Amelioration of type 1 diabetes by recombinant fructose-1,6-bisphosphate aldolase and cystatin derived from Schistosoma japonicum in a murine model.

Infection with helminth parasites or the administration of their antigens can prevent or attenuate autoimmune diseases. To date, the specific molecules that prime the amelioration are only limited. In this study, recombinant Schistosoma japonicum cystatin (rSjcystatin) and fructose-1,6-bisphosphate aldolase (rSjFBPA) were administered to female NOD mice via intraperitoneal (i.p.) injection to characterize the immunological response by the recombinant proteins. We have shown that the administration of rSjcystatin or rSjFBPA significantly reduced the diabetes incidence and ameliorated the severity of type 1 diabetes mellitus (T1DM). Disease attenuation was associated with suppressed interferon-gamma (IFN-γ) production in autoreactive T cells and with a switch to the production of Th2 cytokines. Following rSjcystatin or rSjFBPA injection, regulatory T cells (Tregs) were remarkably increased, which was accompanied by increased expression of interleukin-10 (IL-10) and transforming growth factor beta (TGF-ß). Our study suggests that helminth-derived proteins may be useful in strategies to limit pathology by promoting the Th2 response and upregulating Tregs during the inflammatory tissue-damage process in T1DM.

Therapeutic effect of Schistosoma japonicum cystatin on bacterial sepsis in mice.

BACKGROUND: Sepsis is a life-threatening complication of an infection and remains one of the leading causes of mortality in surgical patients. Bacteremia induces excessive inflammatory responses that result in multiple organ damage. Chronic helminth infection and helminth-derived materials have been found to immunomodulate host immune system to reduce inflammation against some allergic or inflammatory diseases. Schistosoma japonicum cystatin (Sj-Cys) is a cysteine protease inhibitor that induces regulatory T-cells and a potential immunomodulatory. The effect of Sj-Cys on reducing sepsis inflammation and mortality was investigated. METHODS: Sepsis was induced in BALB/c mice using cecal ligation and puncture (CLP), followed by intraperitoneal injection of different doses (10, 25 or 50 µg) of recombinant Sj-Cys (rSj-Cys). The therapeutic effect of rSj-Cys on sepsis was evaluated by observing the survival rates of mice for 96 h after CLP and the pathological injury of liver, kidney and lung by measuring the levels of alanine transaminase (ALT), aspartate transaminase (AST), blood urea nitrogen (BUN) and creatinine (Cr) in sera and the tissue sections pathology, and the expression of MyD88 in liver, kidney and lung tissues. The immunological mechanism was investigated by examining pro-inflammatory cytokines (TNF-α, IL-6, IL-1ß) and IL-10 and TGF-ß1 in mice sera and in culture of macrophages stimulated by lipopolysaccharides (LPS). RESULTS: rSj-Cys treatment provided significant therapeutic effects on CLP-induced sepsis in mice demonstrated with increased survival rates, alleviated overall disease severity and tissue injury of liver, kidney and lung. The rSj-Cys conferred therapeutic efficacy was associated with upregualted IL-10 and TGF-ß1 cytokines and reduced pro-inflammatory cytokines TNF-α, IL-6, IL-1ß. MyD88 expression in liver, kidney and lung tissues of rSj-Cys-treated mice was reduced. In vitro assay with macrophages also showed that rSj-Cys inhibited the release of pro-inflammatory cytokines and mediator nitric oxide (NO) after being stimulated by lipopolysaccharide (LPS). CONCLUSIONS: The results suggest the anti-inflammatory potential of rSj-Cys as a promising therapeutic agent on sepsis. The immunological mechanism underlying its therapeutic effect may involve the downregulation of pro-inflammatory cytokines and upregulation of IL-10 and TGF-ß1 cytokines possibly via downregulation of the TLR adaptor-transducer MyD88 pathway. The findings suggest rSj-Cys is a potential therapeutic agent for sepsis and other inflammatory diseases.

A recombinant cystatin from Ascaris lumbricoides attenuates inflammation of DSS-induced colitis.

Helminthiasis may ameliorate inflammatory diseases, such as inflammatory bowel disease and asthma. Information about immunomodulators from Ascaris lumbricoides is scarce, but could be important considering the co-evolutionary relationships between helminths and humans. We evaluated the immunomodulatory effects of a recombinant cystatin from A. lumbricoides on an acute model of dextran sodium sulphate (DSS)-induced colitis in mice. From an A. lumbricoides cDNA library, we obtained a recombinant cystatin (rAl-CPI). Protease activity inhibition was demonstrated on cathepsin B and papain. Immunomodulatory effects were evaluated at two intraperitoneal doses (0.5 and 0.25 µg/G) on mice with DSS-induced colitis. Body weight, colon length, Disease Activity Index (DAI), histological inflammation score, myeloperoxidase (MPO) activity, gene expression of cytokines and cytokines levels in colon tissue were analysed. Treatment with rAl-CPI significantly reduced DAI, MPO activity and inflammation score without toxic effects. Also, IL-10 and TGF-B gene overexpression was observed in rAl-CPI-treated group compared to DSS-exposed control and healthy mice. Furthermore, a reduction in IL-6 and TNF-A expression was found, and this was confirmed by the levels of these cytokines in colonic tissue. In conclusion, rAl-CPI reduces inflammation in a mouse model of DSS-induced colitis, probably by increasing the expression of anti-inflammatory cytokines and reducing pro-inflammatory ones.

Schistosoma japonicum cystatin attenuates murine collagen-induced arthritis.

Recombinant SjCystatin (rSjCystatin), a recombinant protein of Schistosoma japonicum cystatin, has been reported to have an effect on immunoregulation mediated by IL-10 induction. Rheumatoid arthritis (RA) is a common autoimmune inflammatory arthropathy, and recombinant immune-modulating drugs for RA treatment are under development. We aimed to study the putative immune regulation of rSjCystatin and its prophylactic/therapeutic effects on murine collagen-induced arthritis (CIA). CIA was induced in DBA/1 mice by inoculation with bovine collagen II (CII). rSjCystatin was administered prior or post development of CIA. The severity of CIA was assessed using established clinical and histopathological scoring systems. The incidence was also determined. The CII-specific antibodies in sera and cytokines in splenocyte culture supernatants were measured by ELISA. Th1/Th2/Th17 cells and Tregs development in splenocytes were monitored by flow cytometry. The inflammatory mediators in the diseased joint were semiquantitated by qPCR. Prophylactic injection of rSjCystatin attenuated paw clinical scores, incidence, and histopathology scores of joints in CIA mice. The arthritis-alleviative effects were closely associated with the augmentation of IL-4, IL-10, and collagen-specific IgG1, and with the distinct reduction of IFN-γ, collagen-specific IgG2a, and the marked decrease of proinflammatory cytokines IL-6, IL-17, and TNF-α and RANKL. The data indicate that rSjCystatin may prevent cartilage destruction and inflammation of joints in CIA mice. The effects are related to the inhibitory modulation of Th1 and Th17 and upregulation of Tregs and Th2 via a shift of cytokines profiling from Th1 to Th2 response.

AcCystatin, an immunoregulatory molecule from Angiostrongylus cantonensis, ameliorates the asthmatic response in an aluminium hydroxide/ovalbumin-induced rat model of asthma.

Epidemiological surveys have demonstrated that helminth infections are negatively related to atopic diseases, including asthma. Defining and characterising specific helminth molecules that have excellent immunomodulatory capacities as potential therapeutics for the treatment or prophylaxis of allergic manifestations are of great interest. AcCystatin, a cystatin protease inhibitor of Angiostrongylus cantonensis, is a homologue of other nematode cystatins with immunoregulatory properties. Here, we aim to determine the effects of AcCystatin on an ovalbumin/aluminium hydroxide (OVA/Al[OH]3)-induced rat model of asthma. Wistar rats were randomly divided into four groups, including a control group, an OVA/Al[OH]3-induced asthma group, a group receiving AcCystatin immunisation prior to OVA/Al[OH]3-induced asthma and a group receiving AcCystatin treatment after OVA/Al[OH]3-induced asthma. The numbers of eosinophils, basophils, neutrophils, lymphocytes and monocytes in the peripheral blood and of eosinophils in the bronchoalveolar lavage fluid (BALF) were counted for each animal. The expression levels of the cytokines interferon-γ, interleukin (IL) 4, IL-5, IL-6, IL-10, IL17A and tumour necrosis factor receptor-α in BALF, of OVA-specific immunoglobulin E in BALF and serum and of the chemokines eotaxin-1, eotaxin-2, eotaxin-3, MCP-1 and MCP-3 in lung tissue were measured. In addition, the degree of peribronchial and perivascular inflammation and the intensity of goblet cell metaplasia were qualitatively evaluated. The sensitised/challenged rats developed an extensive cell inflammatory response of the airways. AcCystatin administration significantly reduced the cellular infiltrate in the perivascular and peribronchial lung tissues and reduced both goblet mucous production and eosinophil infiltration. The rats that were treated with AcCystatin before or after sensitisation with OVA showed significant decreases in eotaxin-1, eotaxin-3 and MCP-1 expression in the lung tissue. The production of IL-4, IL-5, IL-6 and IL-17A and of OVA-specific IgE antibodies was also significantly reduced in AcCystatin-treated rats compared with untreated asthmatic rats. The AcCystatin treatment was associated with a significant increase in IL-10 levels. Our present findings provide the first demonstration that AcCystatin is an effective agent in the prevention and treatment of the airway inflammation associated with asthma.

Oral administration with attenuated Salmonella encoding a Trichinella cystatin-like protein elicited host immunity.

Trichinellosis is a public health problem and is regarded as an emergent/re-emergent disease in various countries. The cDNA encoding a cystatin-like protein (Ts-cystatin) was identified by immunoscreening intestinal muscle larvae cDNA libraries with serum from pigs experimentally infected with 20,000 Trichinella spiralis muscle larvae. To study its impact on host immunity, we chose a eukaryotic expression system based on several comparisons of immunogenicity between the two Salmonella typhimurium administration schemes, which indicated that the eukaryotic expression system was superior. Humoral IgG and mucosal IgA were measured to determine the antibody response. To explore whether Th1 and Th2 responses were responsible for the induced protection, Th1- and Th2-specific cellular transcription factors and the cytokine profile were examined. Changes in the T lymphocyte and macrophage populations were detected by flow cytometry. Lastly, parasitological examination was examined. The results showed that Ts-cystatin induced a Th1/Th2-mixed type of immune response and decreased STAT6 transcription. The intestinal adult recovery increased by 10.9% in the Ts-cystatin group, the Ts-cystatin group fecundity rate was decreased by 91%. Furthermore, the number of muscle larvae did not change compared with the control group. In conclusion, our results suggest that Ts-cystatin plays an important role in Trichinella resistance to rapid expulsion by the host and is worth further study.

[The statin dosage for achieving goal of cholesterol-lowering based on risk stratification in patients with ischemic cerebrovascular diseases].

OBJECTIVE: To explore statin dosages for targeting goal of LDL-C lowering on the basis of stroke risk stratification and the dosage-effective relation of statin and LDL-C lowering in Chinese patients with ischemic stroke and transient ischemic attack (TIA). METHODS: This is a prospective and open clinical trial patients with ischemic stroke/TIA within 6 months were enrolled and the dosages of atorvastatin were calculated based on risk stratification according to "Chinese Consensus for Prevention of Ischemic Stroke/TIA with Statin" (Chinese Consensus). A dose of 10 mg of atorvastatin daily to target LDL-C goal was taken as the standard dosage targeting goal (SDTG). Patients taking this dosage of atorvastatin constituted a SDTG group. Those who needed a daily dose of 20 mg or more of atorvastatin were randomized into an intensive dosage targeting goal (IDTG) group (atorvastatin 20 - 80 mg/d) and a standard dosage non-targeting goal (SDNTG) group (atorvastatin 10 mg/d without targeting goal). All patients took atorvastatin for 12 weeks. The primary outcome was the rate of targeting goal for LDL-C lowering at 2, 4 and 12 weeks, respectively and the secondary outcome was the occurence of recurrent stroke and other vascular events within 12 weeks. The main safety endpoint was serial adverse events including symptomatic intracranial hemorrhage. RESULTS: Altogether 102 cases were enrolled and 99 cases were followed up for 12 weeks. According to the Chinese Consensus, the rate of high risk, very high risk-I and very high risk-II was 44%, 28% and 28%, respectively. Targeting rate for LDL-C lowering was 77% - 85% at each time point in the SDTG and IDTG groups, being significantly higher than those in the SDNTG group (12% - 16%, P < 0.01). No significant difference was found concerning the occurrence of recurrent stroke, other vascular events and safety endpoints among the three groups. The amplitude of LDL-C lowering was 32% - 35%, 46% - 49%, 51% - 52% and 60% - 65% with corresponding to daily dosage of 10 mg, 20 mg, 40 mg and 80 mg atorvastatin. CONCLUSIONS: At least more than half of the patients after ischemic stroke/TIA need intensive statin therapy to target the LDL-C lowering goal. The dosage-effective relation of atorvastatin and LDL-C lowering in Chinese is similar to the reported data in other races.

Inactivation of harmful tumour-associated proteolysis by nanoparticulate system.

The primary aim in cancer therapy is to deliver anti-cancer drugs to their specific molecular targets in the tumour. Here we present a system composed of poly(d,l-lactide-co-glycolide) nanoparticles, cytokeratin specific monoclonal antibody and cystatin, a potent protease inhibitor, that can neutralize the excessive proteolytic activity associated with the invasive and metastatic potential of breast tumour cells. The antibody provides specific targeting of the delivery system to invasive breast epithelial cells and, additionally, prevents the generation of plasmin, a central extracellular protease involved in malignant progression. Polymeric nanoparticles rapidly enter the targeted cells and release the inhibitor cargo within the endosomes/lysosomes. The inhibitor is capable to inactivate lysosomal cysteine proteases, in particular cathepsin B, which is involved in the degradation of extracellular matrix inside the tumour cells. Our approach, which combines nanoparticulate delivery system with the inhibitory potential against extracellular and intracellular proteases, may improve the efficacy of therapy in patients with breast tumours compared to the application of individual protease inhibitors.

Cystatin C stimulates the differentiation of mouse osteoblastic cells and bone formation.

Cystatin C (CysC) is a natural cysteine proteinase inhibitor that suppresses the differentiation and bone-resorptive function of osteoclasts. By contrast, the effect of CysC on the differentiation and bone-formative function of osteoblasts has not been elucidated thoroughly. We examined the effects of CysC on mouse osteoblastic cells using in vitro cultures from bone marrow and calvaria and ex vivo calvarial cultures. CysC-stimulated cells showed increased alkaline phosphatase (ALP) activity, mineralization of the new bone matrix, and calvarial bone formation. The cells treated with CysC immunodepleted by anti-CysC antibody (iCysC) and a chemical papain-like cysteine proteinase inhibitor, E-64, did not induce mineralization. Elevated mRNA levels of bone morphogenetic protein (BMP)-2, the differentiation marker osteocalcin, and a master osteogenic transcription factor, Runx2, were observed in CysC-treated cells. These results suggest that CysC affects the BMP signaling cascades in osteoblastic cells and then promotes osteoblast differentiation, mineralization, and bone formation.

Intracellular delivery of cysteine protease inhibitor cystatin by polymeric nanoparticles.

Two polymers chitosan and poly(lactide-co-glycolide) copolymer (PLGA) were investigated to develop nanoparticles (NPs) for delivery of protein drug substance into tumour cells. Cystatin was selected as a model protein drug due to its high potential to inhibit cysteine proteases, known to trigger the invasive process. Ionotropic gelation of chitosan with tripolyposphate and precipitation of PLGA polymer from a double emulsion system by a solvent diffusion process were used to produce 250-300 nm in diameter NPs. The cellular uptake of NPs was tested on a transformed human breast epithelial cell line, MCF-10A neoT, characterized by an increased expression of cysteine proteases and highly invasive cell phenotype. The influence of NPs on cell viability was evaluated by MTT test showing IC50 400 microg/ml for PLGA and 5 mg/ml for chitosan NPs. As determined by fluorescence microscopy chitosan NPs did not enter the cells during 1-hour incubation whereas the same amount of PLGA NPs were in the cells already after 5 min of incubation. Cystatin delivered into MCF-10A neoT cells by PLGA NPs effectively inhibited intracellular proteolytic activity of cathepsin B, as detected by specific fluorogenic substrate Z-Arg2 cresyl violet. On the contrary, free cystatin in solution did not internalise into the cells and inhibit cathepsin B. To conclude, PLGA NPs with cystatin but not chitosan NPs were targeted through endocytosis to the lysosomal compartments that are rich of proteases enzymes. Our results suggest new strategy to inactivate intracellular tumour-associated proteases, and consequently the invasion behaviour of tumour cells, which could contribute to cancer therapy.

Recovery after a traumatic brain injury depends on diurnal variations effect of cystatin C.

Many studies indicate that the hour of the day at which the onset of stroke occurs is very important in patient recovery. Furthermore, multiple studies have been conducted which show that ischemia in rats produces different magnitudes of injury depending on the hour of the day at which it was induced. Using a traumatic brain injury (TBI) model, we analyzed the effect of the time of day on the recovery of rats and obtained a higher survival rate if TBI was induced at 01:00 h as compared with TBI induced at 13:00 h. We also analyzed the effect of the protease inhibitor cystatin C (CC) on the recovery of rats from TBI and found that it increased mortality and bleeding, and that these effects were more pronounced at 13:00 h.

Inhibition of protease in intact fish fillets by soaking in or injection of recombinant soy cystatin or bovine plasma.

Arrowtooth flounder (AF) fillets are known to contain a heat-activated cysteine protease similar to that found in Pacific whiting, which results in soft texture upon cooking. A crude recombinant soy cystatin (CRSC) produced by Escherichia coli, which has been shown to inhibit the protease(s) in Pacific whiting, was introduced into AF fillets by immersion or injection at one of three levels of inhibitory activity: 10 times less than, equal to, or 10 times greater than that of a 20% bovine plasma protein (BPP) solution, a known inhibitor of AF protease(s). Fillets treated with CRSC or BPP at equal inhibitory strength subsequently exhibited the same degree of protection against textural degradation during cooking. Fillets treated with CRSC at lesser or greater levels of inhibitory activity than those of BPP exhibited lesser or higher protection, accordingly. As revealed by SDS-PAGE, the outer portion of fillets soaked with inhibitory solutions was more effectively protected than the inner portion. Such differences between the outer and inner portions of the fillets were not evident when inhibitory solutions were injected into the fillets.

Purification and determination of inhibitory activity of recombinant soyacystatin for surimi application.

A recombinant soyacystatin (r-soyacystatin) was tested for its inhibitory activity against cysteine proteinase of Pacific whiting and its activity was compared to that of egg white cystatin. A recombinant soyacystatin expressed in Escherichia coli was purified to electrophoretic homogeneity using phenyl-Sepharose and DEAE-Sepharose. Native egg white cystatin was purified by using affinity chromatography on CM-papain-Sepharose generated in our lab. Egg white cystatin and soyacystatin were tested for proteinase inhibitory activity against commercial papain and also cathepsin L purified from Pacific whiting muscle. The r-soyacystatin exhibited papain-like protease inhibition activity comparable to that of the egg white cystatin, which could inhibit papain and Pacific whiting cathepsin L. The r-soyacystatin subsequently inhibited the autolytic activity of Pacific whiting surimi.

Poly(lactide-co-glycolide) nanoparticles as a carrier system for delivering cysteine protease inhibitor cystatin into tumor cells.

Cystatins are able to inhibit the tumor-associated activity of intracellular cysteine proteases cathepsins B and L and have been suggested as potential anticancer drugs. We have incorporated chicken cystatin, a model protein inhibitor of cysteine proteases, in poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) to improve its bioavailability and delivery into tumor cells. Cystatin-loaded NPs, 300-350 nm in diameter, were prepared by the double emulsion solvent diffusion method using low energy emulsification to preserve the biological activity of the protein. PLGA NPs and cystatin-loaded PLGA NPs at concentrations higher than 80 microg/ml were cytotoxic towards MCF-10A neoT cells, but not free cystatin at concentrations up to 5 microM. To visualize the uptake of cystatin into living MCF-10A neoT cells, NPs loaded with Alexa Fluor 488-labeled cystatin were added to the culture medium. They rapidly internalized into the cells, whereas the uptake of free-labeled cystatin was very slow. Cystatin, released from the NPs, effectively inhibited cathepsin B activity, as detected by degradation of specific Z-Arg-Arg cresyl violet substrate. In contrast, the same amount of free cystatin showed no inhibition of intracellular cathepsin B. Our results show that PLGA NPs are a useful carrier system for rapid delivery of protein inhibitors into tumor cells, enabling effective inhibition of intracellular proteolysis. The approach can be applied to other protein drugs active against intracellular targets.

Cystatin incorporated in poly(lactide-co-glycolide) nanoparticles: development and fundamental studies on preservation of its activity.

Preservation of biological activity is still a major challenge for successful formulation and delivery of protein drugs. Cystatin, a potential protein drug in cancer therapy, was incorporated in poly(lactide-co-glycolide) nanoparticles by the water-in-oil-in-water emulsion solvent diffusion technique. In order to preserve the biological activity of cystatin, a specific modification of the method of producing nanoparticles was introduced. The activity of cystatin was strongly influenced by the stirring rate during preparation and, to a lesser extent, by selected organic solvents. A synergistic effect of mechanical stirring and sonication, both at low energy levels, enabled nanoparticles to be formed without denaturing the cystatin. Nanoparticles produced by the optimised method ranged from 300 to 350 nm in diameter with 85% of the starting cystatin activity. The loading efficiency of cystatin depends on polymer type and ranged from 12 to 57%, representing an actual loading of 0.6-2.6% (w/w). Among various cryo-/lyoprotectants bovine serum albumin was identified as the most successful. The use of a protein protectant prior to nanoparticle formation was essential to maintaining the biologically active three-dimensional structure of cystatin. In addition, a specific type of poly(lactide-co-glycolide) polymer, particularly in terms of its functional groups, was identified to be important in retaining cystatin activity. Cystatin incorporated into nanoparticles in this way maintains its structural integrity, making it suitable for effective drug delivery.

Glycosylation modification improved the characteristics of recombinant chicken cystatin and its application on mackerel surimi.

The recombinant and glycosylation chicken cystatins were expressed and secreted in the broth of Pichia pastoris X-33 transformant with apparent molecular masses (M) of 14 and 55 kDa, respectively. The glycosylation cystatin (glycocystatin) contained a polysaccharide chain that was composed of 50 DP of mannose residues. Because of the polymannosyl chain, the inhibitory ability in glycocystatin was 90.8% of recombinant cystatin. In addition to freeze-thawing stability, the thermal and pH stabilities as well as the susceptibility of glycocystatin were also enhanced. Both cystatins could improve the mackerel surimi gel by inhibiting the gel softening, which was derived from the hydrolysis of catheptic cysteine proteinases. Despite the additional amount of glycocystatin (8 units), twice that of recombinant cystatin, the 40 and 15% increases in breaking force and deformation of gels were also observed. Accordingly, the surimi gel was further improved by enhancing the stability of chicken cystatin.

Prima facie evidence that a phytocystatin for transgenic plant resistance to nematodes is not a toxic risk in the human diet.

A protein-engineered rice cystatin (OcIDeltaD86) provides transgenic, partial crop resistance to plant nematodes. This study determined whether its oral uptake has adverse effects on male Sprague-Dawley rats when they are administered by oral gavage 0.1-10 mg OcIDeltaD86/kg body weight daily for 28 d. Body weight and water and food intakes were unaltered for most of the study. The only significant changes in fresh weight of nine organs were for the liver (4% decrease; P < 0.05) and the empty cecum (14% increase; P < 0.05) at the two lowest doses and the highest dose of OcIDeltaD86, respectively. No abnormalities in either organ were detected by histochemistry. There were no changes in the urine or in hematological variables measured, and blood serum revealed no dose-dependent responses for any of 17 variables measured. OcIDeltaD86 was degraded by boiling with a 50% loss of its inhibition of papain after 9.2 +/- 8.0 min. It also showed >95% loss of such inhibition after 15 s in simulated gastric fluid. The results suggest that the no effect level (NOEL) for OcIDeltaD86 is >10 mg/(kg. d). This provides a range of dietary exposure >200-2000 fold depending upon the promoter used to control its expression in potato.

Successful therapy of lethal murine visceral leishmaniasis with cystatin involves up-regulation of nitric oxide and a favorable T cell response.

The virulence of Leishmania donovani in mammals depends at least in part on cysteine proteases because they play a key role in CD4(+) T cell differentiation. A 6-fold increase in NO production was observed with 0.5 microM chicken cystatin, a natural cysteine protease inhibitor, in IFN-gamma-activated macrophages. In a 45-day BALB/c mouse model of visceral leishmaniasis, complete elimination of spleen parasite burden was achieved by cystatin in synergistic activation with a suboptimal dose of IFN-gamma. In contrast to the case with promastigotes, cystatin and IFN-gamma inhibited the growth of amastigotes in macrophages. Although in vitro cystatin treatment of macrophages did not induce any NO generation, significantly enhanced amounts of NO were generated by macrophages of cystatin-treated animals. Their splenocytes secreted soluble factors required for the induction of NO biosynthesis, and the increased NO production was paralleled by a concomitant increase in antileishmanial activity. Moreover, splenocyte supernatants treated with anti-IFN-gamma or anti-TNF-alpha Abs suppressed inducible NO generation, whereas i.v. administration of these anticytokine Abs along with combined therapy reversed protection against infection. mRNA expression and flow cytometric analysis of infected spleen cells suggested that cystatin and IFN-gamma treatment, in addition to greatly reducing parasite numbers, resulted in reduced levels of IL-4 but increased levels of IL-12 and inducible NO synthase. Not only was this treatment curative when administered 15 days postinfection, but it also imparted resistance to reinfection. These studies provide a promising alternative for protection against leishmaniasis with a switch of CD4(+) differentiation from Th2 to Th1, indicative of long-term resistance.

Translocation of orally administered rat salivary cystatin into serum and kidney.

This translocation was followed by means of a sensitive enzyme immunoassay. Salivary cystatin could be detected in serum, oesophagus, stomach, small intestine and kidney 15 min after oral administration. The salivary cystatin level in serum and kidney extract was maximal 15-60 and 30-60 min, respectively, after its administration and increased dose-dependently. Chromatography showed that the cystatin molecule in serum was identical to that in the submandibular saliva used for oral administration, but differed from that in kidney extract. These results suggest that salivary cystatin is absorbed intact by the gastrointestinal tract and reaches the bloodstream, from which it is taken up by the kidney and modified.