Pepstatin A-sensitive aspartic proteases in lysosome are involved in degradation of the invariant chain and antigen-processing in antigen presenting cells of mice infected with Leishmania major

We previously reported that CA074, a specific inhibitor of cathepsin B, significantly deviated immune responses from the disease-promoting Th2 type to the protective Th1 type in BALB/c mice infected with Leishmania major. Herein, we found that pepstatin A-sensitive aspartic proteases (PSAP) in lysosomes seem to play a different role from that of cathepsin B in antigen-processing and Ii-degradation. That is, cathepsin B appears to digest 16-, 28-, and 31-kDa peptides of soluble leishmania antigen (SLA), whereas PSAP seems to process mainly 28-kDa peptides. Furthermore, the latter protease contributed to the degradation of Ii but cathepsin B did not. Following treatment with pepstatin A, both Th1 and Th2 responses were profoundly suppressed in resistant DBA/2 mice (H-2(d)) and in susceptible BALB/c mice (H-2(d)), and both strains of mice became markedly susceptible compared with the untreated groups, probably owing to failure in degradation of Ii and partly to failure in digestion of 28-kDa peptide.

CD4(+) v(alpha)14 NKT cells play a crucial role in an early stage of protective immunity against infection with Leishmania major

The roles of gamma delta T, NK and NKT cells in an early stage of protective immunity against infection with Leishmania major were investigated. Further, the contribution of these innate cells to the expression of 65 kDa heat shock protein (HSP65) in host macrophages was examined, since we found previously that this expression prevents apoptotic death of infected macrophages and is a crucial step in the acquisition of protective immunity against infection with various obligate intracellular protozoa including L. major. C57BL/6 and DBA/2 mice were found to be resistant against the infection on the basis of the parasite burden in their regional lymph nodes, and to strongly express HSP65 in their macrophages, whereas BALB/c mice were susceptible and barely expressed the HSP65. In those resistant mice, CD4(+) NKT cells prominently increased in their regional lymph node and were the main effector cells at least for an early stage of the protective immunity and for the HSP65 expression, whereas this subset did not increase in susceptible BALB/c mice. Further, neither gamma delta T nor NK cells in resistant mice contributed to those protective immune responses. The NKT cell subset bore CD3, CD4, TCR alpha beta, IL-2R beta and NK1.1 but scarcely asialo-GM(1). Moreover, this effector subset was confirmed to be V(alpha)14 NKT cells by using J(alpha)281(-/-) mice.

Evaluation of psychological effects due to bed rest

The psychological condition of astronauts is an important factor for ensuring mission success in limited space. Head-down tilting bed rest is a well-accepted method by which to simulate an acute stage of human adaptation to the weightless state in space flight. In our previous studies, the enhancement of depressive and neurotic levels occurred during a 20-day horizontal bed rest. In this study, we attempted to examine the depressive and neurotic levels, the mood status, and behavioral tendency of the subjects and to analyze the changes of 24-hour urinary excretion of 17-hydroxycorticosteroid-glucronides (17-OHCS) for an indicator of changes in the endocrine system due to physical and psychological stress during a 20-day 6-degrees head-down tilting bed rest (BR).

Immobilization on the day 14th does not disrupts the basic diurnal rhythm of bone resorption

Weight bearing and physical activity are important mechanical stimuli to bone growth and metabolism, and microgravity, such a space flight and/or bed rest, induces bone resorption and bone loss. An increased excretion of urinary Ca, an increased bone resorption and a decreased bone mineral density (BMD) have been observed in bed rest experiment of healthy subjects. Bone resorption markers show the specific circadian rhythms in human. Cross-linked carboxyl-terminal telopeptide of type I collagen (ICTP) and the urinary excretion of deoxypyridinoline (Dpy) are the highest in the early morning and the lowest late at night. Bed rest immobilization might influence these rhythms, due to no mechanical loading with loss of daily life activity. Bone resorption markers in healthy subjects had been compared between before and during bed rest to determine disruption of diurnal rhythms of bone resorption.

Inhibition of intracellular cathepsin activities and suppression of immune responses mediated by helper T lymphocyte type-2 by peroral or intraperitoneal administration of vitamin B6

We reported that pyridoxal phosphate (PAP), a coenzyme form of vitamin B6, strongly inhibits activities of cathepsin B and weakly inhibits those of cathepsins S, K, and C in vitro. Either intraperitoneal injection or peroral administration of medication doses of vitamin B6 in the diet caused dose-dependent inhibition of hepatic cathepsins B, L, S, and C, and the inhibition was exhibited much more significantly in the case of a high protein diet than in a low protein diet. Administration of vitamin B6 induced the suppression of immune responses against ovalbumin (OVA) mediated by helper T lymphocyte type-2, based on the suppression of antigen processing by cathepsin B inhibition, as in the case of CA-074 administration, a cathepsin B specific inhibitor. Ovalbumin-dependent production of immunoglobulins IgE, IgG1 and interleukin IL-4 was suppressed by administration of medication doses of pyridoxal (PA) or pyridoxine (PI), while the production of IgG2alpha and interferon (INF)-gamma mediated by helper T lymphocyte type 1 was not changed. Administration of medication doses of vitamin B6 caused the inhibition of intracellular cathepsin B activity due to suppression of the functions of helper T lymphocyte type-2.

Lysosomal cathepsin B plays an important role in antigen processing, while cathepsin D is involved in degradation of the invariant chain inovalbumin-immunized mice

We previously reported that CA074, a specific inhibitor of cathepsin B, modulates specific immune responses from the T helper 2 (Th2) type to Th1 type in BALB/c mice infected with Leishmania major. In the present study, we found that a similar type of immune deviation was also induced in mice immunized with ovalbumin (OVA). However, treatment of mice with pepstatin A, a specific cathepsin D inhibitor, suppressed the OVA-specific proliferation of lymphocytes and blocked the development of both Th1 and Th2 cellular responses. These inhibitors did not appear to have any direct influence in vitro on functions of naive lymphocytes. OVA antigen (47 000 MW) was digested mainly into 40 000 MW protein in vitro by lysosomal proteases from naive BALB/c mice, and its digestion was markedly inhibited by the addition of CA074, but not by addition of pepstatin A, during incubation. However, pepstatin A strongly suppressed the degradation of the major histocompatibility complex class II-associated invariant chain (Ii) molecule in vivo and in vitro. Thus, cathepsin B appears to process antigens directed to preferential activation of Th2 cells, while cathepsin D may be responsible for the degradation of Ii, the processing of which is essential in initiating the antigen-specific activation of Th1 and Th2 CD4+ T cells. These lysosomal proteases may have different functions in regulating immune responses.

Gene gun-mediated delivery of an interleukin-12 expression plasmid protects against infections with the intracellular protozoan parasites Leishmania major and Trypanosoma cruzi in mice

An interleukin-12 (IL-12) expression plasmid was transferred, using a gene gun, to mice infected with Leishmania major or Trypanosoma cruzi. Transfer of the IL-12 gene to susceptible BALB/c mice resulted in regression of lesion size and reduced the number of parasites in draining lymph nodes (LN) at the site of L. major infection. Coincident with these protective effects, the T-helper type (Th) response shifted towards Th1, as evaluated by cytokine production in vitro and L. major-specific antibody responses. Protective effects of the IL-12 gene were also observed in T. cruzi infection. Treatment of BALB/c mice infected with T. cruzi enhanced the production of interferon-gamma (IFN-gamma) by spleen cells, while suppressed production of interleukin-10 (IL-10) compared with control mice. Administration of anti-CD4 or anti-CD8 monoclonal antibody (mAb) abolished the protective immunity against T. cruzi infection, and treatment with the IL-12 gene could not restore the resistance in these mice. Mice depleted of natural killer (NK) cells with anti-asialo GM1 also became susceptible to infection, while the resistance was restored when these mice were treated with the IL-12 gene. Thus, target cells for the treatment appear to be CD4+ and CD8+ T cells, which are ordinarily activated by NK cells. These results suggest that the transfer of cytokine genes using a gene gun is an effective method for investigating the roles of cytokines and gene therapy in infectious diseases.

Expression and role of heat-shock protein 65 (HSP65) in macrophages during Trypanosoma cruzi infection: involvement of HSP65 in prevention of apoptosis of macrophages

The 65-kDa heat-shock protein (HSP65) is thought to play a role in host defense against infections with various microbial pathogens and in autoimmune inflammatory disorders. We investigated the biological function and expression mechanism of HSP65 in macrophages of mice infected with Trypanosoma cruzi. BALB/c mice, which are susceptible to T. cruzi, showed high levels of parasitemia, and 80% of these mice died within 42 days after the infection, whereas resistant C57BL/6 or DBA/2 mice showed low levels of transient parasitemia and all survived. HSP65 expression was correlated with resistance to T. cruzi infection; HSP65 was more strongly expressed in macrophages of resistant C57BL/6 and DBA/2 mice than in macrophages of susceptible BALB/c mice. Immunodeficient BALB/c-nu/nu (nude) and C.B-17 scid/scid (SCID) mice were shown to be highly susceptible to this infection, and they did not express detectable levels of HSP65, suggesting that T cells play essential roles in the expression of HSP65 as well as in protective immunity against the infection. CD4(+) T cells, but not CD8(+) T cells or gammadelta T cells, were the cell population responsible for the induction of HSP65 expression in macrophages. Furthermore, depletion of asialo GM-1(+) NK cells made resistant C57BL/6 mice more susceptible to the infection, and HSP65 expression in their macrophages was abolished. Semiquantitative reverse transcription PCR analyses showed that both interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) mRNA levels in CD4(+) T cells became low when resistant C57BL/6 mice were depleted of NK cells, suggesting that NK cells contribute to functional differentiation of CD4(+) T cells and thereby affect the induction of HSP65 expression. To determine the function of HSP65, macrophages were treated in vitro with antisense oligonucleotide for HSP65 prior to inducing HSP65 with IFN-gamma plus TNF-alpha or T. cruzi infection. This treatment did not affect the production of nitric oxide following activation, but the treated macrophages became susceptible to apoptosis. These results indicate that HSP65 plays a role in preventing the apoptosis of macrophages and thereby contributes to host resistance against T. cruzi infection.

[Adhesive and sealing effects of TO-193 on tissues and organs in various experimental models]

We studied the adhesive and sealing effects of sheet style fibrin adhesive, TO-193 (TachoComb), on some tissues and organs, comparing them with those of sheet style collagen agent, collagen sponge, Novacol, and Avitene and liquid fibrin adhesive agent, Beriplast P. TO-193 showed more a potent adhesive effect on liver than the sheet style collagen agents and was more potent on bone and skin than the liquid fibrin adhesive agent. Furthermore, TO-193 had a potent sealing effect at the site of incomplete suture immediately after application on a motile organ such as lung and stomach. These effects may be partly attributable to rapid expression of the effect due to the presence of a high concentration of fibrinogen on coverage. Enhancement of fibrin penetrability to the tissues by compression and inhibition of cleavage of coverage by the collagen sponge also may be participating in the effects of TO-193. These results suggest that TO-193 will be a valuable adhesive and sealing agent.

[Hemostatic effect of a novel sheeted fibrin adhesive agent, TO-193, on experimental incision models]

TO-193 (TachoComb) is a new fibrin adhesive agent that consists of a collagen sheet coated with fibrin glue. We compared the hemostatic effect of TO-193 in several experimental models with Beriplast P as a fibrin adhesive agent, Avitene and Novacol as a microfibrillar collagen hemostat, and a sponge-like collagen sheet as the constitutional parts of TO-193. In the in vitro bleeding model in which blood leaks out through cotton cloth, the pressure of TO-193 when blood leakage was observed was higher than those of Beriplast P, Avitene, Novacol and the collagen sheet, indicating that TO-193 possessed a strong adhesive effect on the bleeding surface. On the kidney resection surface, TO-193 showed a more potent adhesive effect than those of Beriplast P and the collagen sheet, suggesting that TO-193 has a potent hemostatic effect. In the liver resection, TO-193 significantly reduced the bleeding volume compared with that of Novacol in normal rats. Furthermore, the bleeding volume of TO-193 was about half that of Beriplast P and equivalent to that of Novacol even in anticoagulant-treated rats. From these data, it is expected that TO-193 would be a valuable hemostatic agent for clinical use since TO-193 possesses a potent adhesive ability on the bleeding resection surface and would certainly stop bleeding in both patients with normal coagulation and those with a low blood coagulation condition.

[Evaluation of restenosis after percutaneous transluminal coronary angioplasty using a Doppler index, the Tei index]

Cardiac function and restenosis were evaluated after percutaneous transluminal coronary angioplasty (PTCA) using a Doppler index (the Tei index). Thirty-eight patients, 31 men and 7 women (mean age 57 years) with ischemic heart disease were studied. The underlying heart diseases were angina pectoris without left ventricular asynergy in 16 patients and old myocardial infarction (OMI) with left ventricular asynergy in 22 . Ejection fraction was measured by M-mode echocardiography and deceleration time, and the interval between cessation and onset of the mitral inflow velocity (a), ejection time at aortic valve (b), and the Tei index [(a-b)/b] were measured by M-mode echocardiography performed before and 6 months after PTCA. The ejection fraction, deceleration time and Tei index showed no changes after PTCA in patients with angina pectoris with or without restenosis. In patients with OMI with restenosis, the Tei index increased slightly after PTCA, from 0.56 +/- 0.15 to 0.61 +/- 0.13. The deceleration time changed from 0.23 +/- 0.03 to 0.24 +/- 0.02 msec, and the ejection fraction from 0.46 +/- 0.11 to 0.51 +/- 0.17, neither significantly. However, in patients with OMI without restenosis (15 out of 22 patients), the Tei index significantly improved after PTCA, from 0.55 +/- 0.13 to 0.48 +/- 0.12 (p < 0.05). In patients with left ventricular asynergy due to old myocardial infarction, without restenosis, the Tei index significantly improved after PTCA. The Tei index is useful for evaluating restenosis after PTCA in patients with OMI.

DNA immunization with Plasmodium falciparum serine repeat antigen: regulation of humoral immune response by coinoculation of cytokine expression plasmid

We immunized mice with plasmid expressing the 47-kDa amino-terminal domain of the Plasmodium falciparum serine repeat antigen (SERA) using gene gun and investigated humoral immune response to SERA antigen. Significant SERA-specific IgG was observed in BALB/c mice after immunization three times with SERA expression plasmid. Furthermore, these levels were increased by the coinoculation of cytokine (IFN-gamma, IL-4, GM-CSF, or IL-12) expression plasmid. In respect to the SERA-specific Ig subclasses, coinoculation of IFN-gamma, GM-CSF, or IL-12 expression plasmid increased the levels of SERA-specific IgG2a, and these were much higher than that in mice immunized with SERA expression plasmid alone. In contrast to the SERA-specific IgG2a, coinoculation of any cytokine expression plasmid did not change the levels of SERA-specific IgG1. These results indicate that cytokine expression plasmid enhances and regulates humoral immune response elicited by SERA DNA immunization.

Clinical course of atopic dermatitis in Japanese patients

We conducted a questionnaire study of 117 patients, who had first consulted the Department of Dermatology Kumamoto University Hospital 20 or 30 years ago, regarding the clinical course of atopic dermatitis (AD). Forty-one patients responded to the questionnaire. Seventeen patients (41.4%) had recovered and 24 patients (58.6%) still had AD. The AD had resolved in 12 of 13 (92.2%) with mild disease severity, four of 18 (22.2%) with moderate severity and one of ten (10%) with severe disease. The outcome was significantly better in the mild group than in the moderate or severe group (chi2=15.5, P=0.0008/chi2=14.8, P=0.00012, respectively). The resolution of the disease was not correlated with the sex of patient, age at onset, period of disease or family history.

[A case of gastric cancer with multiple bone metastasis treated by nocturnal 5-fluorouracil infusion combined with pamidronate]

Nocturnal infusion of 5-fluorouracil (5-FU) combined with pamidronate was performed in a 62-year-old male gastric cancer patient with multiple bone metastasis. The patient was administered 500 mg of 5-FU five days a week continuously for 10 hours per day from 21 o'clock to 7 o'clock for 5 months. In addition to 5-FU, 45 mg of pamidronate was administered intravenously every two weeks. Remarkable sclerotic changes were shown during the treatment in the bone metastatic foci, and the range of motion was enlarged. Serum levels of CEA and CA19-9 were decreased to the normal levels. There were no serious side effects such as myelosuppression, diarrhea or palmo-plantar dermatitis. This combination therapy of nocturnal infusion of 5-FU with pamidronate was considered effective for gastric cancer in patients with multiple bone metastasis without serious side effects.

Switch of CD4+ T cell differentiation from Th2 to Th1 by treatment with cathepsin B inhibitor in experimental leishmaniasis

When activated, CD4+ T helper cells differentiate functionally into one of two subsets, Th1 or Th2. Before the Th differentiation, Ags must be processed into peptide epitopes and presented to CD4+ T cells in association with MHC class II molecules. However, the proteases responsible for this Ag processing have not been well defined. When BALB/c mice susceptible to infection with Leishmania major were treated with a specific inhibitor (CA074) of cathepsin B, a lysosomal cysteine protease that digests exogenous antigenic proteins, those mice acquired resistance against infection with L. major and showed the shift of immune responses from Th2 to Th1; that is, they produced specific IgG2a Ab and generated IFN-gamma in contrast to untreated and infected mice that produced IgG1 and IgE and generated IL-4. CA074 interfered with the digestion of L. major Ags with lysosomal enzymes in vivo as well as in vitro. However, this inhibitor did not show any direct influence on the growth of L. major and the functions of T cells stimulated with anti-CD3 Ab. These findings indicate that cathepsin B inhibitor could switch CD4+ T cell differentiation from Th2 to Th1, suggesting that the alteration in Ag processing modulates the polarity of Th differentiation.

Carbamazepine-induced sinus node dysfunction and atrioventricular block in elderly women

We report on four elderly women in whom carbamazepine was suspected of inducing sinus node dysfunction (3 patients) and atrioventricular block (1 patient). Patients were treated with carbamazepine, 200 to 600 mg a day, for trigeminal neuralgia (n = 3) or epilepsy (n = 1). After 1 to 16 months of carbamazepine therapy, these patients were admitted to our emergency room because of bradyarrhythmia. Their conduction disturbances on electrocardiographic monitoring disappeared immediately after the cessation of carbamazepine intake. Provocation tests were performed on three patients. Because of renal insufficiency, one patient could not undergo the provocation test. Her carbamazepine clearance was markedly decreased. Carbamazepine induced sinus arrest in two patients within 48 hours after intake, but did not induce atrioventricular block in the remaining patient. In two patients, computer simulation of carbamazepine pharmacokinetics was performed and disclosed a clear-cut relationship between the plasma concentration of carbamazepine and the frequency of sinus arrest. During the test, the maximum plasma carbamazepine concentration in these two patients did not exceed the therapeutic range. However, it did exceed the range in the one with a negative test. Our results suggest that careful monitoring of ECG and plasma drug concentration is required with carbamazepine therapy, especially in elderly women.

Heat shock protein 65 induced by gammadelta T cells prevents apoptosis of macrophages and contributes to host defense in mice infected with Toxoplasma gondii

We previously reported that gammadelta T cells mediate the expression of endogenous heat shock protein 65 (HSP65) in macrophages of mice with acquired resistance against infection with Toxoplasma gondii. We show here that HSP65 contributes to protective immunity by preventing apoptosis of infected macrophages. Macrophages of BALB/c mice, which readily acquired resistance to T. gondii infection with the low virulence Beverley strain, strongly expressed HSP65, and only a few of these macrophages underwent apoptosis. On the other hand, the BALB/c mice were susceptible to the infection with the high virulence RH strain of T. gondii; their macrophages did not express HSP65 and did undergo apoptosis. Mice depleted of gammadelta T cells using a mAb specific for TCR-gammadelta became highly susceptible to infection even with the Beverley strain. In these mice, HSP65 expression was markedly suppressed, and their infected macrophages died via apoptosis. Apoptosis was induced in cultured macrophages or macrophage cell lines after infection in vitro with the RH strain, whereas apoptosis was prevented when HSP65 was induced in these cells, before infection, by activation with IFN-gamma and TNF-alpha. However, apoptosis associated with infection by T. gondii RH strain was not prevented when HSP65 synthesis was inhibited by introducing an antisense oligonucleotide for this protein into the cells before activation with IFN-gamma plus TNF-alpha. Thus, HSP65 appears to contribute to immunity by preventing the apoptosis of infected macrophages, and the high virulence Toxoplasma appears to have mechanisms that allow these organisms to evade the host defense system by interfering with HSP65 expression.

Heat shock protein 65 induced by gammadelta T cells prevents apoptosis of macrophages and contributes to host defense in mice infected with Toxoplasma gondii

We previously reported that gammadelta T cells mediate the expression of endogenous heat shock protein 65 (HSP65) in macrophages of mice with acquired resistance against infection with Toxoplasma gondii. We show here that HSP65 contributes to protective immunity by preventing apoptosis of infected macrophages. Macrophages of BALB/c mice, which readily acquired resistance to T. gondii infection with the low virulence Beverley strain, strongly expressed HSP65, and only a few of these macrophages underwent apoptosis. On the other hand, the BALB/c mice were susceptible to the infection with the high virulence RH strain of T. gondii; their macrophages did not express HSP65 and did undergo apoptosis. Mice depleted of gammadelta T cells using a mAb specific for TCR-gammadelta became highly susceptible to infection even with the Beverley strain. In these mice, HSP65 expression was markedly suppressed, and their infected macrophages died via apoptosis. Apoptosis was induced in cultured macrophages or macrophage cell lines after infection in vitro with the RH strain, whereas apoptosis was prevented when HSP65 was induced in these cells, before infection, by activation with IFN-gamma and TNF-alpha. However, apoptosis associated with infection by T. gondii RH strain was not prevented when HSP65 synthesis was inhibited by introducing an antisense oligonucleotide for this protein into the cells before activation with IFN-gamma plus TNF-alpha. Thus, HSP65 appears to contribute to immunity by preventing the apoptosis of infected macrophages, and the high virulence Toxoplasma appears to have mechanisms that allow these organisms to evade the host defense system by interfering with HSP65 expression.