Preclinical evaluation of an immunotherapeutic peptide comprising 7 T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen allergens

BACKGROUND

Peptide immunotherapy is a new approach to treating allergic diseases, but a therapeutic peptide for Japanese cedar pollinosis has not yet been developed.

OBJECTIVE

The aim of this study is to prepare and preclinically evaluate a hybrid peptide comprising 7 T-cell determinants of Cry j 1 and Cry j 2, the major Japanese cedar pollen allergens.

METHODS

The recombinant hybrid peptide was prepared after immunodominance of 7 T-cell determinants was confirmed by means of PBMC proliferation assay in 113 volunteers with pollinosis. The hybrid peptide was compared with a mixture of the 7 T-cell determinants in a dose-dependent PBMC proliferation assay in 6 volunteers with pollinosis. PBMC proliferation and binding activity of serum IgE antibody against the hybrid peptide, Cry j 1, and Cry j 2 were investigated in 48 volunteers with pollinosis.

RESULTS

The hybrid peptide induced T-cell proliferation with an average 100-fold lower concentration than a mixture of the 7 peptides. PBMCs from 44 (92%) of 48 volunteers proliferated against the hybrid peptide, with significant correlation (r = 0.87) in T-cell proliferation against Cry j 1 and Cry j 2. No serum IgE antibodies specific to Cry j 1 or Cry j 2 bound to the hybrid peptide.

CONCLUSION

A hybrid peptide comprising 7 T-cell determinants has the potential for inducing T-cell proliferative responses that is superior to the potential of a mixture of the T-cell determinants and comparable with that of Cry j 1 and Cry j 2. The hybrid peptide will be of use in specific immunotherapy against Japanese cedar pollinosis.

Therapeutic Effect of Novel Anti-Human Fas Antibody HFE7A on Graft-versus-Host Disease Model

In order to evaluate anti-human Fas antibody, we have established a new graft-versus-host disease (GVHD) model wherein splenocytes of human Fas transgenic mice (hFas-TgM) were transferred to immune-deficient SCID mice. In this model, although host SCID cells are not activated by or responsive to graft hFas-TgM cells, graft hFas-TgM cells are activated by and responsive to host SCID cells and thus cause GVHD symptoms. SCID mice that received hFas-TgM splenocytes had increased human Fas-positive lymphocytes in lymph nodes, decreased in body weight, and developed skin diseases, including rash and alopecia. Administration of novel anti-human Fas antibody HFE7A, which did not induce liver toxicity after administration to mice, decreased the level of the human Fas-positive lymphocytes, blocked the decrease of body weight, and suppressed development of skin diseases in this model. These results indicate that induction of apoptosis to activated graft cells with nontoxic anti-Fas antibody could reduce GVHD symptoms.

Effect of trabecular bone contour on ultimate strength of lumbar vertebra after bilateral ovariectomy in rats

To test the hypothesis that the effect of trabecular microarchitecture on bone strength varies with the duration of estrogen loss, we evaluated the relationship between three-dimensional (3D) parameters for trabecular microarchitecture and bone minerals with the compressive load of the lumbar vertebra in rats. Female Sprague-Dawley rats (n = 190) were divided into 19 groups. Ten rats were killed at day 0. Half of the remaining rats underwent bilateral ovariectomy (ovx), and the others were subjected to sham surgery. Ten rats from each group were killed at 3, 7, 11, 14, 28, 42, 56, 70, and 84 days postsurgery. Urinary deoxypyridinoline and serum osteocalcin increased significantly in the ovx group from days 28 and 11, respectively, compared with the sham group. Bone mineral content (BMC) and bone mineral density (BMD) of the fifth lumbar body diminished from days 42 and 84, respectively, compared with the sham group. In ovx rats, trabecular bone volume (BV/TV), measured using 3D images of microcomputed tomography, diminished from day 28 compared with both baseline control and sham. The trabecular bone pattern factor (TBPf) and structure model index (SMI) increased from day 28 in the ovx group compared with both baseline control and sham. Ultimate compression loads diminished at day 28 compared with baseline control and decreased progressively thereafter. Neither of these parameters changed in the sham group during the same period. Within 4 weeks post-ovx, TBPf, SMI, and BV/TV correlated with load (p < 0.01). BMC and BMD correlated with load from 6 weeks post-ovx (p < 0.01). Stepwise regression analysis showed that TBPf was the most significant determinant of load within 4 weeks post-ovx (coefficient of determination [R(2)] = 0.669; p < 0.01). SMI correlated with TBPf (R(2) = 0.968; p < 0.01). Moreover, R(2) for ultimate load indicated higher values of 0.975 with TBPf and SMI. However, BMC was the most significant determinant of load from 6 weeks post-ovx (R(2) = 0.511; p < 0.01), as it was in the sham group. These data suggest that changes in trabecular bone contour with increased bone turnover are critical for reducing lumbar bone strength during the early post-ovx period in rats.

Therapeutic effect of anti-Fas antibody on a collagen induced arthritis model

OBJECTIVE

To investigate the therapeutic effect of anti-Fas monoclonal antibody (Mab, RK-8) in collagen induced arthritis (CIA).

METHODS

CD1F1 mice were immunized with bovine type II collagen to induce CIA and were treated with RK-8 intravenously. The effect of RK-8 was monitored by visual scoring. ELISA to detect serum anti-type II collagen antibody was performed on Day 47 and 70. Histopathological analysis was performed on Days 31 and 72. Digital micrography was performed on Day 72.

RESULTS

RK-8 treatment almost completely prevented CIA. This suppressive effect continued after RK-8 was discontinued. RK-8 significantly suppressed the serum anti-type II collagen antibody level on Day 47. Histological analysis revealed that RK-8 significantly reduced joint histopathology, as determined by the infiltration of inflammatory cells and cartilage damage, consistent with digital micrography.

CONCLUSION

Administration of anti-Fas Mab may be a useful therapeutic strategy for rheumatoid arthritis if used early in the disease.

Seasonal changes of humoral and cellular immune responses to Japanese cedar (Cryptomeria japonica) pollen allergens in Japanese monkeys (Macaca fuscata) with pollinosis

The natural occurrence of Japanese cedar [Cryptomeria japonica (CJ)] pollinosis has been reported in Japanese monkeys (Macaca fuscata). The present study was designed to investigate seasonal changes in immunological reactions to CJ pollen allergens in monkeys with CJ pollinosis. Blood samples were collected from six monkeys with CJ pollinosis before and after CJ pollen season. Seasonal changes in specific IgE and IgG to major allergens (Cry j 1 and Cry j 2) were observed before and after CJ pollen season. The humoral responses decreased significantly before CJ pollen and increased after CJ pollen season. Similar seasonal changes in peripheral blood mononuclear cells proliferative responses to CJ allergens were observed before and after CJ pollen season. These humoral and cellular immune responses might serve as a biomarker for assessing new immunotherapies for monkeys with pollinosis.

A novel glucokinase regulator in pancreatic beta cells: precursor of propionyl-CoA carboxylase beta subunit interacts with glucokinase and augments its activity

A glucokinase regulatory protein has been reported to exist in the liver, which suppresses enzyme activity in a complex with fructose 6-phosphate, whereas no corresponding protein has been found in pancreatic beta cells. To search for such a protein in pancreatic beta cells, we screened for a cDNA library of the HIT-T15 cell line with the cDNA of glucokinase from rat islet by the yeast two hybrid system. We detected a cDNA encoding the precursor of propionyl-CoA carboxylase beta subunit (pbetaPCCase), and glutathione S-transferase pull-down assay illustrated that pbetaPCCase interacted with recombinant rat islet glucokinase and with glucokinase in rat liver and islet extracts. Functional analysis indicated that pbetaPCCase decreased the K(m) value of recombinant islet glucokinase for glucose by 18% and increased V(max) value by 23%. We concluded that pbetaPCCase might be a novel activator of glucokinase in pancreatic beta cells.

Increased susceptibility to chemotherapeutic alkylating agents of mice deficient in DNA repair methyltransferase

O(6)-methylguanine-DNA methyltransferase plays vital roles in preventing induction of mutations and cancer as well as cell death related to alkylating agents. Mice defective in the MGMT: gene, encoding the methyltransferase, were used to evaluate cell death-inducing and tumorigenic activities of therapeutic agents which have alkylation potential. MGMT(-/-) mice were considerably more sensitive to dacarbazine, a monofunctional triazene, than were wild-type mice, in terms of survival. When dacarbazine was administered i.p. to 6-week-old mice and survival at 30 days was enumerated, LD(50) values of MGMT(-/-) and MGMT(+/+) mice were 20 and 450 mg/kg body wt, respectively. Increased sensitivity of MGMT(-/-) mice to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosou rea (ACNU), a bifunctional nitrosourea, was also noted. On the other hand, there was no difference in survival of MGMT(+/+) and MGMT(-/-) mice exposed to cyclophosphamide, a bifunctional nitrogen mustard. It appears that dacarbazine and ACNU produce O(6)-alkylguanine as a major toxic lesion, while cyclophosphamide yields other types of modifications in DNA which are not subjected to the action of the methyltransferase. MGMT(-/-) mice seem to be less refractory to the tumor-inducing effect of dacarbazine than are MGMT(+/+) mice. Thus, the level of O(6)-methylguanine-DNA methyltransferase activity is an important factor when determining susceptibility to drugs with the potential for alkylation.

Abnormal myocardial blood flow distribution in patients with angina pectoris and normal coronary arteriograms

To evaluate coronary microvascular function and its relation to the genesis of chest pain and ST-segment depression during exercise in patients with syndrome X, pacing-induced changes in transmural myocardial blood flow distribution were quantitatively assessed by 2-dimensional myocardial contrast echocardiography. Of 25 patients with a history of chest pain and normal coronary arteries with the negative ergonovine test, 11 had exercise-induced chest pain and ST-segment depression (syndrome X), and 14 did not (controls). Myocardial blood flow distribution before and after pacing stress was assessed by measuring the ratio of the endocardial to epicardial gray level (ie, endo/epi gray level ratio) in the territory of the left anterior descending coronary artery. Pacing-induced chest pain and ST-segment depression were observed in syndrome X, but not in controls. The endo/epi gray level ratio in syndrome X significantly decreased after pacing (from 0.98+/-0.10 to 0.76+/-0.17, p<0.01), but not in controls (from 0.97+/-0.08 to 0.99+/-0.08, NS). Abnormal myocardial blood flow distribution may play an important role in exercise-induced chest pain and ST-segment depression in these patients.

The prodomain of caspase-1 enhances Fas-mediated apoptosis through facilitation of caspase-8 activation

Caspase-1 (interleukin-1beta converting enzyme) is produced in the form of a latent precursor, which is cleaved to yield a prodomain in addition to the p20 and p10 subunits. It has been established that the (p20/p10)(2) heterotetramer processes the latent precursor of interleukin-1beta into an active form during apoptosis, but the function of the residual prodomain of caspase-1 (Pro-C1) has not been established. To evaluate the involvement of Pro-C1 in apoptosis, a Pro-C1 expression vector was transfected into the HeLa cell line, which is susceptible to Fas-mediated apoptosis. Expression of recombinant Pro-C1 in HeLa cells enhanced apoptosis mediated by Fas, but not etoposide-induced apoptosis. This enhancement of Fas-mediated apoptosis was abolished by inhibitors of caspase-8 (Ile-Glu-Thr-Asp-fluoromethyl ketone) and caspase-3 (Asp-Glu-Val-Asp-aldehyde) but was only slightly diminished by an inhibitor of caspase-1 (acetyl-Tyr-Val-Ala-Asp-chloromethyl ketone). During apoptosis induced by an agonistic anti-Fas antibody, the activation of caspase-8 and caspase-3 was more pronounced and occurred more rapidly in HeLa/Pro-C1 cells than in the empty vector transfectant (HeLa/vec) cells; in contrast, caspase-1 was not activated in either HeLa/Pro-C1 or HeLa/vec cells. These results demonstrate an additional and novel function for caspase-1 in which Pro-C1 acts to enhance Fas-mediated apoptosis, most probably through facilitation of the activation of caspase-8.

Alfacalcidol inhibits bone resorption and stimulates formation in an ovariectomized rat model of osteoporosis: distinct actions from estrogen

Although alfacalcidol has been widely used for the treatment of osteoporosis in certain countries, its mechanism of action in bone, especially in the vitamin D-replete state, remains unclear. Here we provide histomorphometric as well as biochemical evidence that alfacalcidol suppresses osteoclastic bone resorption in an ovariectomized rat model of osteoporosis. Furthermore, when compared with 17beta-estradiol, a representative antiresorptive drug, it is evident that alfacalcidol causes a dose-dependent suppression of bone resorption, and yet maintains or even stimulates bone formation, as reflected in increases in serum osteocalcin levels and bone formation rate at both trabecular and cortical sites. 17beta-Estradiol, which suppresses bone resorption to the same extent as alfacalcidol, causes a parallel reduction in the biochemical and histomorphometric markers of bone formation. As a final outcome, treatment with alfacalcidol increases bone mineral density and improves mechanical strength more effectively than 17beta-estradiol, with a more pronounced difference in cortical bone. We conclude that estrogens depress bone turnover primarily by suppressing bone resorption and, as a consequence, bone formation as well, whereas alfacalcidol "supercouples" these processes, in that it suppresses bone resorption while maintaining or stimulating bone formation.

A novel murine anti-human Fas mAb which mitigates lymphadenopathy without hepatotoxicity

Defects in Fas-mediated apoptosis are implicated in autoimmune diseases including rheumatoid arthritis (RA). Although induction of Fas-mediated apoptosis could have therapeutic effects on these diseases, it might cause deleterious effects in liver as Fas ligand or an agonistic anti-murine Fas antibody Jo2 causes severe hepatic injury in mice. We report here on the interesting characteristics of the newly obtained anti-Fas mAb, HFE7A, which cross-reacts with the Fas molecules of various species ranging from human to mouse and mitigates autoimmune symptoms without hepatotoxicity in mice. The administration of HFE7A to mice induced apoptosis in the thymocytes, although administration of HFE7A to mice or to marmosets did not induce any sign of hepatitis. The effect of HFE7A on liver is different from that of anti-murine Fas antibody Jo2, which causes acute and lethal hepatic injury to mice. Administration of HFE7A reduced lymphadenopathy and abnormal T cells in MRL-gld/gld mice. HFE7A induced apoptosis in synovial cells prepared from RA patients. Surprisingly, HFE7A protected mice from fulminant hepatitis induced by Jo2. Therefore, HFE7A is a potential therapeutic antibody not only for autoimmune diseases including RA but also for fulminant hepatitis.

The advantage of alfacalcidol over vitamin D in the treatment of osteoporosis

Although alfacalcidol is widely used in the treatment of osteoporosis, its mechanism of action in bone is not fully understood. Alfacalcidol stimulates intestinal calcium (Ca) absorption, increases urinary Ca excretion and serum Ca levels, and suppresses parathyroid hormone (PTH) secretion. It remains to be clarified, especially under vitamin D-replete conditions, whether alfacalcidol exerts skeletal effects solely via these Ca-related effects, whether the resultant suppression of PTH is a prerequisite for the skeletal actions of alfacalcidol, and, by inference, whether alfacalcidol has an advantage over vitamin D in the treatment of osteoporosis. To address these issues, we (1) compared the effects of alfacalcidol p.o. (0.025-0.1 microg/kg BW) vis-à-vis vitamin D(3) (50-400 microg/kg BW) on bone loss in 8-month-old, ovariectomized (OVX) rats as a function of their Ca-related effects, and (2) examined whether the skeletal effects of alfacalcidol occur independently of suppression of PTH, using parathyroidectomized (PTX) rats continuously infused with hPTH(1-34). The results indicate that (1) in OVX rats, alfacalcidol increases BMD and bone strength more effectively than vitamin D(3) at given urinary and serum Ca levels: larger doses of vitamin D(3) are required to produce a similar BMD-increasing effect, in the face of hypercalcemia and compromised bone quality; (2) at doses that maintain serum Ca below 10 mg/dl, alfacalcidol suppresses urinary deoxypyridinoline excretion more effectively than vitamin D(3); and (3) alfacalcidol is capable of increasing bone mass in PTX rats with continuous infusion of PTH, and therefore acts independently of PTH levels. It is suggested that alfacalcidol exerts bone-protective effects independently of its Ca-related effects, and is in this respect superior to vitamin D(3), and that the skeletal actions of alfacalcidol take place, at least in part, independently of suppression of PTH. Together, these results provide a rationale for the clinical utility of alfacalcidol and its advantage over vitamin D(3) in the treatment of osteoporosis.

The incidence of Japanese cedar pollinosis and sensitization to the pollen allergens among Japanese monkeys in a troop

The natural occurrence of Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata), an appropriate animal model for developing antipollinosis therapies. However, there has been no study on the incidence of Japanese cedar pollinosis in monkeys. To evaluate the incidence of CJ pollinosis in Japanese monkeys, we investigated the presence of pollinosis symptoms among monkeys in a troop, and the response to CJ allergens in pollinosis monkeys. We examined the presence of pollinosis symptoms in 272 monkeys in a troop throughout the CJ pollination season (February to April). Of the 272 monkeys, 21 (7.7%) showed pollinosis symptoms during the CJ pollen season. Blood samples were taken from the 21 monkeys that showed pollinosis symptoms and were tested for the presence of immunoglobulin E (IgE) antibody for CJ allergens. All 21 monkeys with CJ pollinosis had anti-CJ IgE. Of the 21 monkeys, peripheral blood mononuclear cells (PBMC) could be taken from 12, all of which showed CJ allergen-specific PBMC proliferation. The incidence of CJ pollinosis in a troop was 7.7%. The monkeys with CJ pollinosis demonstrated specific IgE and PBMC proliferation for CJ allergens.

The incidence of japanese cedar pollinosis and sensitization to the pollen allergens among Japanese monkeys in a troop

The natural occurrence of Japanese cedar (Cryptomeria japonica; CJ) pollinosis has been reported in Japanese monkeys (Macaca fuscata), an appropriate animal model for developing antipollinosis therapies. However, there has been no study on the incidence of Japanese cedar pollinosis in monkeys. To evaluate the incidence of CJ pollinosis in Japanese monkeys, we investigated the presence of pollinosis symptoms among monkeys in a troop, and the response to CJ allergens in pollinosis monkeys. We examined the presence of pollinosis symptoms in 272 monkeys in a troop throughout the CJ pollination season (February to April). Of the 272 monkeys, 21 (7.7%) showed pollinosis symptoms during the CJ pollen season. Blood samples were taken from the 21 monkeys that showed pollinosis symptoms and were tested for the presence of immunoglobulin E (IgE) antibody for CJ allergens. All 21 monkeys with CJ pollinosis had anti-CJ IgE. Of the 21 monkeys, peripheral blood mononuclear cells (PBMC) could be taken from 12, all of which showed CJ allergen-specific PBMC proliferation. The incidence of CJ pollinosis in a troop was 7.7%. The monkeys with CJ pollinosis demonstrated specific IgE and PBMC proliferation for CJ allergens.

[Diagnosis of breast cancer extent and enhancement patterns using 3D-dynamic MR imaging: correlation with intraductal component]

The usefulness of 3D-dynamic MR imaging with fat suppression and magnetization transfer contrast for assessing breast cancer extent and tumor profile was evaluated in 74 breasts with 67 malignant and 7 benign lesions. We classified breast cancer by the intraductal component of the main tumor. Five histological types were assigned: type 1 (DS 0) invasive carcinoma without intraductal component, type 2 (DS 1): intraductal component is less than 50% of whole tumor, type 3 (DS 2): intraductal component is nearly equal to 50%, type 4 (DS 3): intraductal component is more than 50%, type 5 (DS 4): pure DSIC or DCIS associated with microinvasive foci. Histologic results and preoperative MR imaging were analyzed regarding tumor size and enhancement pattern for the various tumor types (DS 0, 1, 2, 3 and 4). The three tumors occult to MR imaging were two DCIS and one Paget's disease. The other 64 breast cancers were detected on MR imaging. Tumor size measured with MR imaging correlated closely with histologic measurement in DS 0, 1 and 2, whereas less accuracy was noted in DS 3 and 4. Rapid enhancement was frequently seen in DS 0, 1, 2 and 3. Peripheral enhancement was highly specific for breast cancer. However, peripheral enhancement was not found in all cases of DS 4. Linear and nodular enhancement was frequently seen in DS 3 and 4. MR imaging was useful in predicting the intraductal component.

Identification of the cornea-specific keratin 12 promoter by in vivo particle-mediated gene transfer

PURPOSE

Keratin 12 (K12) is a cornea epithelial cell-specific intermediate filament component. To provide a better understanding of its expression, it is necessary to identify and characterize the promoter of Krt1.12 gene.

METHODS

The 2.5-kb DNA 5' to Krt1.12 gene was sequenced. Krt1.12 promoter-beta-gal DNA constructs were prepared and used in vivo to transfect rabbit corneas, conjunctivas, and skin by particle-mediated gene transfer (Gene Gun). In vitro, the DNA constructs were transfected into cultured T-antigen-transformed rabbit corneal epithelial (RCE-T) cells and human fibrosarcoma HT-1080 fibroblasts with lipofectamine. The promoter activity was assessed by measuring beta-gal (beta-galactosidase) activity using histochemical staining with 5-Bromo-4-chloro-3-indolyl-beta-D-galactoside and enzyme assay with o-nitrophenyl beta-D-galactopyranoside.

RESULTS

There are four Pax-6 pair box binding elements found between -910 and -2000 bp 5'-flanking the transcription initiation site of the Krt1.12 gene. None of promoter constricts can be expressed by HT-1080 cells. Cotransfection of Pax-6 cDNA with K12 promoter-beta-gal constructs containing Pax-6 elements results in a fourfold increase of beta-gal activities in RCE-T cells but not HT-1080 fibroblasts. The data of in vivo transfection in the rabbit by Gene Gun indicate that reporter gene constructs containing 0.6-kb and longer DNA fragments 5'-flanking Krt1.12 gene are effectively expressed in corneal, but not conjunctival or epidermal epithelial cells.

CONCLUSIONS

The particle-mediated gene transfer is a suitable technique for in vivo delivery of transgenes to corneal epithelial cells. The 2.5-kb DNA fragment 5'-flanking Krt1.12 contains corneal epithelial cell-specific regulatory cis-DNA elements. Pax-6 is a positive transcription factor essential for keratin 12 expression.

Syntheses and preventive effects of analogues related to 1alpha,25-dihydroxy-2beta-(3-hydroxypropoxy)vitamin D3 (ED-71) on bone mineral loss in ovariectomized rats

Analogues related to 1alpha,25-dihydroxy-2beta-(3-hydroxypropoxy)vitamin D3 (ED-71) (2), 26,27-dimethyl ED-71 (3) and 26,27-diethyl ED-71 (4), were synthesized from lithocholic acid (5). In the study of the preventive effects of these analogues and ED-71 (2) on bone mineral loss in ovariectomized rats, 26,27-dimethyl ED-71 (3) showed the most potent activity.

Oral administration of a dominant T-cell determinant peptide inhibits allergen-specific TH1 and TH2 cell responses in Cry j 2-primed mice

BACKGROUND

Oral immunotherapy with a peptide for allergic immune responses is theoretically a promising therapy but has not been established yet.

OBJECTIVE

To evaluate immune suppressive efficacy of oral administration of an immunodominant peptide, we investigated changes in T-cell proliferation, TH1 - and TH2 -cytokine production, and TH1 - and TH2 -mediated antibody production in mice after oral administration of a peptide.

METHODS

Peptide p246-259, containing a dominant T-cell determinant of Cry j 2, which is the major allergen in Japanese cedar pollen, was used in this study. Groups of mice received p246-259 or PBS alone before or after they were primed intranasally with Cry j 2 and cholera toxin. In another experiment mice were primed intraperitoneally with Cry j 2 and alum. Proliferative response and cytokine production by nasal-associated lymph node cells against Cry j 2 were investigated. Amounts of systemic anti-Cry j 2 IgE and IgG antibodies were also measured.

RESULTS

Oral administration of the peptide to mice before, or even after, the sensitization induced oral tolerance in T-cell responses against the allergen; the tolerance was associated with decreased production of TH1 (IFN-gamma and IL-2) and TH2 (IL-4) cytokines. Allergen-specific TH1 -mediated (IgG2a and IgG2b) and TH2 -mediated (IgG1 and IgE) antibody responses were also inhibited.

CONCLUSIONS

Oral administration of a dominant T-cell determinant peptide induces immunologic tolerance in both TH1 and TH2 cell responses against the whole protein allergen. Our study is the first, to our knowledge, to demonstrate the potential for peptide-based oral immunotherapy in order to treat allergic immune responses.

Analysis of the ternary complex formation of human urokinase with the separated two domains of its receptor

Human urokinase-type-plasminogen-activator receptor (uPAR) is a glycolipid-anchored membrane glycoprotein comprising three structurally similar domains. We have succeeded in direct observation of the ternary complex formation of single-chain urokinase (scuPA) or its N-terminal fragment (ATF) with the separated domain-1 (N-terminal domain) and domain-(2+3) (internal and C-terminal domain) of human uPAR, by means of gel-filtration HPLC analysis. This complex was found to consist of the three components in an equimolar ratio (thus referred to as the three-part complex). To determine the nature of the interaction between these components, cross-linking experiments involving various kinds of cross-linkers and competitive binding assay on ELISA were performed. These experiments have shown that each uPAR domain can bind directly to scuPA at low affinity, and that both these domains contribute to the high-affinity binding between scuPA and uPAR in a synergistic manner. It can be considered that the synergistic effect of domain-1 and domain-(2+3) on scuPA binding would result from a conformational change, and that this steric event might trigger the signal transduction reported for scuPA/uPAR binding.

The cloning of mouse keratocan cDNA and genomic DNA and the characterization of its expression during eye development

Keratan sulfate proteoglycans (KSPGs) play a pivotal role in the development and maintenance of corneal transparency. Keratocan, lumican, and mimecan (osteoglycin) are the major KSPGs in vertebrate corneas. To provide a better understanding of the structure/function relationship of keratocan, we have cloned both the mouse keratocan gene and its cDNA. We have also examined its expression during embryonic development. The mouse keratocan gene spans approximately 6.5 kilobases of the mouse genome and contains three exons and two introns. Northern blotting and in situ hybridization were employed to examine keratocan gene expression during mouse development. Unlike lumican gene, which is expressed by many tissues other than cornea, keratocan mRNA is more selectively expressed in the corneal tissue of the adult mouse. During embryonic development, keratocan mRNA was first detected in periocular mesenchymal cells migrating toward developing corneas on embryonic day 13.5 (E13.5). Its expression was gradually restricted to corneal stromal cells on E14. 5 approximately E18.5. Interestingly, keratocan mRNA can be detected in scleral cells of E15.5 embryos, but not in E18.5 embryos. In adult eyes, keratocan mRNA can be detected in corneal keratocytes, but not in scleral cells.

Induction of oral tolerance in splenocyte-reconstituted SCID mice

The participation of each lymphocyte compartment in the induction of oral tolerance for antibody response was investigated by means of a new cell-transfer experimental system, using severe combined immunodeficiency (SCID) mice. Various lymphocyte compartments from BALB/c mice were transferred into SCID mice and these mice were evaluated for oral tolerance induction. First, whole splenocytes from BALB/c mice were transferred into SCID mice and these mice were orally administered bovine alpha s1-casein. The specific antibody response in these mice after subsequent immunization with antigen was greatly reduced compared to controls which were not fed the antigen, and it was demonstrated that oral tolerance was induced in SCID mice bearing donor splenocytes. Oral tolerance was induced in SCID mice that were reconstituted with only T cells, revealing that B cells were not required for the induction of oral tolerance. Further, oral tolerance was induced in SCID mice reconstituted with CD8-depleted splenocytes but not in mice reconstituted with only CD8+ T cells. These results demonstrate that oral tolerance could be induced in SCID mice bearing normal splenocytes and that interaction of CD4+ T cells with antigen-presenting cells other than B cells are responsible for the induction of oral tolerance. Our experimental system may be useful for investigations with human lymphocytes.

Characterization of Bsk mice: I. The Bsk mutation does not involve a recombination of cornea-specific keratin 12 and skin-specific hair keratin genes

PURPOSE

Bsk (bare skin) is an autosomal dominant mutation linked to the Krt 1 (type 1 keratin) locus of mouse chromosome 11. The adult Bsk mouse manifests hair loss and corneal opacity. To identify and characterize the keratin genes involved in this mutation, we examined the hypothesis proposing that the Bsk mutation might involve a recombination event between cornea-specific (K12) and hair-specific (mHa 1, 2, 3 and 4) type I keratin genes.

METHODS

The Bsk phenotype was examined by histochemical analysis, using light and electron microscopy. RFLP was used for their genotyping, and possible keratin gene expression was examined by immunohistochemical staining, Western analysis, RT-PCR and Northern hybridization.

RESULTS

Northern hybridization, RT-PCR and Western blot analysis revealed that mHa 1, 2, 3 and 4 keratins are expressed in the skin, but not in cornea, whereas the expression of K12 is limited to the corneas of the Bsk mice. These data ruled out the hypothesis that Bsk phenotype results from a recombination event between K12 and mHa 1, 2, 3 and 4. Ultrastructural and biochemical analyses also indicated that Bsk does not involve negative dominant mutations of keratin 12, mHa 1, 2, 3 and 4, epidermal-specific keratin 10, or basal cell-specific keratin 14. Expression of an acidic 50 kD keratin, recognized by monoclonal antibody AK 2, was up-regulated in the injured corneas of normal mice as well as Bsk corneas.

CONCLUSION

The gene linked to the Bsk mutation remains unknown. The pathological changes in the skin and corneas may be secondary to the loss of protecting hairs and lashes by an unknown mechanism.

Characterization and expression of the mouse lumican gene

Lumican is one of the major keratan sulfate proteoglycans (KSPG) in vertebrate corneas. We previously cloned the murine lumican cDNA. This study determines the structure of murine lumican gene (Lum) and its expression during mouse embryonic developments. The mouse lumican gene was isolated from a bacterial artificial chromosome mouse genomic DNA library and characterized by polymerase chain reaction and Southern hybridization. The lumican gene spans 6.9 kilobase pairs of mouse genome. The gene consists of three exons and two introns. Exon 1 constitutes 88 bases (b) of untranslated sequence. Exon 2 is 883 b and contains most of the coding sequence of lumican mRNA, and exon 3 has 152 b of coding sequence and 659 b of 3' noncoding sequence. The mouse lumican gene has a TATCA element, a presumptive TATA box, which locates 27 b 5'-upstream from the transcription initiation site. Northern hybridization and in situ hybridization indicate that in early stages of embryonic development, day 7 post coitus the embryo expresses little or no lumican. Thereafter, different levels of lumican mRNA can be detected in various organ systems, such as cornea stroma, dermis, cartilage, heart, lung, and kidney. The cornea and heart are the two tissues that have the highest expression in adult. Immunoblotting studies found that KSPG core proteins became abundant in the cornea and sclera by postnatal day 10 but that sulfated KSPG could not be detected until after the eyes open. These results indicate that lumican is widely distributed in most interstitial connective tissues. The modification of lumican with keratan sulfates in cornea is concurrent with eye opening and may contribute to corneal transparency.

The role of IFN regulatory factor-1 in synovitis and nitric oxide production

The IFN regulatory factor-1 (IRF-1) DNA binding protein regulates expression of genes that are involved with the induction of immune and inflammatory responses. The present study used mice with a targeted disruption of the IFN regulatory factor-1 gene (IRF-1-/-) to examine the role of this transcription factor in synovial inflammation and nitric oxide production. Intraarticular injection of IL-1 or LPS was associated with a significantly reduced intensity of synovial lining hyperplasia and leukocyte infiltration in the IRF-1-/- mice as compared with wild-type mice of the same parental lineage C57BL/6. Nitric oxide (NO) is involved with the pathogenesis of arthritis, and IRF-1 regulates expression of inducible NO synthase (iNOS) in mononuclear phagocytes. Articular chondrocytes from IRF-1-/- mice produced similar levels of NO in response to IL-1 or LPS. Furthermore, the synergistic induction of NO by IFN-gamma and IL-1 or LPS was almost identical in chondrocytes from wild-type and IRF-1-/- mice. This was in contrast to the expected decrease in NO production by peritoneal macrophages from IRF-1-/- mice, suggesting that IRF-1 is not required for iNOS expression in chondrocytes. These results indicate that IRF-1 has a tissue-specific role in the induction of iNOS. Inhibition of this transcription factor may represent a novel approach in controlling inflammatory diseases such as arthritis.

Synthetic studies of vitamin D analogs. XXIV. Synthesis of active vitamin D3 analogs substituted at the 2 beta-position and their preventive effects on bone mineral loss in ovariectomized rats

Analogs related to 1 alpha,25-dihydroxy-2 beta-(3-hydroxypropoxy)vitamin D3 (ED-71) (4), oxa-type and carba-type analogs of vitamin D3 bearing substituents at the 2 beta-position of 1 alpha,25-dihydroxyvitamin D3 (1), were synthesized from the alpha-epoxides (6 and 13). Three analogs, ED-71 (4) and two carba-type analogs (16 and 26), showed potent preventive effects on bone mineral loss in pre-osteoporosis model rats. ED-71 (4) was concluded to be an optimized analog and a promising candidate for the treatment of osteoporosis.

The role of IFN regulatory factor-1 in synovitis and nitric oxide production

The IFN regulatory factor-1 (IRF-1) DNA binding protein regulates expression of genes that are involved with the induction of immune and inflammatory responses. The present study used mice with a targeted disruption of the IFN regulatory factor-1 gene (IRF-1-/-) to examine the role of this transcription factor in synovial inflammation and nitric oxide production. Intraarticular injection of IL-1 or LPS was associated with a significantly reduced intensity of synovial lining hyperplasia and leukocyte infiltration in the IRF-1-/- mice as compared with wild-type mice of the same parental lineage C57BL/6. Nitric oxide (NO) is involved with the pathogenesis of arthritis, and IRF-1 regulates expression of inducible NO synthase (iNOS) in mononuclear phagocytes. Articular chondrocytes from IRF-1-/- mice produced similar levels of NO in response to IL-1 or LPS. Furthermore, the synergistic induction of NO by IFN-gamma and IL-1 or LPS was almost identical in chondrocytes from wild-type and IRF-1-/- mice. This was in contrast to the expected decrease in NO production by peritoneal macrophages from IRF-1-/- mice, suggesting that IRF-1 is not required for iNOS expression in chondrocytes. These results indicate that IRF-1 has a tissue-specific role in the induction of iNOS. Inhibition of this transcription factor may represent a novel approach in controlling inflammatory diseases such as arthritis.

High incidence of nitrosamine-induced tumorigenesis in mice lacking DNA repair methyltransferase

The enzyme O6-methylguanine-DNA methyltransferase repairs alkylation-induced DNA damage, O6-methylguanine and O4-methylthymine, the former being formed more frequently. Previously, by means of gene targeting, we generated mice in which alleles for methyltransferase were disrupted. We now use these mouse lines, which are totally deficient in methyltransferase activity, to examine protective effects of the enzyme against tumor formation. In gene-targeted female mice given an i.p. injection of 5 mg/kg of dimethylnitrosamine, a larger number of liver and lung tumors occurred, as compared with normal female mice treated in the same manner. In male mice given a lower dose of carcinogen, the difference between normal and gene-targeted mice was statistically insignificant although more tumors did form in the gene-targeted mice. Methyltransferase apparently afforded protection from nitrosamine-induced tumorigenesis.

Methylnitrosourea-induced tumorigenesis in MGMT gene knockout mice

Gene targeting was used to obtain mice defective in the MGMT gene, encoding O6-methylguanine-DNA methyltransferase [Tsuzuki et al., Carcinogenesis (Lond.), 17: 1215-1220, 1996]. These MGMT-/- mice were most sensitive to the alkylating carcinogen, methylnitrosourea; when varied doses of methylnitrosourea were administered to 6-week-old mice and survivals at the 30th day were determined, LD50s of MGMT-/- and MGMT+/+ mice were 20 and 240 mg/kg of body weight, respectively. MGMT+/- mice were as resistant as MGMT+/+ mice, but some difference in survival time was noted when the two genotypes of mice were exposed to a relatively high dose of methylnitrosourea. A large number of thymic lymphomas, as well as lung adenomas, occurred in MGMT-/- mice exposed to methylnitrosourea at a dose of 2.5 mg/kg of body weight. In case of exposure to the same dose of drug, no or few tumors occurred in the MGMT+/+ and MGMT+/- mice. It appears that the DNA repair methyltransferase protein protected these mice from methylnitrosourea-induced tumorigenesis.

Alkylation-induced apoptosis of embryonic stem cells in which the gene for DNA-repair, methyltransferase, had been disrupted by gene targeting

An enzyme O6-methylguanine-DNA methyltransferase (MGMT) catalyzes transfer of a methyl group from O6-methylguanine and O4-methylthymine of alkylated DNA to its own molecule, thereby repairing the pre-mutagenic lesions in a single step reaction. Making use of gene targeting, we developed mouse embryonic stem (ES) cell lines deficient in the methyltransferase. Quantitative immunoblot analysis and enzyme assay revealed that MGMT-/- cells, in which both alleles were disrupted, contained no methyltransferase protein while cells with one intact allele (MGMT+/-) contained about half the amount of protein carried by the parental MGMT+/+ cells. MGMT-/- cells have an extremely high degree of sensitivity to simple alkylating agents, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-methyl-N-nitrosourea (MNU), whereas MGMT+/- cells are slightly more sensitive to these agents, as compared with findings from normal cells. A high frequency of mutation was induced in MGMT-/- cells on exposure to a relatively low dose of MNNG. Electrophoretic analyses of the DNAs as well as fluorochrome staining of the cells revealed that MGMT-/- cells treated with MNNG undergo apoptotic death, which occurs after G2-M arrest in the second cycle of cell proliferation.

Keratin 12-deficient mice have fragile corneal epithelia

PURPOSE

Expression of the K3-K12 keratin pair characterizes the corneal epithelial differentiation. To elucidate the role of keratin 12 in the maintenance of corneal epithelium integrity, the authors bred mice deficient in keratin 12 by gene-targeting techniques.

METHODS

One allele of murine Krt1.12 gene was ablated in the embryonic stem cell line, E14.1, by homologous recombination with a DNA construct in which the DNA element between intron 2 and exon 8 of the keratin 12 gene was replaced by a neo-gene. The homologous recombinant embryonic stem cells were injected to mouse blastocysts, and germ lines of chimeras were obtained. The corneas of heterozygous and homozygous mice were characterized by clinical observations using stereomicroscopy, histology with light and electron microscopy, Western immunoblot analysis, immunohistochemistry, in situ hybridization, and Northern hybridization.

RESULTS

The heterozygous mice (+/-) one allele of the Krt1.12 gene appear normal and do not develop any clinical manifestations (e.g., corneal epithelial defects). Homozygous mice (-/-) develop normally and suffer mild corneal epithelial erosion. Their corneal epithelia are fragile and can be removed by gentle rubbing of the eyes or brushing with a Microsponge. The corneal epithelium of the homozygote (-/-) does not express keratin 12 as judged by immunohistochemistry, Western immunoblot analysis with epitope-specific anti-keratin 12 antibodies, Northern hybridization with 32P-labeled keratin 12 cDNA, and in situ hybridization with an anti-sense keratin 12 riboprobe. Light and electron microscopy revealed subtle abnormalities in the corneal epithelia of -/- mice (i.e., a decrease in number of cell layers) and cytolysis of superficial cells, but the number of hemidesmosomes and desmosomes are normal in basal and suprabasal cells. The number of keratin intermediate filaments in basal and suprabasal corneal epithelial cells in -/- mice decreases, and they appear as dense bundles. This morphology is similar to that of keratin intermediate filaments in epidermal epithelial, cells but differs from that of normal corneal epithelial cells in which the keratins form fine filamentous networks. The superficial epithelial cells are devoid of keratin intermediate filaments and often detach from the corneal surface of -/- mice.

CONCLUSIONS

The presence of cornea-specific K3-K12 keratin pairs is essential for the maintenance of corneal epithelium integrity.

Organization and expression of the mouse gene for DNA repair methyltransferase

06-Methylguanine-DNA methyltransferase (MGMT) is present in various organisms, from bacteria to human cells, and plays an important role in preventing mutations caused by alkylating substances. To understand better the regulatory mechanism involved in the expression of the gene and to construct a mouse model to investigate roles of the enzyme in carcinogenesis, the genomic sequence for mouse methyltransferase was isolated and characterized. The gene consists of 5 exons and spans over 180 kb, whereas mRNA for the enzyme was less than 1 kb. The promoter region for the gene is GC-rich, contains many Sp1 recognition sequences and lacks typical TATA and CCAAT boxes. Primer extension and S1 mapping revealed the existence of multiple transcription initiation sites, among which a major site was defined as +1. The putative promoter region was placed upstream of the chloramphenicol acetyltransferase (CAT) reporter gene and the construct was introduced into mouse NIH-3T3 cells. Deletion analyses revealed that a sequence from -262 to + 56 carries the basic promoter activity. In addition, an adjacent region, spanning from +56 to +95, carries an E2F-like element that greatly stimulates the frequency of transcription. Alteration of TTTTGGGGC to TTAACGGGC considerably reduced the activity.

Mini ecosystem in space--preliminary experiment on board STS-77

An enclosed ecosystem which is stable on Earth will behave differently when brought into space. Micro-gravity and radiation will affect the dynamics of material circulation or the activities of small creatures of the ecosystem. One series of space experiments aiming to address such issues was planned in the United States (It is termed as ABS--Autonomous Biological System) and Japanese group has been involved with cooperating with the analysis of the flight samples. Before the ecosystem will be on board Russian Space Station "Mir" later 1996 for 3 months, a preliminary flight was carried out in May 1996 on Space Shuttle (STS-77) for 10 days flight. It was the first of such experiments to fly one whole ecosystem in space.

Targeted disruption of the DNA repair methyltransferase gene renders mice hypersensitive to alkylating agent

Alkylation of DNA at the O(6)-position of guanine is one of the most critical events leading to induction of mutation as well as to cancer. The enzyme O(6)-methylguanine-DNA methyltransferase repairs this and related lesions in DNA. By means of gene targeting, we established mouse lines deficient in the methyltransferase gene and tissues from these mice contained no methyltransferase activity. Administration of methylnitrosourea to these gene-targeted mice led to early death, and normal mice treated in the same manner showed no untoward effects. In mice given methylnitrosourea treatment, the bone marrow became hypocellular and there was a drastic decrease in the number of leukocytes and platelets, thereby indicating an impaired reproductive capacity of hematopoietic stem cells. Methyltransferase apparently protected these mice from the pancytopenia caused by the alkylating agent.

TGF-beta contributes to the shift toward Th2-type responses through direct and IL-10-mediated pathways in tumor-bearing mice

In previous reports, we showed that tumor-derived TGF-beta induced overproduction of IL-10, and these suppressive cytokines caused macrophage suppression in EL4-bearing mice. Proliferation of T cells from EL-4, but not IL-2, whereas T cells from normal mice were responsive to IL-2. A balance between Th1- and Th2-type cytokine production in EL4-T in response to anti-CD3 Ab or phorbor myristate acetate plus A23187 shifted toward the Th2 dominant pattern. The prevention of TGF-beta and IL-10 activates in vivo by administration of anti-IL-10 Ab (anti-IL-10) or anti TGF-beta Ab (anti-TGF-beta) resulted in the reduction in EL4-T of both IL-4 dependent proliferation and Th2-dominant cytokine production induced by anti-CD-3 stimulation. In addition, the anti-TGF-beta treatment resulted in complete restoration in EL4-T of suppressed IL-2 responsiveness, IL-2R expression, and Th1-type cytokine production, whereas the anti-IL-10 treatment produced partial recovery. These results lead us to conclude that TGF-beta drives the shift in the Th1/Th2 balance toward Th2 via IL-10-mediated development of the Th2 responses and via inhibition of the Th1-type responses directly in EL4-bearing mice.

TGF-beta contributes to the shift toward Th2-type responses through direct and IL-10-mediated pathways in tumor-bearing mice

In previous reports, we showed that tumor-derived TGF-beta induced overproduction of IL-10, and these suppressive cytokines caused macrophage suppression in EL4-bearing mice. Proliferation of T cells from EL-4, but not IL-2, whereas T cells from normal mice were responsive to IL-2. A balance between Th1- and Th2-type cytokine production in EL4-T in response to anti-CD3 Ab or phorbor myristate acetate plus A23187 shifted toward the Th2 dominant pattern. The prevention of TGF-beta and IL-10 activates in vivo by administration of anti-IL-10 Ab (anti-IL-10) or anti TGF-beta Ab (anti-TGF-beta) resulted in the reduction in EL4-T of both IL-4 dependent proliferation and Th2-dominant cytokine production induced by anti-CD-3 stimulation. In addition, the anti-TGF-beta treatment resulted in complete restoration in EL4-T of suppressed IL-2 responsiveness, IL-2R expression, and Th1-type cytokine production, whereas the anti-IL-10 treatment produced partial recovery. These results lead us to conclude that TGF-beta drives the shift in the Th1/Th2 balance toward Th2 via IL-10-mediated development of the Th2 responses and via inhibition of the Th1-type responses directly in EL4-bearing mice.

Cytotoxicity tests for antimicrobial agents using cultured skin substitutes fixed at interface of air and culture medium

The present study is focused on a new cytotoxicity test using cultured dermal and epidermal sheets, which are fixed at the air and medium interface as a wound surface model. The cultured dermal sheet is composed of human fibroblasts and a collagen matrix, and the cultured epidermal sheet is composed of human keratinocytes and a collagen matrix. Each cultured sheet was fixed at the air and medium interface, over which a piece of test specimen was placed. The in vitro system created, provides a mimetic wound surface since during wound repair, fibroblasts are embedded in an extracellular matrix, while keratinocytes migrate and proliferate on provisional granulation tissue. The results thus obtained in this cytotoxicity test are useful for determining the efficacious amount of antimicrobial agent used in clinical cases.

Leustroduscin B, a new cytokine inducer derived from an actinomycetes, induces thrombocytosis in mice

Leustroduscin B (LSN-B), a novel colony-stimulating factor (CSF) inducer produced by an actinomycetes, has previously been shown to induce CSF production in bone marrow stromal cells. To determine the biological activity of LSN-B on hematopoiesis in vivo, LSN-B was administered intraperitoneally to mice every day for three to six days. Peripheral platelet counts were markedly elevated on days 4 through 6 compared with the control mice injected with vehicle. Serum II/6 levels were low (0.8 ng/ml) or virtually undetectable in the drug treated groups. This cytokine profile suggests that LSN-B induction of thrombocytosis is mechanistically distinct from other cytokine inducers such as IL-1 or FK-565.

TGF-beta enhances macrophage ability to produce IL-10 in normal and tumor-bearing mice

In the present study, we demonstrate that TGF-beta is capable of enhancing macrophage ability to produce IL-10 in normal and EL4 tumor-bearing mice. We found the increase in IL-10 in ascitic fluid and IL-10 mRNA expression in macrophages in parallel with the TGF-beta level and tumor progression. The macrophage production of IL-10 in the tumor-bearing mice was significantly enhanced without LPS stimulation in vitro, compared with normal controls. To clarify the mechanism wherein increased IL-10 production was induced, anti-TGF-beta or anti-IL-10 Abs were administered to EL4-bearing mice. Administration of anti-TGF-beta Ab led to a reduction in the IL-10 contents in ascitic fluid of tumor-bearing mice; however, anti-IL-10 Ab administration did not prevent the increase in TGF-beta contents. Enhanced IL-10 production and mRNA expression of macrophages from the tumor-bearing mice were also reduced by anti-TGF-beta Ab administration. Both anti-TGF-beta and anti-IL-10 Ab administration restored the TNF-alpha production by macrophages in EL4-bearing mice. In normal macrophages, in vitro pretreatment with TGF-beta 1 potentiated IL-10 production, and when natural TGF-beta 1 was administered to normal mice, the recovered peritoneal macrophages showed enhanced IL-10 production. Based on the above findings it can be concluded that TGF-beta enhances macrophage ability to produce IL-10, which sheds a new light on the role of TGF-beta in the immune system.

TGF-beta enhances macrophage ability to produce IL-10 in normal and tumor-bearing mice

In the present study, we demonstrate that TGF-beta is capable of enhancing macrophage ability to produce IL-10 in normal and EL4 tumor-bearing mice. We found the increase in IL-10 in ascitic fluid and IL-10 mRNA expression in macrophages in parallel with the TGF-beta level and tumor progression. The macrophage production of IL-10 in the tumor-bearing mice was significantly enhanced without LPS stimulation in vitro, compared with normal controls. To clarify the mechanism wherein increased IL-10 production was induced, anti-TGF-beta or anti-IL-10 Abs were administered to EL4-bearing mice. Administration of anti-TGF-beta Ab led to a reduction in the IL-10 contents in ascitic fluid of tumor-bearing mice; however, anti-IL-10 Ab administration did not prevent the increase in TGF-beta contents. Enhanced IL-10 production and mRNA expression of macrophages from the tumor-bearing mice were also reduced by anti-TGF-beta Ab administration. Both anti-TGF-beta and anti-IL-10 Ab administration restored the TNF-alpha production by macrophages in EL4-bearing mice. In normal macrophages, in vitro pretreatment with TGF-beta 1 potentiated IL-10 production, and when natural TGF-beta 1 was administered to normal mice, the recovered peritoneal macrophages showed enhanced IL-10 production. Based on the above findings it can be concluded that TGF-beta enhances macrophage ability to produce IL-10, which sheds a new light on the role of TGF-beta in the immune system.

Intracellular activation and cytotoxic action of RS-1541 against cultured human tumor cells

RS-1541, an acyl-derivative of rhizoxin (Fig. 1), is a potent antitumor compound. This agent showed cytotoxicity in vitro on some cultured human tumor cells, although it was less potent than rhizoxin. Rhizoxin exhibited antitumor effects by inhibiting the polymerization of tubulin, whereas RS-1541 did not inhibit tubulin polymerization in vitro. However, cell cycle analysis in vivo showed that the two agents had the same mode of action. The cytotoxicity of RS-1541 was enhanced when the initial cell density of the cells was increased. The cytotoxicity was also enhanced when the membrane fraction of St-4 cells, which were the most sensitive to RS-1541 among the cell lines tested, was added to the target cells. When St-4 cells were incubated with [14C]-RS-1541, significant amounts of [14C]-rhizoxin were produced within the cells. Further fractionation of the crude membrane showed that the activity that enhanced the cytotoxicity of RS-1541 (RS-1541-enhancing activity) belonged to the mitochondrial-lysosomal fraction, not to the microsomal fraction. Both the enhancing activity and the activity that converting [14C]-RS-1541 to [14C]-rhizoxin (RS-1541-converting activity) were inhibited by treatment with chloroquine, an inhibitor of lysosomal function. Cholesterol esterase derived from Candida cylindracea had RS-1541-enhancing and -converting activities. These data suggest that RS-1541 exerts its cytotoxic action after being converted to rhizoxin within the cells by a lysosomal enzyme such as cholesterol esterase.

Delivery and cytotoxicity of RS-1541 in St-4 human gastric cancer cells in vitro by the low-density-lipoprotein pathway

RS-1541 is a 13-O-palmitoyl derivative of rhizoxin, an inhibitor of tubulin polymerization. RS-1541 has been shown to bind preferentially to plasma lipoproteins and to exhibit selective and sustained uptake by tumors in mice. To elucidate a mechanism of RS-1541 cytotoxicity, the cellular uptake and the cytotoxicity of a complex of RS-1541 with human low-density lipoprotein (RS-1541/LDL complex) were investigated in cultured St-4 human gastric cancer cells. Both the cellular uptake and the cytotoxicity of the RS-1541/LDL complex were greater in cells with higher LDL-receptor activities than in control cells. Excess amounts of LDL or 1 microM of monensin, a proton ionophore, significantly inhibited both the uptake and the cytotoxicity of the complex. Chloroquine, an inhibitor of lysosomal enzymes, decreased the intracellular level of rhizoxin liberated from RS-1541 and suppressed the cytotoxicity of the RS-1541/LDL complex. However, a detergent-aided solution of RS-1541 showed very low cellular uptake and cytotoxicity, irrespective of the LDL-receptor activities of these cells. These results demonstrate that the RS-1541/LDL complex is incorporated into the cells via the LDL receptor and that it manifests its cytotoxic activity after forming rhizoxin, the original antitumor agent, in the lysosomes.

Improvement of macrophage dysfunction by administration of anti-transforming growth factor-beta antibody in EL4-bearing hosts

An experimental therapy for improvement of macrophage dysfunction caused by transforming growth factor-beta (TGF-beta) was tried in EL4 tumor-bearing mice. TGF-beta was detected in cell-free ascitic fluid from EL4-bearers, but not in that from normal mice, by western blot analysis. The ascites also showed growth-suppressive activity against Mv1Lu cells, and the suppressive activity was potentiated by transient acidification. To investigate whether the functions of peritoneal macrophages were suppressed in EL4-bearers, the abilities to produce nitric oxide and tumor necrosis factor-alpha (TNF-alpha) upon lipopolysaccharide (LPS) stimulation were measured. Both abilities of macrophages in EL4-bearing mice were suppressed remarkably on day 9, and decreased further by day 14, compared with non-tumor-bearing controls. TGF-beta activity was abrogated by administration of anti-TGF-beta antibody to EL4-bearing mice. While a large amount of TGF-beta was detected in ascitic fluid from control EL4-bearers, little TGF-beta was detectable in ascites from EL4-bearers given anti-TGF-beta antibody. Furthermore, while control macrophages exhibited little or no production of nitric oxide and TNF-alpha on LPS stimulation in vitro, macrophages from EL4-bearers administered with anti-TGF-beta antibody showed the same ability as normal macrophages. These results clearly indicate that TGF-beta contributes to macrophage dysfunction and that the administration of specific antibody for TGF-beta reverses macrophage dysfunction in EL4-bearing hosts.

Augmentation of host resistance against bacterial infection by treatment with leustroducsin B, a new CSF inducer

We tested the in vivo activity of leustroducsin B (LSN B), a new colony-stimulating factor (CSF) inducer isolated from the culture broth of Streptomyces platensis, with mice infected with Escherichia coli. Treatment with LSN B augmented the host resistance to lethal infection of E. coli at doses between 0.1 mg/kg and 1 mg/kg. Serum interleukin-6 (IL-6) levels were found to increase after this treatment, and superoxide anion generation of neutrophils was enhanced in vivo, suggesting that LSN B augmented the host resistance at least in part by inducing IL-6, which subsequently enhanced the bactericidal activity of the neutrophils.

Development of a new wound dressing with antimicrobial delivery capability

A bilaminar wound dressing composed of an outer membrane and an inner three-dimensional matrix of a fabric or a sponge may be considered to constitute an ideal structure that promotes wound healing: the outer membrane prevents body fluid loss, controls water evaporation, and protects the wound surface from bacterial invasion, and the inner matrix encourages adherence by tissue growth into the matrix. Using this concept, we developed a biosynthetic wound dressing with a drug delivery capability. This medicated wound dressing is composed of a spongy sheet of a chitosane derivative and collagen mixture that is laminated to an antimicrobial-impregnated polyurethane membrane. In this study, a gentamycin sulfate-impregnated wound dressing was prepared and evaluated. The antimicrobial efficacy of this wound dressing was examined on an agar plate seeded with Pseudomonas aeruginosa. Also, the cytotoxicity of an antimicrobial released from this wound dressing was examined in an in vitro system with cultured skin substitutes. Both in vitro tests have shown that this wound dressing is capable of suppressing bacterial growth and minimizing cellular damage. In addition, in the treatment of wounds inflicted on rats and rabbits, this wound dressing was shown to be efficacious in covering full-thickness and split-thickness skin defects. Finally, the efficacy of this wound dressing was evaluated in a nonrandomized open-label study of 31 clinical cases. In 31 cases treated with this wound dressing, good or excellent wound healing was achieved.

Using a computer color-matching system in color reproduction of porcelain restorations. Part 3: A newly developed spectrophotometer designed for clinical application

This paper reports the development of a newly modified, noncontact spectrophotometer for clinical use. The instrument is capable of accurately measuring the color within small areas (1 x 2 mm) of a tooth. This spectrophotometer used a 45 degree/0 degree geometry, a 150W halogen lamp, and fiberoptics to focus the light, together with a lens having a focal point distance of 85 mm. A movable platform was added to the apparatus to automatically scan and measure the color of specific areas. Short-term repeatability indicated the color difference delta E to be approximately 0.15.

Behavior of Japanese tree frogs under microgravity on MIR and in parabolic flight

Japanese tree frogs (Hyla japonica) were flown to the space station MIR and spent eight days in orbit during December, 1990. Under microgravity, their postures and behaviors were observed and recorded. On the MIR, floating frogs stretched four legs out, bent their bodies backward and expanded their abdomens. Frogs on a surface often bent their neck backward and walked backwards. This behavior was observed on parabolic flights and resembles the retching behavior of sick frogs on land--a possible indicator of motion sickness. Observations on MIR were carried out twice to investigate the frog's adaptation to space. The frequency of failure in landing after a jump decreased in the second observation period. After the frogs returned to earth, readaptation processes were observed. The frogs behaved normally as early as 2.5 hours after landing.

Activation of temperature-dependent flagellar movement of demembranated fowl spermatozoa: involvement of an endogenous serine protease

In the presence of ATP, the motility of demembranated fowl spermatozoa was vigorous at 30 degrees C, but negligible at 40 degrees C. Motility could be restored at 40 degrees C by the addition of 10-100 ng trypsin ml-1. Chymotrypsin also stimulated the motility, but neither papain nor carboxypeptidase B appreciably affected motility. Conversely, at 30 degrees C sperm motility was inhibited by aprotinin or phenylmethylsulfonyl fluoride. These results suggest that endogenous protease, presumably serine protease, activity is instrumental in the regulation of fowl sperm motility. It seems likely that the site of action of this protease is axonemal, but a direct effect of added protease on dynein ATPase activity could not be demonstrated.

Novel microbial metabolites of the phoslactomycins family induce production of colony-stimulating factors by bone marrow stromal cells. II. Isolation, physico-chemical properties and structure determination

Leustroducsins (LSNs) A, B and C, novel inducers of colony-stimulating factors (CSFs), were isolated from culture broth of Streptomyces platensis SANK 60191 mainly by ethyl acetate extraction and preparative reverse-phase HPLC. The molecular weights and molecular formulae of LSNs A, B and C are 641: C32H52O10NP, 669: C34H56O10NP and 669: C34H56O10NP, respectively. The structure elucidation revealed that they belong to the phoslactomycin group antibiotics, and their structures contain an alpha,beta-unsaturated delta-lactone, an amino group, a phosphate ester and a cyclohexane ring moiety. The structures differ only at the substituent bound to the cyclohexane ring.

A cultured skin substitute composed of fibroblasts and keratinocytes with a collagen matrix: preliminary results of clinical trials

The cultured skin substitute was created through successive cultivation of fibroblasts and keratinocytes that were combined within a collagen matrix. This collagen matrix was composed of a collagen spongy sheet and a collagen gel. The collagen spongy sheet was designed to produce a honeycomb structure having many holes in which all holes through the sheet were filled with collagen gel. This specific structure thereby allows for the nourishment of the cultured keratinocytes on the surface of the matrix when placed on the graft bed. In this study, autologous cultured skin substitute was applied to a 51-year-old man who had sustained a burn injury. Three sheets of the cultured skin substitute (6 x 9.5 cm) were grafted onto the full-thickness excised wound in the right anterior chest wall. One week after grafting most of the matrix disappeared and stratified keratinocytes were seen to have firmly attached to the underlying tissue. Five weeks after grafting a cornified epidermal layer was seen. Ten months after grafting a mature epidermis and a well-differentiated papillary and reticular dermis replacement were observed. The physical properties and color of this grafted area resemble those of normal skin. In the second test case, autologous cultured skin substitute was applied to a 30-year-old man with a scar remaining after tattoo removal. Eight sheets of the cultured skin substitute (10 x 18 cm) were applied on an excised wound (thickness, 0.02-0.025 in.) of both the fore- and upper arms. The histological appearance of a biopsied skin specimen from the grafted area at 3 months after grafting showed a mature epidermis and a well-differentiated reticular dermis replacement. The regenerated skin at 14 months after grafting showed an excellent result.