmi MH, Cirillo N, Lenzo JC, Catmull DV, O'Brien-Simpson N, Reynolds EC, et al.

Carcinogenesis, 2019 03 12;40(1):184-193.
PMID: 30428016 DOI: 10.1093/carcin/bgy137

Microbial infection has been shown to involve in oral carcinogenesis; however, the underlying mechanisms remain poorly understood. The present study aimed to characterize the growth of oral microorganisms as both monospecies and polymicrobial biofilms and determine the effects of their products on oral keratinocytes. Candida albicans (ALC3), Actinomyces naeslundii (AN) and Streptococcus mutans (SM) biofilms or a combination of these (TRI) were grown in flow-cell system for 24 h. The biofilms were subjected to fluorescent in situ hybridization using species-specific probes and analysed using confocal laser scanning microscopy. The effluent derived from each biofilm was collected and incubated with malignant (H357) and normal (OKF6) oral keratinocytes to assess extracellular matrix adhesion, epithelial-mesenchymal transition (EMT) and cytokines expression. Incubation of OKF6 with ALC3 and TRI effluent significantly decreased adhesion of the oral keratinocyte to collagen I, whereas incubation of H357 with similar effluent increased adhesion of the oral keratinocyte to laminin I, significantly when compared with incubation with artificial saliva containing serum-free medium (NE; P < 0.05). In OKF6, changes in E-cadherin and vimentin expression were not consistent with EMT although there was evidence of a mesenchymal to epithelial transition in malignant oral keratinocytes incubated with AN and SM effluent. A significant increase of pro-inflammatory cytokines expression, particularly interleukin (IL)-6 and IL-8, was observed when H357 was incubated with all biofilm effluents after 2- and 24-h incubation when compared with NE (P < 0.05). In conclusion, C.albicans, A.naeslundii and S.mutans form polymicrobial biofilms which differentially modulate malignant phenotype of oral keratinocytes.

Matched MeSH terms: Actinomyces/physiology
The effect of Piper betle and Psidium guajava extracts on the cell-surface hydrophobicity of selected early settlers of dental plaque

Razak FA, Othman RY, Rahim ZH

J Oral Sci, 2006 Jun;48(2):71-5.
PMID: 16858135

The adhesion of early settlers of dental plaque to the tooth surface has a role in the initiation of the development of dental plaque. The hydrophobic surface properties of the bacteria cell wall are indirectly responsible for the adhesion of the bacteria cell to the acquired pellicle on the tooth surfaces. In this study, the effect of aqueous extract of two plants (Psidium guajava and Piper betle) on the cell-surface hydro-phobicity of early settlers of dental plaque was determined in vitro. Hexadecane, a hydrocarbon was used to represent the hydrophobic surface of the teeth in the oral cavity. It was found that treatment of the early plaque settlers with 1 mg/ml extract of Psidium guajava reduced the cell-surface hydrophobicity of Strep. sanguinis, Strep. mitis and Actinomyces sp. by 54.1%, 49.9% and 40.6%, respectively. Treatment of these bacteria with the same concentration of Piper betle however, showed a comparatively lesser effect (< 10%). It was also observed that the anti-adhesive effect of the two extracts on the binding of the early plaque settlers to hexadecane is concentration dependent.

Matched MeSH terms: Actinomyces/drug effects; Actinomyces/physiology
Actinomycosis of the vocal cord: a case report

Fernandez SH

Malays J Pathol, 1999 Dec;21(2):111-5.
PMID: 11068416

A 30-year-old Chinese lady was admitted for hoarseness of voice of one month's duration. Clinical examination revealed a granuloma of the left vocal cord while chest X-ray showed an opacity in the lower lobe of the right lung. The provisional clinical diagnosis was tuberculous laryngitis. A biopsy of the vocal cord lesion revealed inflamed tissue with actinomycotic colonies. Cultures and sputum smears did not reveal any tuberculous bacilli. The patient responded to a 6-week course of intravenous C-penicillin, regaining her voice on day 5 of commencement of antibiotics. A subsequent CT scan of the neck and thorax revealed multiple non-cavitating nodular lesions in both lung fields, felt to be indicative of resolving actinomycosis. She was discharged well after completion of treatment. It was felt that this is a case of primary actinomycosis of the vocal cord with probably secondary pulmonary actinomycosis.

Matched MeSH terms: Actinomyces/isolation & purification; Actinomyces/pathogenicity*
Anti-plaque effect of a synergistic combination of green tea and Salvadora persica L. against primary colonizers of dental plaque

Abdulbaqi HR, Himratul-Aznita WH, Baharuddin NA

Arch Oral Biol, 2016 Oct;70:117-124.
PMID: 27343694 DOI: 10.1016/j.archoralbio.2016.06.011

OBJECTIVE: Green tea (Gt), leafs of Camellia sinensis var. assamica, is widely consumed as healthy beverage since thousands of years in Asian countries. Chewing sticks (miswak) of Salvadora persica L. (Sp) are traditionally used as natural brush to ensure oral health in developing countries. Both Gt and Sp extracts were reported to have anti-bacterial activity against many dental plaque bacteria. However, their combination has never been tested to have anti-bacterial and anti-adherence effect against primary dental plaque colonizers, playing an initial role in the dental plaque development, which was investigated in this study.
METHODS: Two-fold serial micro-dilution method was used to measure minimal inhibitory concentration (MIC) of aqueous extracts of Gt, Sp and their combinations. Adsorption to hexadecane was used to determine the cell surface hydrophobicity (CSH) of bacterial cells. Glass beads were used to mimic the hard tissue surfaces, and were coated with saliva to develop experimental pellicles for the adhesion of the primary colonizing bacteria.
RESULTS: Gt aqueous extracts exhibited better anti-plaque effect than Sp aqueous extracts. Their combination, equivalent to 1/4 and 1/2 of MIC values of Gt and Sp extracts respectively, showed synergistic anti-plaque properties with fractional inhibitory concentration (FIC) equal to 0.75. This combination was found to significantly reduce CSH (p<0.05) and lower the adherence ability (p<0.003) towards experimental pellicles.
CONCLUSION: Combination between Gt and Sp aqueous extracts exhibited synergistic anti-plaque activity, and could be used as a useful active agent to produce oral health care products.

Matched MeSH terms: Actinomyces viscosus/drug effects*; Actinomyces viscosus/physiology
Fulltext Case report : Actinomyces naeslundii complicating preterm labour in a trisomy-21 pregnancy

Ong HC, Ling AC, Ng DS, Ng RX, Wong PL, Omar SFS

IDCases, 2021;23:e01051.
PMID: 33532241 DOI: 10.1016/j.idcr.2021.e01051

Preterm birth is a global concern with considerable morbidity and mortality. Intrapartum infection is a known cause of preterm birth and Actinomyces infection is one of the infections contributing to preterm birth. We report a case of preterm birth of a trisomy-21 neonate to a mother with positive Actinomyces naeslundii from an intra-operative placental swab sample and discussed the relationship of this bacteria and preterm delivery, and the role of postpartum antibiotics use in this case.

Matched MeSH terms: Actinomyces
Fulltext Predominant supragingival plaque microflora in a Malaysian population

Fathilah, A.R., Rahim, Z.H.A., Othman, Y.

Malaysian Dental Journal, 2007;28(2):92-96.
MyJurnal

The tooth provides a non-shedding surface ideal for microbial and plaque accumulation. Despite being exposed to regular environmental perturbations, the microbial composition and proportions in the plaque often remains in homeostasis and is relatively stable over time. Supragingival plaque sampled from various sites on the tooth surface was pooled and conventionally analyzed for its microbial constituent. Classification of microbial isolates was made based on the characteristics exhibited by the growth colonies, Gram-stained cells, as well as biochemical reactions using the API Identification System kit. Observation was also made of the colony forming units on both non-selective and selective agar culture plates. A variety of bacteria, both of the facultative and anaerobic types, were isolated from the supragingival plaque of the Malaysian population. Among those found to predominate the supragingival plaque include the Gram positive and Gram negative cocci and rods from the genera Streptococcus, Staphylococcus, Actinomyces, Fusobacterium, Corynebacterium, Clostridium, Bacteroides, Veilonella and Lactobacillus. In addition, yeast within the genus Candida was also isolated from the plaque samples.

Matched MeSH terms: Actinomyces
Fulltext A Marine Actinomycete Rescues Caenorhabditis elegans from Pseudomonas aeruginosa Infection through Restitution of Lysozyme 7

Fatin SN, Boon-Khai T, Shu-Chien AC, Khairuddean M, Al-Ashraf Abdullah A

Front Microbiol, 2017;8:2267.
PMID: 29201023 DOI: 10.3389/fmicb.2017.02267

The resistance of Pseudomonas aeruginosa to conventional antimicrobial treatment is a major scourge in healthcare. Therefore, it is crucial that novel potent anti-infectives are discovered. The aim of the present study is to screen marine actinomycetes for chemical entities capable of overcoming P. aeruginosa infection through mechanisms involving anti-virulence or host immunity activities. A total of 18 actinomycetes isolates were sampled from marine sediment of Songsong Island, Kedah, Malaysia. Upon confirming that the methanolic crude extract of these isolates do not display direct bactericidal activities, they were tested for capacity to rescue Caenorhabditis elegans infected with P. aeruginosa strain PA14. A hexane partition of the extract from one isolate, designated as Streptomyces sp. CCB-PSK207, could promote the survival of PA14 infected worms by more than 60%. Partial 16S sequence analysis on this isolate showed identity of 99.79% with Streptomyces sundarbansensis. This partition did not impair feeding behavior of C. elegans worms. Tested on PA14, the partition also did not affect bacterial growth or its ability to colonize host gut. The production of biofilm, protease, and pyocyanin in PA14 were uninterrupted, although there was an increase in elastase production. In lys-7::GFP worms, this partition was shown to induce the expression of lysozyme 7, an important innate immunity defense molecule that was repressed during PA14 infection. GC-MS analysis of the bioactive fraction of Streptomyces sp. CCB-PSK207 revealed the presence of methyl esters of branched saturated fatty acids. In conclusion, this is the first report of a marine actinomycete producing metabolites capable of rescuing C. elegans from PA14 through a lys-7 mediated activity.

Matched MeSH terms: Actinomyces
The role of CD4+ and CD8+ T cells on antibody production by murine Peyer's patch cells following mucosal presentation of Actinomyces viscosus

Sosroseno W, Bird PS, Gemmell E, Seymour GJ

Oral Microbiol. Immunol., 2006 Dec;21(6):411-4.
PMID: 17064401

The aim of this study was to determine the role of CD4 and CD8 cells on specific antibody production by murine Peyer's patch (PP) cells after oral immunization with Actinomyces viscosus in mice. Female DBA/2 mice were orally immunized with three low doses of heat-killed A. viscosus. Sham-immunized mice served as a control group. Mice were depleted of CD4 or CD8 cells by intraperitoneal injection of anti-CD4 or anti-CD8 antibodies daily for 3 days before oral immunization. One week after the last oral immunization, PPs were removed and cell suspensions were cultured with A. viscosus. Specific antibody production in the culture supernatants was assessed by enzyme-linked immunosorbent assay. The results showed that oral immunization with A. viscosus induced a predominant specific immunoglobulin A (IgA) response by PP cells and, to a lesser extent, IgM antibodies. Depletion of CD4 but not CD8 cells suppressed the production of specific antibodies. These results suggest that oral immunization with low doses of A. viscosus may induce the production of specific antibodies by murine PP cells in a CD4-cell-dependent fashion.

Matched MeSH terms: Actinomyces viscosus/immunology*
The effect of immune status, age and genetic background on induction of oral tolerance to Actinomyces viscosus in mice

Sosroseno W, Herminajeng E, Bird P

Biomed Pharmacother, 2015 Mar;70:294-8.
PMID: 25776514 DOI: 10.1016/j.biopha.2014.12.039

The aim of the present study was to determine the effect of immune status, age and genetic background on the induction of oral tolerance to Actinomyces viscosus. Suppression of delayed type hypersensitivity (DTH) response and antigen-specific serum antibody levels could be induced in DBA/2 mice intragastrically and systemically immunized with A. viscocus, suggesting the induction of oral tolerance. In contrast, this immune suppression could be abrogated if the animals had been systemically immunized prior to the induction of oral tolerance with the same bacterium. Long-term systemic immunization prior to intragastric immunization with A. viscocus suppressed DTH response only. Cell transfer of this group of animals also suppressed DTH response in the donors, indicating the action of suppressor cells for inhibition of DTH response. Furthermore, oral tolerance to A. viscocus failed to occur in mice aged at 3 days and 1, 2, 4, 6 and 36 weeks old. Mice bearing H-2(d) haplotype were the most susceptible to oral tolerization, followed by H-2(b) and H-2(k). Therefore, the results of the presence study suggest that the induction of oral tolerance to A. viscosus in mice may be dependence on the immune status and genetic background but not age.

Matched MeSH terms: Actinomyces viscosus*
The anti-adherence effect of Piper betle and Psidium guajava extracts on the adhesion of early settlers in dental plaque to saliva-coated glass surfaces

Razak FA, Rahim ZH

J Oral Sci, 2003 Dec;45(4):201-6.
PMID: 14763515

The aqueous extracts of Piper betle and Psidium guajava were prepared and tested for their anti-adherence effect on the adhesion of early plaque settlers (Strep. mitis, Strep. sanguinis and Actinomyces sp.). The saliva-coated glass surfaces were used to simulate the pellicle-coated enamel surface in the oral cavity. Our results showed that the anti-adherence activities of Piper betle and Psidium guajava extracts towards the bacteria were different between the bacterial species. Psidium guajava was shown to have a slightly greater anti-adherence effect on Strep. sanguinis by 5.5% and Actinomyces sp. by 10% and a significantly higher effect on Strep. mitis (70%) compared to Piper betle. The three bacterial species are known to be highly hydrophobic, and that hydrophobic bonding seemed to be an important factor in their adherence activities. It is therefore suggested that the plant extracts, in expressing their anti-adherence activities, could have altered the hydrophobic nature of the bonding between the bacteria and the saliva-coated glass surfaces.

Matched MeSH terms: Actinomyces/drug effects
Antimicrobial Effect of an Experimental Glass lonomer Cement against Pathogens associated with Deep Carious Lesions

Vamsi K, Siddiqui F

J Contemp Dent Pract, 2018 Jul 01;19(7):824-829.
PMID: 30066686

AIM: To study the antimicrobial effect of chlorhexidine diacetate (CHX-D)-modified type II glass ionomer cement (GIC) against the two predominant deep caries microorganisms, namely Lactobacillus casei and Actinomyces viscosus.
MATERIALS AND METHODS: An experimental GIC (ex-GIC) was prepared by mixing CHX-D powder with the powder of type II GIC to obtain 1% (w/w) concentration of CHX-D in the GIC. Antibacterial activity of this ex-GIC was tested against L. casei and A. viscosus using the agar diffusion method. The ex-GIC specimens were tested in their unset and set forms for each bacterium. For the unset group, specimens were placed in each agar plate immediately after manipulation and for the set group, specimens were placed in each agar plate, 1 hour after manipulation. The inhibition zones on the agar plate were recorded in millimeters immediately on placement of the specimen in the agar plate and after 48 hours. The reading was recorded and statistically analyzed for significant difference.
RESULTS: Mann-Whitney U test showed statistically significant difference in the inhibition zones produced by ex-GIC against L. casei and A. viscosus when both were compared in unset (p-value = 0.002) and set (p-value = 0.031) groups. For both the groups, the zone of inhibition against L. casei was greater. Though the unset group recorded wider zone of inhibition, the difference was not significant when compared with the respective set group. This was true for both the bacterial groups.
CONCLUSION: The 1% CHX-D-modified type II GIC showed antibacterial property against L. casei and A. viscosus and significantly higher activity against L. casei.
CLINICAL SIGNIFICANCE: Addition of 1% CHX-D to type II GIC showed evidence of antibacterial activity against organisms found in deep carious lesion and therefore may exhibit superior antimicrobial efficiency when used as an intermediate therapeutic restoration in deep cavities.

Matched MeSH terms: Actinomyces viscosus/drug effects*
Fulltext Inhibition of attachment of oral bacteria to immortalized human gingival fibroblasts (HGF-1) by tea extracts and tea components

Wang Y, Chung FF, Lee SM, Dykes GA

BMC Res Notes, 2013;6:143.
PMID: 23578062 DOI: 10.1186/1756-0500-6-143

Tea has been suggested to promote oral health by inhibiting bacterial attachment to the oral cavity. Most studies have focused on prevention of bacterial attachment to hard surfaces such as enamel.

Matched MeSH terms: Actinomyces/drug effects
Role of CD4 and CD8 T-cells in the induction of oral tolerance to Actinomyces viscosus in mice

Sosroseno W, Bird PS, Gemmell E, Seymour GJ

Oral Microbiol. Immunol., 2006 Jun;21(3):151-8.
PMID: 16626371

Mucosal presentation of Actinomyces viscosus results in the induction of antigen specific systemic suppressor cells in mice. The aim of the present study was to determine the phenotype of the suppressor cells responsible for the induction of oral tolerance to low doses of A. viscosus. When CD8 cell-depleted DBA/2 mice were intragastrically immunized and systemically immunized with A. viscosus, the delayed type hypersensitivity response was suppressed but not the levels of antigen specific serum antibodies. Adoptive transfer of orally tolerized CD4(+) cells to CD4(+)-depleted mice resulted in suppression of delayed type hypersensitivity response but not of the levels of antigen specific serum antibodies. In contrast, adoptive transfer of orally immunized CD8(+) cells to CD8(+)-depleted mice resulted in partially suppressed delayed type hypersensitivity response but significantly inhibited the levels of antigen specific serum antibodies. When orally tolerized CD8(+) cells were cocultured with systemically immunized CD8(+) cell-depleted spleen cells, splenic specific antibodies were inhibited. However, no suppression of splenic specific antibodies could be observed in the cultures containing orally tolerized CD4(+) cells and systemically immunized CD4(+) cell-depleted spleen cells. The results of the present study suggest that oral tolerance of humoral and cellular immunity induced by low doses of A. viscosus may be mediated by CD8(+) and CD4(+) cells, respectively.

Matched MeSH terms: Actinomyces viscosus/pathogenicity*

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