The effects of transjugular intrahepatic portosystemic shunt on portal hypertensive gastropathy

In addition to variceal bleeding, haematemesis may occur due to haemorrhagic gastritis in patients with portal hypertension. This has been known as portal hypertensive gastropathy (PHG). We have evaluated the effects of the transjugular intrahepatic portosystemic shunt (TIPS) on portal venous pressure (PVP) and endoscopic gastric mucosal changes observed in patients with portal hypertension. We performed TIPS in 12 patients with complications due to portal hypertension as follows: variceal bleeding in nine patients (bleeding from oesophageal varices in seven and gastric varices in two), refractory ascites in three and haemorrhage from severe PHG in one. Endoscopic examinations were performed before and after TIPS for all patients. Changes of PVP and gastric mucosal findings on endoscopy were analysed. Before TIPS, PHG was seen in 10 patients. Portal venous pressure decreased from an average of 25.1+/-8.8 to 17.1+/-6.2 mmHg after TIPS (P<0.005). On endoscopy, PHG improved in nine of 10 patients. Oesophagogastric varices improved in eight of 11 patients. In one patient with massive haematemesis, haemorrhage from severe PHG completely stopped after TIPS. Because TIPS effectively reduced PVP, this procedure appeared to be effective for the treatment of uncontrollable PHG.

Clinical results of transhiatal esophagectomy for carcinoma of the lower thoracic esophagus according to biological markers

We generally choose transhiatal esophagectomy (THE) for patients with high risk for postoperative complications and for carcinoma of the lower thoracic esophagus, even if the tumor is in the advanced stage. In order to define indications for THE in esophageal cancer patients, we investigated 40 THE cancer patients according to the expressions of EGF/EGFR, p53 and p21. In patients with stage I, II, III and IV tumors, 5-year survival rates were 66.7%, 28.6%, 30.0% and 11.4%, respectively. The sites of first recurrence were the lymph nodes (n = 10) and single organs (n = 10). Dissemination (n = 3) and local recurrence (n = 2) were also seen as a first recurrence. According to EGF/EGFR, 5-year survival rate was 69% and 14% in the low and high EGF/EGFR groups, respectively. According to p53 expression, 5-year survival was 60% and 30% in the negative and positive groups, respectively; according to p21 expression, 5-year survival was 71% and 0% in the negative and positive groups, respectively. Significant difference was seen in EGF/EGFR and p21 groups. These data support less invasive surgery for some patients even for esophageal cancer patients. THE is a less invasive surgery, that also implies fewer curative procedure. Our results also showed that THE alone will be the only curative procedure necessary for some patients. We can determine therapeutic procedures using these new factors, and thus avoid unnecessary excess surgical stress in esophageal cancer patients.

[Two cases of spontaneous hemopeumothorax]

We experienced two cases of spontaneous hemopeumothorax. One case was a 17-year-old male with a complaint of back pain. A chest tube for rapid pleural evacuation disclosed hemorrhage as much as 3,000 ml, with drainage volume being gradually decreased. He needed about two month's admission because of complication of pyothorax. The other case was a 46-year-old male with a complaint of chest pain. Chest X-P gave the diagnosis of right hemopeumothorax. Thirty minutes later, he became shock, and five hours later, we performed an emergency intervention of video-assisted thoracoscopic surgery (VATS). Bleeding site of a funicular structure from the parietal pleura was stopped by clipping, with excellent postoperative results. Spontaneous hemopeumothorax is often indicated for early surgical intervention because of association with a high risk of hemorrhagic shock. In such a case, VATS is very helpful.

CD73 expression and fyn-dependent signaling on murine lymphocytes

CD73 is a glycosyl phosphatidylinositol-anchored protein with both ecto-enzyme activity (ecto-5'-nucleotidase) and signal transducing capabilities for human T lymphocytes. We now report an analysis of the distribution and function of CD73 in murine lymphoid tissues made possible by the development of the first monoclonal antibodies (mAb) specific for murine CD73. Subsets of T and B lymphocytes are CD73+ and the level of expression increases with lymphocyte maturation in both species. Among B cells, CD73 is largely restricted to cells which have undergone isotype switching. The signal transmitting function of CD73 is also conserved, as splenic T cells treated with anti-CD73 mAb plus phorbol 12-myristate 13-acetate proliferate and secrete IL-2. Fyn-/- mice are unresponsive to CD73 ligation, however, demonstrating the requirement for this tyrosine kinase in CD73-mediated signal transduction. CD73 is down-regulated after mAb plus cross-linking, suggesting that expression may be controlled by interaction with a ligand. Only small numbers of thymocytes are CD73+, so CD73 receptor functions are unlikely to be important for developing T cells. However, immunohistochemical analysis reveals that reticular and vascular cells throughout the thymus and other lymphoid tissues are markedly CD73+. Therefore, CD73 might mediate lymphocyte-stromal cell interactions or condition the local microenvironment to facilitate lymphocyte development and/or function.

[Evaluation of hepatic artery occlusion after intra-arterial infusion of SMANCS in patients with hepatocellular carcinoma]

Although intra-arterial infusion of SMANCS is effective for the treatment of hepatocellular carcinoma, injury of the hepatic artery is occasionally encountered. We analyzed 78 patients with hepatocellular carcinoma who received intraarterial infusion of SMANCS. Twenty-seven patients who were treated by epirubicin were used as a control. Complete occlusion of the right hepatic artery was induced in 15 patients who received SMANCS infusion. The average number of administrations was 1.9 in the occluded group, 1.5 in the non-occluded group, and 1.6 in the epirubicin group. There was no statistically significant difference in the dose of drugs in a single session between the three groups (3.5 +/- 1.5 ml in the occluded group, 3.6 +/- 1.5 ml in the non-occluded group and 4.2 +/- 1.2 ml in the epirubicin group), and there was no statistically significant difference in total dose between the three groups (6.8 +/- 2.6 ml in the occluded group, 5.5 +/- 3.6 ml in the non-occluded group and 6.8 +/- 4.3 ml in the epirubicin group). However, total dose per tumor volume was significantly larger in the occluded group (1.1 +/- 1.0 cm3) than in the non-occluded group (0.5 +/- 0.5 cm3) (p < 0.05). Excess infusion of SMANCS for small hepatocellular carcinomas appears to be an important factor in vascular injury.

Porphyromonas gingivalis fimbriae use beta2 integrin (CD11/CD18) on mouse peritoneal macrophages as a cellular receptor, and the CD18 beta chain plays a functional role in fimbrial signaling

In this study, we demonstrate that Porphyromonas gingivalis fimbriae use molecules of beta2 integrin (CD11/CD18) on mouse peritoneal macrophages as cellular receptors and also show that the beta chain (CD18) may play a functional role in signalling for the fimbria-induced expression of interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) genes in the cells. Using a binding assay with 125I-labeled fimbriae, we observed that fimbrial binding to the macrophages was inhibited by treatment with CD11a, CD11b, CD11c, or CD18 antibody but not by that with CD29 antibody. Western blot assays showed that the fimbriae bound to molecules of beta2 integrin (CD11/CD18) on the macrophages. Furthermore, Northern blot analyses showed that the fimbria-induced expression of IL-1beta and TNF-alpha genes in the cells was inhibited strongly by CD18 antibody treatment and slightly by CD11a, CD11b, or CD11c antibody treatment. Interestingly, intracellular adhesion molecule 1 (ICAM-1), a ligand of CD11/CD18, inhibited fimbrial binding to the cells in a dose-dependent manner. In addition, ICAM-1 clearly inhibited the fimbria-induced expression of IL-1beta and TNF-alpha genes in the cells. However, such inhibitory action was not observed with laminin treatment. These results suggest the importance of beta2 integrin (CD11/CD18) as a cellular receptor of P. gingivalis fimbriae in the initiation stage of the pathogenic mechanism of the organism in periodontal disease.

Decreased benzodiazepine receptor binding in Machado-Joseph disease

Benzodiazepine receptor binding was assessed in four Japanese men with Machado-Joseph disease.

METHODS

The distribution of benzodiazepine receptors was measured by radionuclide imaging (SPECT) after intravenous administration of 123I-iomazenil (Ro 16-0154).

RESULTS

SPECT demonstrated decreased binding throughout the cerebral cortex and cerebellum in all patients. Binding potential (receptor concentration x affinity) was diffusely decreased in cerebral cortex, thalamus, striatum and cerebellum compared with control subjects, suggesting that GABAergic function may be decreased globally in these patients. Cerebral blood flow was largely normal, and no cerebral cortical atrophy was evident on MRI.

CONCLUSION

Iodine-123-iomazenil SPECT may become a potent method for detecting impairment of the cerebral cortex even before brain perfusion SPECT or MRI can reveal early abnormalities.

Three-dimensional high-resolution dynamic contrast-enhanced MR angiography of the pelvis and lower extremities with use of a phased array coil and subtraction: diagnostic accuracy

In this study, our purpose was to compare the high-resolution contrast-material-enhanced three-dimensional subtraction MR angiography with conventional angiography for occlusive disease in the pelvic and lower extremity arteries. A three-dimensional fast-imaging with steady precession (FISP) sequence with a 256 x 512 matrix was obtained on 1.5T MR unit using a phased array coil. Twenty patients with arteriosclerotic obstructive disease underwent subtraction dynamic contrast-enhanced MR angiography. In 15 patients, three regions (pelvis, upper knee, and lower knee) were sequentially obtained after repeated injection of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). In the other five patients, one region was imaged (total of 50 examinations); a maximum-intensity projection (MIP) algorithm was used for subtracted images. All patients also underwent conventional angiography. Angiographic images were divided into several anatomical segments. Three blinded radiologists independently graded a total of 50 anatomic segments with stenotic or obstructive diseases and 90 segments without disease. Subtracted images allowed resolution of small branch vessels in all examinations, although misregistration was seen in eight examinations of five patients. All arteries larger than 1 mm in diameter were visualized on subtracted images. For detection of significant stenosis (>50%), MR angiography had 96% sensitivity and 83% specificity. The correlation coefficient of degree of agreement between MR angiography and conventional angiography was .92. Stenotic vessels tended to be overestimated. We conclude that high-resolution dynamic contrast-enhanced three-dimensional MR angiography is capable of depicting small vessel anatomy of the pelvis and lower extremities. Sequential MR angiography of different regions was feasible by repeated injection of Gd-DTPA and subtraction. This technique is highly sensitive in detecting lesions, but stenosis tended to be overestimated.

Treatment of chronic osteomyelitis using calcium hydroxyapatite ceramic implants impregnated with antibiotic

We treated eighteen patients with chronic osteomyelitis by implanting pieces of antibiotic-impregnated calcium hydroxyapatite ceramic into a cavity produced after thorough surgical excision of necrotic tissue. Within three months the infected sites had all healed. During follow-up ranging from 24 to 75 months there was no recurrence of infection. Two of the patients had infected prosthetic joints which were successfully revised. Infection was controlled and incorporation of the ceramic material into host bone was demonstrated radiographically. We recommend the use of porous pieces of calcium hydroxyapatite impregnated with antibiotic as a new system for drug delivery in the treatment of chronic osteomyelitis.

Mucin-producing tumor of the pancreas: diagnostic value of diffusion-weighted echo-planar MR imaging

PURPOSE

To determine whether diffusion-weighted echo-planar magnetic resonance (MR) imaging can help differentiate mucin-producing tumors of the pancreas from other cystic lesions.

MATERIALS AND METHODS

Diffusion-weighted echo-planar 1.5-T MR imaging was performed in patients with mucin-producing tumor (n = 15), pseudocyst (n = 15), or serous microcystic tumor (n = 2). Images were obtained with diffusion-sensitizing gradients of 30 and 300 sec/mm2. The apparent diffusion coefficient (ADC) was calculated.

RESULTS

At 30 sec/mm2, all cystic lesions had very high signal intensity. The dilated main pancreatic duct was depicted in eight patients with mucin-producing tumor and in six with pseudocyst. The mean (+/- standard deviation) ADCs of mucin-producing tumors (2.7 x 10(-3) mm2/sec +/- 0.9 x 10(-3)) and pseudocysts (3.2 x 10(-3) mm2/sec +/- 1.0 x 10(-3) were significantly lower (P < .01) than those of serous cysts or cerebrospinal fluid (5.8 x 10(-3) mm2/sec +/- 2.0 x 10(-3)). At 300 sec/mm2, cysts and the main pancreatic ducts had high signal intensity in cases of mucin-producing tumor, indicative of the presence of mucinous products in both the cystic cavity and the main pancreatic duct. The signal intensity of cystic fluid in pseudocysts was high on diffusion-weighted images, but that of the pancreatic duct was decreased (ADC = 5.1 x 10(-3) mm2/sec +/- 1.7 x 10(-3)).

CONCLUSION

Diffusion-weighted MR imaging can help characterize cystic lesions of the pancreas. Findings-suggestive of viscous fluid in mucin-producing tumors are present on such images.

Potentiation of cytotoxicity against a CEA positive cell line by the bispecific antibody OH1 using LAK cells from cancer-bearing patients

Bispecific antibody, OH1 was developed, which simultaneously recognizes CD3 on T cells and carcinoembryonic antigen (CEA) on tumor cells. Although there was not significant difference, PBMCs pretreated with OH1 showed tendency to prolong survival of KATO III-injected SCID mice compared with control groups. although cytotoxicity of LAK cells from cancer-bearing patients was suppressed compared with that of cells of healthy donors, LAK cells from the patients pretreated with OH1 showed significantly increased cytotoxicity against KATO III cells. These results suggest that OH1 could be useful in immunotherapy with LAK cells for carcinomas that express CEA on the membrane.

Multiple early gastric stump carcinomas after gastrectomy for peptic ulcer

The remnant stomach after partial gastrectomy is considered to have a predilection for the development of primary gastric carcinoma. However, early gastric stump carcinomas are uncommon because the diagnosis of gastric stump carcinoma is more difficult than that of carcinoma in the intact stomach. Triple early gastric stump carcinomas, as in the present case, are exceedingly rare and may provide some clues for further investigation of carcinogenesis in the gastric stump. We studied about the histological appearance, genetic alterations (P-53 gene, c-erbB-2 gene and K-ras gene), and expression of tumor-associated antigens (carcinoembryonic antigen, carbohydrate antigen 19-9, and sialyl-Tn) in this rare case. The three carcinomas differed from each other histologically. With respect to genetic alterations, c-erbB-2 was amplified in one lesion, but no mutations of K-ras and P-53 gene were detected. The three carcinomas also differed from each other on the expression of tumor-associated antigens. In noncancerous mucosal epithelium at the anastomosis showing hyperplasia and cystic formation of glandular epithelial cells, no genetic alterations were detected, but sialyl-Tn and carbohydrate antigen 19-9 were expressed. These results suggest that there may be different processes of carcinogenesis of the three carcinomas even though they occurred under identical environmental conditions to those that have increased cancer risk.

Blood cell precursors in context. Composition of the bone marrow microenvironment that supports B lymphopoiesis

New molecular approaches are rapidly yielding information about the composition of bone marrow and culture studies suggest possible functions for many molecules in that organ. However, the marrow is extraordinarily complex with respect to interactions between cells and their behaviour may not be adequately modeled in culture. It is becoming apparent that post-translational modifications and function of proteins can be highly influenced by the cellular and extracellular environment. Therefore, in vivo studies will continue to be important for understanding this remarkable organ.

Exogenous thrombospondin stimulates the proliferation of non-thrombospondin-producing cells

The effects of thrombospondin (TSP) on the proliferation of two different human carcinoma cell lines (KIM-1 and CW-2) were investigated. The characterization of these two carcinoma cells by immunohistochemistry using anti-TSP antibody and anti-TSP-receptor antibody showed that the KIM-1 had TSP-receptors and TSP, while the CW-2 had only TSP-receptors. The addition of exogenous TSP (10 or 20 microg/ml) to culture medium stimulated the cell proliferation of CW-2 but not that of KIM-1. The cell count for CW-2 was increased dosage-dependently from 10.3 0.6x104/ml at zero TSP concentration to 12.9 0.6x104/ml at 10 microg/ml TSP concentration and to 14.7 0. 4x104/ml at 20 microg/ml TSP (each p<0.0001). In conclusion, though TSP promoted the proliferation of non-TSP-producing cells, it did not promote proliferation of TSP-producing cells. Therefore, it is predicted that TSP was already at saturated activity concentration in the TSP-producing cell line (KIM-1).

Differences in microstructural characteristics of dense HA and HA coating

Two implant types of hydroxyapatite (HA) currently are available for dental implants: dense HA-cemented titanium (Ti) and HA-coated. It has been shown in previous reports that there are differences in the chemical and mechanical stabilities between the dense HA and HA coated. The differences are thought to be due to structural differences between the two ceramic types. The aim of this study was to investigate the differences in microstructural characteristics of currently available dense HA and HA coated implants before implantation and at periods of 3 weeks and 10 months after implantation in canine bone. X-ray diffractometry, infrared analysis, transmission electron microscopy, and energy dispersive X-ray analysis were used. The dense HA is composed of crystal grains, with a well crystallized structure of HA, closely bound to each other and approximately 0.4-0.6 micron in size. Implantation did not change the original sintered structure of the dense HA. The HA coating was composed of an amorphous phase with a Ca/P ratio of 1.46 and a crystal phase consisting of oxyhydroxyapatite, tricalcium phosphate, tetracalcium phosphate, and CaO, with a Ca/P ratio of 1.57. In the amorphous phase, compared to other portions in the amorphous phase, there were some layers with lower atomic density and with no significant difference in Ca/P ratio. After implantation, the crystallization of super fine crystals of approximately 4-5 nm in thickness occurred in the amorphous phase, and with time it progressed and spread from the surface to the deeper portion of the HA coating. A Ca/P ratio of 1.58 in the crystallized portion was close to the ratio (1.60) in the dense HA, suggesting that the super fine crystals were HA. This crystallization cannot significantly decrease the solubility of the amorphous phase portion and poses risks of stress accumulation within the coating and a decrease of binding strength between the HA coating and the substrate.

Immusorba TR and Immusorba PH: basics of design and features of functions

Immusorba was reported by Yamazaki et al. to be the world's first practical immunoadsorbent in 1982. Since then, this immunoadsorbent has accumulated an abundance of clinical achievements. Immusorba has such unique functions that it is used in treating various diseases and holds possibilities for application to more diseases. Immusorba was designed as an artificial receptor for rheumatoid factor (RF) based on structural analysis of heat-denaturated globulin. Subsequently, new substances that it can adsorb have been found as seen in reports on the adsorption performance of Immusorba to anti-acetylcholine receptor antibodies (anti-AChR Abs) and antiganglioside antibodies. Along with this, Immusorba has been used in treating a wide range of diseases. The greatest characteristic of Immusorba is that its adsorption capability is selective rather than specific, making it effective against a great number of diseases.

Histological grading of malignancy correlates with regional lymph node metastasis and survival of patients with oral squamous cell carcinoma

This study evaluated the effectiveness of certain clinical and pathologic parameters in prognosing in oral squamous cell carcinoma (O-SCC). Patients and Methods. We performed a univariate and multivariate analysis of 212 patients with O-SCC and thus determined the move valuable factors in making a prognosis. We then investigated the relationships among the various pathologic parameters and regional lymph node metastasis. Regarding the pathologic parameters, a multivariate analysis using Cox's proportional hazard model determined inflammatory infiltration, invasive tendency, necrotic tendency, mitotic figures, and vascular permeation to be significant and independent prognostic factors affecting O-SCC. In addition, such the pathologic parameters as the mode of invasion, cellular atypia, mitotic figures, a necrotic tendency and as invasive tendency all correlated with the occurrence of regional lymph node metastasis. These statistically estimated histological grading of malignancy was thus found to be clinically acceptable and useful in helping to make a prognosis of O-SCC patients.

A comparison of DAI scores and characteristics of occlusal traits in three ethnic groups of Asian origin

The Dental Aesthetic Index (DAI) is an orthodontic index based on socially defined aesthetic standards. The primary aim of this study was to compare the prevalence of malocclusion using the DAI among three ethnic groups of Asian origin; Japanese, Chinese in Taiwan and Native Americans with white Americans. A secondary goal was to consider the possibility that genetic factors might be the cause of the characteristics of malocclusion in the ethnic groups of Asian origin. Malocclusion was evaluated in 1029 Japanese and 176 Chinese in Taiwan students utilising the DAI, and the findings were compared with those of Native Americans and white Americans. The DAI values of Japanese and Native Americans were significantly higher than those of Chinese in Taiwan and white Americans. The mean DAI values showed no common tendency among the three ethnic groups. The characteristics of malocclusion in each ethnic group were also evaluated by analysis of each of the 10 DAI component scores. The results revealed common characteristics of malocclusion in the three ethnic groups of Asian origin using white Americans as the standard. The findings in the present study suggest the possibility that genetic factors might have an influence on the characteristics of malocclusion.

Characterization of the UL55 gene product of herpes simplex virus type 2

We have identified the herpes simplex virus type 2 (HSV-2) UL55 gene product using a rabbit polyclonal antiserum raised against a recombinant 6 x His-UL55 fusion protein expressed in Escherichia coli. The antiserum reacted specifically with a 23 kDa protein in HSV-2 186-infected cell lysates. The protein was not detectable in the presence of the viral DNA synthesis inhibitor phosphonoacetic acid. Indirect immunofluorescence studies localized the UL55 protein within and at the periphery of the nucleus as discrete granules at late times post-infection, and nuclear fractionation studies showed that the protein was associated with the nuclear matrix of infected cells. Moreover, these discrete regions containing the UL55 protein were found to be adjacent to compartments, designated assemblons, containing the capsid protein ICP35. However, the UL55 protein was not detected in purified virions. These results suggest that the UL55 protein of HSV-2 may play an accessory role in virion assembly or maturation.

Mouse MD-1, a molecule that is physically associated with RP105 and positively regulates its expression

RP105 is a leucine-rich repeat molecule that is expressed on mouse B cells and transmits a growth-promoting signal. An anti-RP105 Ab precipitated additional molecules as well as RP105. These molecules were found to be a mouse homologue of chicken MD-1. Chicken MD-1 was previously isolated as a v-myb-regulated gene, since its transcription increases rapidly after v-myb induction. Mouse MD-1, when transiently expressed as an epitope-tagged protein, is secreted in culture fluid but tethered to the cell surface by coexpressed RP105. An association of these molecules was confirmed by immunoprecipitation with the anti-RP105 Ab and subsequent probing of the epitope tag on MD-1. Moreover, MD-1 has an effect on the expression of RP105. In transient transfection of RP105, the percentage of RP105-positive cells increased more than twice with the coexpression of MD-1. The stable expression of MD-1 conferred approximately a sevenfold increase in cell surface RP105 on a cell line that expresses RP105 alone. Thus, MD-1 is physically associated with RP105 and is important for efficient cell surface expression.

Poor prognosis in esophageal cancer patients with postoperative complications

We investigated the relationship between postoperative complications and prognosis in esophageal cancer patients. Two hundred five patients with esophageal cancer were divided into three case groups. Group A (n = 100) consisted of cases without postoperative complications. Groups B (n = 58) and C (n = 47) consisted of cases with minor and major postoperative complications. The 5-year survival rates were 41.8%, 21.3%, and 20.2% in groups A, B, and C, respectively. There was a significant difference in the prognosis between groups A and B, and also between groups A and C. Any patients who died within 5 years without a relapse their cases were excluded from the study; the 5-year survival rates were 46.7%, 32.3%, and 22.5% in groups A, B, and C, respectively, with a significant difference between groups A and B. There were no significant differences between the three groups regarding the patient characteristics. These results therefore indicate that postoperative complications might contribute to a poor prognosis in cancer patients.

p53 protein overexpression as a predictor of the response to chemotherapy in gastric cancer

This study was performed to evaluate p53 overexpression as a predictor of the response to chemotherapy of patients with gastric cancer. The subjects comprised 20 patients with Stage IV gastric cancer and three with locally recurrent lesions, all of whom were treated with 5-fluorouracil (5-FU) plus cisplatin (CDDP) for 4 weeks. Of the total 23 patients there were 10 responders; 2 showing complete response (CR) and 8, partial response (PR). Specimens obtained by endoscopic biopsy were immunohistochemically stained using anti-p53 protein and bcl-2 protein antibody. Of the 10 responders, 7 demonstrated negative p53 staining, and of the 13 nonresponders, 11 demonstrated positive p53 staining (P = 0.013). Tissue from 3 of the responders and 7 of the nonresponders that stained for bcl-2 were positive prior to chemotherapy; however, there was no association between bcl-2 staining and chemotherapeutic effect. In conclusion, immunohistochemical identification of p53 in pretreatment tissue may represent a useful predictor for chemotherapeutic outcome in patients with gastric cancer.

Expression of recombination activating genes in germinal center B cells: involvement of interleukin 7 (IL-7) and the IL-7 receptor

Mouse germinal center (GC) B cells have been shown to undergo secondary V(D)J (V, variable; D, diversity; J, joining) recombination (receptor editing) mediated by the reexpressed products of recombination activating gene (RAG)-1 and RAG-2. We show here that interleukin (IL)-7 as well as IL-4 was effective in inducing functional RAG products in mouse IgD+ B cells activated via CD40 in vitro. Blocking of the IL-7 receptor (IL-7R) by injecting an anti- IL-7R monoclonal antibody resulted in a marked suppression of the reexpression of RAG-2 and subsequent V(D)J recombination in the draining lymph node of immunized mice, whereas RAG-2 expression was not impaired in immunized IL-4-deficient mice. Further, these peripheral B cells activated in vitro or in vivo were found to express IL-7R. These findings indicate a novel role for IL-7 and IL-7R in inducing receptor editing in GC B cells.