Induction of immune responses and prevention of alveolar bone loss by intranasal administration of mice with Porphyromonas gingivalis fimbriae and recombinant cholera toxin B subunit

INTRODUCTION: Adult periodontitis is initiated by specific periodontal pathogens represented by Porphyromonas gingivalis; however, an effective measure for preventing the disease has not yet been established. In this study, the effectiveness of a vaccine composed of fimbriae of P. gingivalis and recombinant cholera toxin B subunit (rCTB) was evaluated using BALB/c mice. METHODS: Fimbriae and rCTB were co-administered intranasally to BALB/c mice on days 0, 14, 21, and 28. On day 35, mice were sacrificed to determine immunoglobulin levels in serum, saliva, and nasal and lung extracts by enzyme-linked immunosorbent assay. The prevention effect of the vaccine on P. gingivalis-induced periodontitis in mice was evaluated by measuring alveolar bone loss. RESULTS: The rCTB significantly increased serum immunoglobulin (Ig)A levels when mice were administered with a minimal amount (0.5 microg) of the fimbrial antigen. The adjuvant effect on serum IgG production was indistinct because the minimal amount of the antigen still induced a large amount of IgG. In contrast to systemic responses, a fimbria-specific secretory IgA response was strongly induced by co-administration of rCTB and 0.5 microg fimbriae; the same amount of the antigen alone scarcely induced a response. Histopathological examination revealed IgA-positive plasma cells in the nasal mucosal tissue but no observable mast cells in the area. In addition, nasal administration of the fimbrial vaccine significantly protected the mice from P. gingivalis-mediated alveolar bone loss. CONCLUSION: Nasal vaccination with a combination of fimbriae and rCTB can be an effective means of preventing P. gingivalis-mediated periodontitis.     

CD64 Surface Expression on Neutrophils and Monocytes Is Significantly Up-Regulated after Stimulation with Granulocyte Colony-Stimulating Factor during CHOP Chemotherapy for Patients with Non-Hodgkin’s Lymphoma

The present study was performed to examine whether the expression of CD64 Fc gamma receptor type I (FcgammaRI) on both neutrophils and monocytes can be modulated by multiple daily administrations of granulocyte colony-stimulating factor (G-CSF) to patients with non-Hodgkin's lymphoma in neutropenia caused by CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy. The expression of CD64 was determined by flow cytometric analysis at the following time points: before chemotherapy, at the nadir of the neutrophil count, at the fifth day after the start of G-CSF administration, and at more than 8 days after the start of G-CSF administration. CD64 expression was enhanced in patients given G-CSF during CHOP treatment, whereas CD64 expression remained unchanged in patients not given G-CSF CD64 expression levels on both neutrophils and monocytes were significantly up-regulated by the daily administration of G-CSF and reached peak levels at day 5 (P = .0007). Thereafter, expression on both cell types remained at almost the same levels as on day 5 for the rest of the treatment course, even though G-CSF therapy continued for 3 to 5 more days. Interestingly, CD64 expression on monocytes was already increased significantly (P = .0001) at the nadir of the neutrophil count relative to the baseline before chemotherapy and then was additionally up-regulated by day 5 after the start of G-CSF injections (P = .019). In antibody-dependent cellular cytotoxicity assays, we found that rituximab-mediated cell lysis was significantly enhanced at day 5 after the start of G-CSF treatment (P = .01). In conclusion, this study shows that multiple doses of G-CSF administered to lymphoma patients with neutropenia due to CHOP chemotherapy can enhance CD64 expression on both neutrophils and monocytes. Peak CD64 levels are reached at day 5 of G-CSF treatment, resulting in an activation of the rituximab-mediated antitumor ability of these effector cells. This finding may be useful in determining the optimal timing of administration for an antibody such as rituximab in a chemotherapeutic strategy designed to exert a maximal effect against tumor cells.     

Inclusion of a universal tetanus toxoid CD4 T cell epitope P2 significantly enhanced the immunogenicity of recombinant rotavirus ΔVP8* subunit parenteral vaccines

Currently available live oral rotavirus vaccines, Rotarix^® and RotaTeq^®, are highly efficacious in developed countries. However, the immunogenicity and efficacy of such vaccines in some developing countries are low. We reported previously that bacterially-expressed rotavirus ΔVP8* subunit vaccine candidates with P[8], P[4] or P[6] specificity elicited high-titer virus neutralizing antibodies in animals immunized intramuscularly. Of note was the finding that antibodies induced with the P[8]ΔVP8* vaccine neutralized both homotypic P[8] and heterotypic P[4] rotavirus strains to high titer. To further improve its vaccine potential, a tetanus toxoid universal CD4⁺ T cell epitope P2 was introduced into P[8] or P[6]ΔVP8* construct. The resulting recombinant fusion proteins expressed in Escherichia coli were of high solubility and were produced with high yield. Two doses (10 or 20 μg/dose) of the P2-P[8]ΔVP8* vaccine or P2-P[6]ΔVP8* vaccine with aluminum phosphate adjuvant elicited significantly higher geometric mean homologous neutralizing antibody titers than the vaccines without P2 in intramuscularly immunized guinea pigs. Interestingly, high levels of neutralizing antibody responses induced in guinea pigs with 3 doses of the P2-P[8]ΔVP8* vaccine persisted for at least 6 months. Furthermore, in the gnotobiotic piglet challenge study, three intramuscular doses (50 μg/dose) of the P2-P[8]ΔVP8* vaccine with aluminum phosphate adjuvant significantly delayed the onset of diarrhea and significantly reduced the duration of diarrhea and the cumulative diarrhea score after oral challenge with virulent human rotavirus Wa (G1P[8]) strain. The P2-P[8]ΔVP8* vaccine induced serum virus neutralizing antibody and VP4-specific IgG antibody production prechallenge, and primed the pigs for higher antibody and intestinal and systemic virus-specific IFN-γ producing CD4⁺ T cell responses postchallenge. These two subunit vaccines could be used at a minimum singly or preferably in bivalent formulation to provide antigenic coverage of most of the G types of global importance.     

Left non-recurrent inferior laryngeal nerve in a patient with right-sided aortic arch and aberrant left subclavian artery

Non-recurrent inferior laryngeal nerve (NRILN) is rare but one of the important anatomical variations in thyroid and parathyroid surgery. Almost all cases were observed on the right side with aberrant right subclavian artery and left NRILN have been reported in only five cases so far. Here, we reported a 38 year-old Japanese male with left NRILN accompanying adenomatous goiter. He was referred to our hospital for the surgical treatment of left thyroid goiter. Preoperative computed tomography revealed right-sided aortic arch and aberrant left subclavian artery with no signs of complete situs inversus viscerum, suggesting possible left NRLN. Left hemithyroidectomy was performed using nerve monitoring system. Intraoperatively, left recurrent laryngeal nerve was not identified along tracheoesophageal groove, but directly originated from vagal nerve and was running horizontally to larynx. Mobility of vocal cords were not impaired and postoperative course was uneventful. During thyroid surgery for the patients with right-sided aortic arch, meticulous care should be taken using nerve monitoring system to avoid nerve injury.