Evaluation of Adhesion and Viability of Human Gingival Fibroblasts on Strontium-Coated Titanium Surfaces: an in vitro Study.

Background: Applying multifunctional coatings employing strontium (Sr) ions on titanium (Ti) surfaces is a useful and biocompatible method to improve osseointegration and prevent tissue infections through antimicrobial activity. Nonetheless, the effectiveness of Sr coating on the adhesion and viability of human gingival fibroblasts (HGFs) to Ti surfaces remains unclear. Purpose: The study aimed to evaluate the effect of Sr coating on the adhesion and viability of HGFs to Ti surfaces. Materials and Methods: The Ti wafers were divided into two groups based on Sr coating: uncoated Ti (control) and Sr-coated Ti. The Magnetron sputtering technique was used for Sr coating on Ti surfaces. The HGFs were seeded onto the surfaces and cultured for 48 and 96 hours before the cell adhesion and viability of the attached HGFs were assessed. The adhesion of HGFs was analyzed using the attached cell numbers at 48 h and 96 h, and the morphology at 24 h and 72 h. The cytotoxic effect on HGFs was assessed after 24 and 72 hours of incubation using cell viability assay. Student's t-test was used for statistical analysis. Results: The number of cells attached to Sr-coated surfaces was significantly greater than those attached to uncoated Ti surfaces after 48 hours (P<0.0001) and 96 hours (P=0.0002). Sr-coated and uncoated Ti surfaces were not cytotoxic to HGFs, with the cell viability ranging from 92% to 105% of the untreated control HGFs. There were no significant differences in cell viability between Sr-coated and uncoated Ti surfaces at 24 hours (P=0.3675) and 72 hours (P=0.0982). Conclusion: Sr-coated Ti surfaces induce adhesion of HGFs compared to uncoated Ti surfaces. Further, Sr-coated and uncoated Ti surfaces show no cytotoxic effect on the attached HGFs.

Corrigendum to "Anti- E. coli immunoglobulin yolk (IgY): Reduction of pathogen receptors and inflammation factors could be caused by decrease in E. coli load" [Heliyon 9(3) (February 21, 2023) e13876]>.

[This corrects the article DOI: 10.1016/j.heliyon.2023.e13876.].

Anti-E. coli Immunoglobulin Yolk (IgY): Reduction of pathogen receptors and inflammation factors could be caused by decrease in E. coli load.

Graft versus host disease (GVHD) remains the major cause of morbidity and mortality after allogeneic stem cell transplantation, especially for intestinal GVHD, as steroid resistant GVHD results in high mortality. For this reason, new treatments of GVHD are needed. One approach is the reduction of pathogenic bacteria using anti-E. coli Immunoglobulin Yolk (IgY). In a haploidentical murine model, B6D2F1 mice conditioned with total body irradiation (TBI), received bone marrow cells (BM) and splenocytes (SC) from either syngeneic (Syn = B6D2F1) or allogeneic (Allo = C57BL/6) donors. Following this, animals received from day -2 until day +28 chow contained IgY or control chow. Thereafter the incidence and severity of aGVHD, the cytokines, chemokines, IDO1 and different pathogen-recognition receptors (PRR) were analyzed and compared to control animals (received chow without IgY). We found that animals receiving chow with IgY antibody showed reduced GVHD severity compared to control animals. On day28 after alloBMT, IDO, NOD2, TLR2, TLR4 and the inflammatory chemokine CCL3, were reduced in the colon and correlated with a significant decrease in E. coli bacteria. In summary chow containing chicken antibodies (IgY) improved GVHD via decrease in bacterial load of E coli conducting to reduction of pathogen receptors (NOD2, TLR2 and 4), IDO, chemokines and cytokines.

Effects of nanohybrid flowable resin-based composites on fibroblast viability using different light-curing units.

PURPOSE: To investigate the in vitro cytotoxic effects of Bis-GMA-containing and Bis-GMA-free flowable resin-based composites (RBCs) on primary human gingival fibroblast cells (hGFc) using direct and indirect curing methods and three different light-curing units (LCUs). MATERIALS AND METHODS: Cells were isolated and cultured in vitro in 24-well plates. The plates were divided into treatment (cells with RBC), control (cells only), and blank (media only) groups. In the treatment groups, two types of nanohybrid flowable RBCs were used: Bis-GMA-free and Bis-GMA groups. Each treatment group was subdivided according to the curing method, i.e., direct curing (RBC was injected into the wells and cured directly on the attached cells) and indirect curing (the samples were pre-cured outside of the well plate and then added to the well plate with cells). To vary the LCU, the subgroups were further divided into three groups: multiple-emission peak light-emitting diode, single-emission peak light-emitting diode, and quartz-tungsten-halogen units. Curing was conducted for 20 seconds. The hGFc cytotoxicity was evaluated via 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay after 24, 48, and 72 hours of culturing. RESULTS: The MTT assay results showed that both RBCs were significantly cytotoxic toward hGFc compared to the control group (p < 0.0001). The Bis-GMA group was significantly more cytotoxic to the cells compared to the Bis-GMA-free group. In addition, the curing method and time interval affected cell viability regardless of the LCU used. CONCLUSION: The Bis-GMA flowable RBC and direct curing method had the highest cytotoxic effects on hGFc regardless of the LCU used. Careful selection of flowable RBCs and proper curing techniques are required to decrease the cytotoxic effects on hGFc and improve the clinical handling of oral tissues.

The Impact of Nonsurgical Periodontal Therapy on Serum Levels of Dickkopf-Related Protein-1 in Smokers and Nonsmokers with Periodontitis: A Prospective Comparative Study.

Purpose: This study aimed to evaluate and compare Dickkopf-related protein-1 (DKK1) serum levels and periodontal clinical parameters of smokers and nonsmokers with periodontitis at baseline and after nonsurgical periodontal treatment. Patients and Methods: A prospective comparative study was conducted among 24 patients with periodontitis who were divided according to the smoking habits into two groups: nonsmokers (G1) and smokers (G2). All the participants were assessed clinically by recording the probing depth (PD), clinical attachment loss (CAL), plaque index (PI), and bleeding index (BI), and immunologically by measuring the DKK1 serum levels at baseline and six weeks after nonsurgical periodontal therapy. Results: The two groups showed a significant decrease in PI, BI, and CAL after periodontal therapy (p < 0.05), while PD was significantly reduced in G1 (p = 0.005). The PI mean value was significantly higher at the baseline in G2 versus G1 (p = 0.050), while PD, BI, and CAL values were not significantly different between the groups (p = 0.056, p = 0.241, and p = 0.381, respectively). For DKK1 serum levels, there was a statistically significant decrease after treatment compared to the baseline for both groups (G1: p < 0.001; G2: p < 0.001) but no significant difference before (p = 0.131) and six weeks after treatment (p = 0.334) between the two groups. Conclusion: Although nonsurgical periodontal treatment effectively improved periodontal clinical parameters and reduced DKK1 serum levels, there were no significant differences in the DKK1 serum levels among the smokers and nonsmokers with periodontitis.

Evaluation of the cytotoxic effects of a new Harvard MTA compared to MTA Flow and ProRoot MTA on human gingival fibroblasts.

BACKGROUND: Biocompatibility is an essential property for any dental root repair material that may interact with the surrounding periodontal tissues. We hypothesise that the three mineral trioxide aggregate (MTA) restorative brands ProRoot MTA, MTA Flow and Harvard MTA have similar biocompatibility. To test this hypothesis, we compared the cytotoxic effects of these materials on human gingival fibroblast (GF). METHODS: MTA cements were prepared, and after completion of setting, they were incubated in Dulbecco's Modified Eagle Medium for 1 day or 4 days to obtain low and high concentrations of MTA elutes respectively. The elutes of MTA supplemented with fetal bovine serum were added to GF and incubated for 3 days at 37 °C and 5% CO2. Untreated cells were used as control. The cell viability was assessed using a 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay at 24, 48 and 72 h. RESULTS: After 24 h, the MTT assay showed that both 1- and 4-day elutes of MTA flow and Harvard MTA reduced cell viability significantly compared to control (P < 0.05). After 48 h, the 1-day elute of ProRoot MTA induced GF proliferation (P = 0.0136) while MTA flow and Harvard MTA were similar to control. After 72 h, the 1-day elute of ProRoot MTA and Harvard MTA induced GF proliferation, while the elute of MTA flow was comparable to control. The 4-day elute of Harvard MTA continued to be cytotoxic to GF after 24 h, 48 h, and 72 h incubation, while the 4-day elute of ProRoot MTA and MTA flow were similar to control. CONCLUSION: ProRoot MTA and MTA Flow showed comparable biocompatibility. However, the 4-day elute of Harvard MTA was cytotoxic to GF. Further studied are required to assess the cell viability after direct contact with these materials versus eluent in vitro and compare these sealers in the clinical setting.

Effect of root conditioning agents hyaluronic acid, EDTA and chlorhexidine on the attachment of human gingival fibroblasts to healthy root surface.

BACKGROUND: The gold standard treatment of periodontal diseases is scaling and root planing (SRP). Different adjunctive root conditioning agents such as hyaluronic acid (HA), ethylenediaminetetraacetic acid (EDTA), and chlorhexidine (CHX) have been used with SRP to improve the smear layer removal and the healing of periodontal tissues. The aim of this study was to compare the effect of manual scaling with or without HA, EDTA, or CHX root conditioning on the attachment and viability of human gingival fibroblasts (GF). METHODS: Fifteen healthy single rooted teeth were co llected and divided randomly into a scaled (n = 12) and non-scaled control group (n = 3). The scaled roots were subdivided equally into four groups; the first group did not receive any chemical treatment, while the remaining groups were treated with the conditioning agents HA or 17% EDTA or 0.2% CHX gel. Gingival fibroblasts were seeded on the top of each root and incubated for 48 h to allow attachment to the roots. The viability of fibroblasts attached to the root surface was assessed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell viability assay. RESULTS: The cell viability was the highest in the scaled only group (p = 0.0001) while the lowest was in the scaled with EDTA group (p > 0.05). The scaled group was the highest followed by the HA and CHX groups, while the EDTA group showed the lowest mean value. CONCLUSION: SRP remains the superior method for regaining cell attachment to the root surface, leading to better periodontal health, and adjunctive therapies did not enhance the GF attachment to the root surface beyond the effect of SRP. Further studies are needed to investigate the effect of root conditioning agents on periodontally diseased teeth in vitro and compare them in vivo.

Biocompatibility Evaluation of Human and Porcine Acellular Dermal Matrix on Human Primary Gingival Fibroblasts: In Vitro Comparative Study.

OBJECTIVE: Allogeneic and xenogeneic acellular dermal matrix (ADM) grafts have been used to treat periodontal soft tissue defects. The purpose of the current study was to compare the effect of human ADM (AlloDerm) and porcine ADM (Derma) on human primary gingival fibroblasts in vitro regarding the biocompatibility test. MATERIALS AND METHODS: Gingival fibroblasts were obtained from healthy adult gingiva and seeded on AlloDerm or Derma ADM in 96-well plate. The control cells were grown on a surface-treated polystyrene cell-culture plate without matrix. The cells were cultured for 3, 7, and 14 days. The fibroblasts morphology was examined using inverted microscopy, and the cell viability of fibroblasts adherent to the dermal matrix was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay after 3, 7, and 14 days in culture. The data were statistically evaluated by one-way analysis of variance. p-Value of 0.05 was considered significant. RESULTS: Gingival fibroblasts adjacent to the AlloDerm and Derma matrices were healthy, attached to the well, and did not exhibit any cytopathic changes similar to control. There were no statistically significant differences in the cell viability between the gingival fibroblasts attached to Derma and AlloDerm on day 3 (p = 0.841), day 7 (p = 0.198), and day 14 (p = 0.788). CONCLUSION: Considering this in vitro study's limitations, both human and porcine ADM were compatible with the surrounding human primary gingival fibroblasts. No significant differences were observed in the cell viability between the gingival fibroblasts that were attached to Derma and AlloDerm.

Identification of PKHD1 mutations in Brain, Breast and Rectal tumors by Next Generation DNA Sequencing.

INTRODUCTION: It is well established that the PKHD1 mutations are associated with autosomal recessive polycystic kidney disease (ARPKD). Although, PKHD1 mutations are also detected in certain cancer types, to our knowledge in rare tumors such as, atypical teratoid rhabdoid tumor (ATRT), primary neuro-ectodermal tumor (PNET), atypicalchoroid plexus papilloma (a-CPP), amelanotic ano-rectal melanoma (AMM), and breast phyllodes tumors PKHD1 mutations profiling is not reported. METHODS: In order to determine the PKHD1 gene mutation patterns in the brain, rectal, and breast tumors we have analyzed these tumor DNA by Ion Proton Next generation DNA sequencing. RESULTS: Next-generation DNA sequencing on Ion Proton identified unique and common missense mutations in the brain, breast and ano-rectal tumors. All mutations were benign, and only one pathogenic mutation in p. (Cys3346Arg) found in AMM tumor. In phyllodes tumor of breast, two unique missense variants were detected (rs113562492) p. (Met2841Val); and (rs137972270) in p. (Arg589Cys) and these variants are not present in other tumors tested. The variant rs137972270 was reported only in two cases sofar in ClinVar database. Missense variants such as rs115045643, rs116809571, rs115338476, and rs76895755 are found only in PNET, and a variant rs62406032 in a-CPP, another one rs35445653 in ATRT cases were unique for these tumors, which are not present in other tumors. Several synonymous and intronic variants of PKHD1 gene were also found in these tumors. A synonymous variant p. (Asp395Asp), rs1896976 and two intronic SNPs viz., rs1326605, and rs1571084 were found in all tumors tested. The SNP rs9395699 in IVS66 was found uniquely in IPC breast tumor only in this study. Allele coverage, allele ratio, p-value, Phred qual score, sequencing coverage, alleles frequencies were also analysed, the p-values and Phred quality score were significantly higher. CONCLUSION: These tumors did not have any insertion/ deletion mutations, nonsense, or truncated mutations in it. The screening of PKHD1 gene revealed signature mutations for the solid tumors studied by NGS method. This investigation may help in understanding these tumor pathology at molecular level.

Effectiveness of Probiotic Lozenges in Periodontal Management of Chronic Periodontitis Patients: Clinical and Immunological Study.

OBJECTIVE: The main purpose of this article was to evaluate the effect of probiotics used as an adjunctive to scaling and root planing (SRP) on the periodontal parameters and matrix metalloproteinase-8 (MMP-8) levels in gingival crevicular fluid (GCF) of chronic periodontitis patients. MATERIALS AND METHODS: A total of 25 chronic periodontitis patients who completed the treatment course of 40 subjects, aged 25 to 58 years, participated in this study. They were categorized into two groups: the first group was treated by SRP while the second group was treated by SRP and probiotic lozenges twice a day for 30 days. All patients were evaluated clinically by measuring the plaque index, bleeding index (BI), pocket depth, clinical attachment loss, and immunologically by assaying GCF/MMP-8 at baseline and 30 days after periodontal management. RESULTS: There was a significant improvement in periodontal parameters after SRP treatment with and without probiotic lozenges in both groups. However, there was a significant decrease in the BI (p = 0.05) in SRP and probiotic lozenges group after 30 days compared with SRP alone. In addition, there was a significant decrease in GCF/MMP-8 levels after 30 days in patients managed by SRP only (p = 0.017) compared with the baseline in both groups, whereas a highly significant decrease in patients treated by SRP and probiotics (p = 0.001). CONCLUSION: The current study suggested that the probiotics might have a beneficial effect on clinical and immunological outcomes in the management of chronic periodontitis patients. Further research is needed on a large-scale population and for a long recall time to confirm the response to probiotics as an adjunctive to SRP.

Effects of mineral trioxide aggregate, calcium hydroxide, biodentine and Emdogain on osteogenesis, Odontogenesis, angiogenesis and cell viability of dental pulp stem cells.

BACKGROUND: Vital pulp therapy preserves and maintains the integrity and the health of dental pulp tissue that has been injured by trauma, caries or restorative procedures. The enhancement of cells viability and formation of reparative dentine and new blood vessels are vital determinants of the success of direct pulp capping. Therefore, the aims of this study was to evaluate and compare the in vitro osteogenic, odontogenic and angiogenic effects of mineral trioxide aggregate (MTA), calcium hydroxide [Ca(OH)2], Biodentine and Emdogain on dental pulp stem cells (DPSCs) and examine the effects of the tested materials on cell viability. METHODS: DPSCs were treated with MTA, Ca(OH)2, Biodentine or Emdogain. Untreated cells were used as control. The cell viability was measured by MTT assay on day 3. Real-Time PCR with SYBR green was used to quantify the gene expression levels of osteogenic markers (alkaline phosphatase and osteopontin), odontogenic marker (dentin sialophosphoprotein) and angiogenic factor (vascular endothelial growth factor) on day 7 and day 14. RESULTS: All capping materials showed variable cytotoxicity against DPSCs (77% for Emdogain, 53% for MTA, 26% for Biodentine and 16% for Ca(OH)2 compared to control (P value < 0.0001). Osteopontin (OPN) and dentin sialophosphoprotein (DSPP) gene expression was increased by all four materials. However, alkaline phosphatase (ALP) was upregulated by all materials except Emdogain. Vascular endothelial growth factor (VEGF) expression was upregulated by all four tested materials except Ca(OH)2. CONCLUSIONS: Our results suggest MTA, Biodentine and Emdogain exhibit similar attributes and may score better than Ca(OH)2. Emdogain could be a promising alternative to MTA and Biodentine in enhancing pulp repair capacity following dental pulp injury. However, further future research is required to assess the clinical outcomes and compare it with the in vitro findings.

Prevalence of HBV and Assessment of Hepatitis B Vaccine Response among Dental Health Care Workers in Dental Teaching Hospital, Umm Al-Qura University, Saudi Arabia.

Hepatitis-B Virus (HBV) infection is a serious health problem that can be prevented by vaccination. Dental Health Care Workers (DHCWs) are at-risk of occupational exposure to HBV infection. This study was aimed to assess the prevalence of HBV and evaluate the immune response to hepatitis B vaccine among DHCWs in Dental Teaching Hospital, Umm Al-Qura University, Saudi Arabia. A cross-sectional study was conducted on 139 DHCWs, 71 males and 68 females. Blood samples were collected and the levels of hepatitis B surface antigen (HBsAg) and hepatitis B surface antibody (anti-HBs) were measured by Chemiluminescent Microparticle Immunoassay. The prevalence of HBV among DHCWs was zero (0.0%). The hepatitis B vaccine was given to 95% of DHCWs. Among the vaccinated participants, 90.1% (n=119) have protective immunity to hepatitis B. An inverse correlation between anti-HBs levels and increasing the duration of vaccination (P < 0.0001) was found. We compared the anti-HBs levels in 28 students who received childhood vaccine and revaccinated at age of 21. The anti-HBs concentration was greater than 10mIU/mL (protected) in 17.9% of those who had childhood vaccine compared to 100% one-year after revaccination. The mean of anti-HBs levels for childhood vaccine was 5.6 mIU/mL and these levels increased significantly to 620 mIU/mL after recent revaccination (P < 0.0001). In conclusion, Hepatitis B vaccine is effective in prevention of HBV infection among DHCWs. Non-protected individuals should be identified and revaccinated.

Evaluation of chemokine CXCL10 in human gingival crevicular fluid, saliva, and serum as periodontitis biomarker.

PURPOSE: The aim of this study was to evaluate CXCL10 as a biomarker for periodontitis by determining the CXCL10 levels in saliva, serum, and gingival crevicular fluid (GCF) samples from periodontally healthy control subjects and adult subjects with chronic periodontitis. PATIENTS AND METHODS: Adult patients seeking dental treatment at Umm Al-Qura University dental clinic underwent a complete periodontal examination, and saliva, serum, and GCF samples were collected. Subjects were classified as chronic periodontitis patients (n=31) if they have a periodontal probing depth (PD) of ≥4 mm and/or clinical attachment level (CAL) of ≥3 mm in >30% of the teeth. The control group (n=25) had PD ≤3 mm and/or CAL ≤2 mm. ELISA was performed to determine the concentration of CXCL10 in saliva, serum, and GCF samples. Student's t-test was carried out to evaluate the significant difference between different groups. Spearman's correlation test was used to analyze the relationship between the levels of CXCL10 and the clinical periodontal parameters. P-value of ≤0.05 was considered significant. RESULTS: Significantly higher concentrations of CXCL10 were found in saliva and serum in chronic periodontitis patients as compared with the controls (272±60.4 pg/mL and 72±13.4 pg/mL vs 130±22.2 pg/mL and 44.08±4.5 pg/mL, P≤0.05). The CXCL10 levels in GCF were higher in the periodontitis group as compared with the control group (66.36±32.0 pg/mL and 44.56±17.5 pg/mL, respectively); the difference did not reach statistical significance (P≥0.05). Moreover, serum CXCL10 level was significantly higher in periodontitis patients with moderate to severe bone loss as compared with those with mild bone loss (71.05±4.7 pg/mL vs 54.8±7.7 pg/mL, P≤0.05). The serum CXCL10 levels were found to be related to CAL measurements (r=0.3, P=0.026), while the saliva CXCL10 levels were related to PD measurements (r=0.8, P=0.0007). CONCLUSION: CXCL10 is significantly increased in periodontitis subjects as compared with controls and could be used as a marker for periodontal disease.

Induction of IL-10 cytokine and the suppression of T cell proliferation by specific peptides from red cell band 3 and in vivo effects of these peptides on autoimmune hemolytic anemia in NZB mice.

PURPOSE: The anion channel protein band 3 is the main target of the pathogenic red blood cells (RBC) autoantibodies in New Zealand black (NZB) mice. CD4 T cells from NZB mice with autoimmune hemolytic anemia respond to band 3. Previously, we have shown that IL-10 and peptides containing a dominant T cell epitope from red cell band 3 modulate autoimmune hemolytic anemia in NZB mice. Because of the immunoregulatory role of IL-10 in autoimmune diseases, we aim to identify individual band 3 peptides that induce high IL-10 production and simultaneously suppress CD4 T cell proliferation and to investigate the effect intranasal administration of IL-10 producing band 3 peptides on autoantibody responses of NZB mice. METHODS: Splenic CD4 T cells of NZB mice were isolated and stimulated by co-culture of T cells with individual band 3 peptides. IL-10 production was measured by enzyme-linked immunosorbent assay and proliferative response of CD4 T cells was estimated by incorporation of [3H] thymidine assay. NZB mice were given either PBS, or peptides 25 (241-251) and 29 (282-296) or both peptides intranasally on three occasions at 2-day intervals. The mice were bled at 6, 10 and 18 weeks after peptide inhalation, and the number of RBC auto-antibodies was measured by DELAT and hematocrit values were assessed. RESULTS: Peptides 25 (241-251) and 29 (282-296) induced the highest IL-10 production by CD4 T cells. These peptides also inhibited the peak T cell proliferative response. 6 and 10 weeks after peptide inhalation, the total IgG, IgG1 and IgG2a in mice treated with both peptides 241-251 and 282-296 were significantly higher than control (P < 0.05). However, no significant difference in the mean hematocrit between of the peptide-treated mice and the control group was found. CONCLUSIONS: Although band 3 peptides 241-251 and 282-296 induced to the highest IL-10 production by CD4 T cells in vitro but fail to reverse the RBC autoantibody response in vivo. Modifications to improve solubility these peptides might help to modulate the immune response toward a T helper-2 profile and decrease the severity of anemia.

Opa+ and Opa- isolates of Neisseria meningitidis and Neisseria gonorrhoeae induce sustained proliferative responses in human CD4+ T cells.

T cells may interact with a number of bacterial surface antigens, an encounter which has the potential to downmodulate host immune responses. Neisseria meningitidis, a human colonizer and an agent of septicemia and meningitis, expresses Opa proteins which interact with the CEACAM1 receptor expressed on activated T cells. Since CEACAM1 can act as an inhibitory receptor and T cells in subepithelial tissues may encounter whole bacteria, which often express Opa proteins in vivo, this study assessed primarily if Opa proteins expressed on meningococci affect T-cell functions. In addition, Opa-containing outer membrane vesicles (OMV) have been used as vaccine antigens, and therefore Opa+ and Opa- OMV were also studied. While Opa+ bacteria adhered to CEACAM-expressing T cells, both the Opa+ and Opa- phenotypes induced no to a small transient depression, followed by a prolonged increase in proliferation as well as cytokine production. Such responses were also observed with heat-killed bacteria or OMV. In addition, while anti-CEACAM antibodies alone inhibited proliferation, on coincubation of T cells with bacteria and the antibodies, bacterial effects predominated and were Opa independent. Thus, while Opa proteins of N. meningitidis can bind to T-cell-expressed CEACAM1, this is not sufficient to overcome the T-cell recognition of bacterial factors, which results in a proliferative and cytokine response, an observation consistent with the ability of the host to establish lasting immunity to Opa-expressing meningococci that it frequently encounters. The data also imply that Opa-proficient vaccine preparations may not necessarily inhibit T-cell functions via CEACAM1 binding.

Role of CD4+ and CD8+ T cells in murine skin and heart allograft rejection across different antigenic desparities.

The factors that influence the relative contribution of the T cell subsets to allograft rejection remain unclear. We compared skin and heart rejection in CD4 Knockout (KO), and CD8 KO mice across full-, minor-, and class II histocompatibility antigen (HA) mismatches. Skin allografts were rejected by either CD4+ or CD8+ T cells alone at any degree of antigenic mismatch. However, either the absence of CD4+ cells or a lesser degree of HA mismatch resulted in prolongation of graft survival. In contrast, fully allogeneic heart grafts were accepted in CD4 KO recipients, and minor HA mismatched heart grafts were accepted by both CD4 KO and CD8 KO mice. Thus, the T cell subsets required for allograft rejection are determined by the immunogenicity of the tissue transplanted. In the absence of CD8+ T cells, perforin and Fas ligand (FasL) but not granzyme B mRNA were detected in rejecting grafts. Thus, granzyme B is a CD8+ cytotoxic T lymphocyte (CTL)-specific effector molecule.

Peptides containing a dominant T-cell epitope from red cell band 3 have in vivo immunomodulatory properties in NZB mice with autoimmune hemolytic anemia.

The major target of the pathogenic red blood cell (RBC) autoantibodies in New Zealand black (NZB) mice is the anion channel protein band 3, and CD4+ T cells from NZB mice respond to band 3. Here, we demonstrate that a band 3 peptide 861-875, which is the predominant sequence recognized by NZB T cells in vitro, bears a dominant helper epitope able to modulate the autoimmune hemolyic anemia in vivo. The development of RBC-bound autoantibodies and anemia was accelerated in NZB mice injected with peptide 861-874, which is relatively insoluble, and inhalation of the peptide primed T cells for both peptide 861-874 and band 3 responses. By contrast, inhalation of a soluble analog (Glu861, Lys875) of peptide 861-874 deviated the autoimmune response toward a T helper-2 (Th2) profile, with marked increases in the ratio of interleukin-4 to interferon-gamma produced by splenic T cells responding in vitro to either peptide 861-874 or band 3. Moreover, in mice that had received such treatment, the proportion of RBC-bound immunoglobulin G (IgG) molecules that were of the Th2-associated IgG1 isotype was also increased, and anemia was less severe. It is concluded that NZB autoimmune hemolytic anemia is helper dependent and that nasal administration of different peptides containing the dominant T-cell epitope can have potentially detrimental or beneficial effects on the disease.

Effector mechanisms in murine allograft rejection: comparison of skin and heart grafts in fully allogeneic and minor histocompatibility antigen-mismatched strain combinations.

Cytotoxic T lymphocytes (CTLs) and macrophage-mediated delayed-type hypersensitivity (DTH) responses may both mediate allograft rejection. Furthermore, although allograft rejection is classically considered a type [22, 23, 38, 50, 52] 1 cellular immune response, type-2 cytokines can support rejection. This study examines whether the immunogenicity of the transplanted tissue, as determined by type of tissue (skin versus heart) and degree of antigenic mismatch, influences recruitment of these effector mechanisms. Graft survival, histological appearance and intragraft gene expression (IL-2, IFN-gamma, IL-12 p40, IL-4, IL-10, perforin, Fas ligand (Fas L), iNOS and TNF-alpha) were compared for fully allogeneic, minor histocompatibility (mHC) antigen-mismatched and syngeneic skin and heart grafts. We found mRNA characteristic of CTLs and DTH responses in fully allogeneic and mHC antigen-mismatched skin and heart grafts. Concomitant type-1 and type-2 cytokine gene transcription was seen. These findings demonstrate that the tissue grafted and degree of antigenic disparity between donor and recipient do not restrict the repertoire of cellular immune responses involved in graft rejection. This finding has implications in the design of new immunosuppressive strategies for clinical transplantation.