Activity In Serum Of Mice Research Articles

Interleukin-37 ameliorates cigarette smoke-induced lung inflammation in mice

Cigarette smoking (CS) is the leading cause of chronic obstructive pulmonary disease, and its severity is closely related to lung inflammation. Interleukin (IL)-37 is a newly discovered member of the IL-1 family with anti-inflammatory activity. Our study aimed to elucidate the effect of IL-37 on CS-induced lung inflammation in mice. In this study, mice were exposed to six cigarettes for 1 h three times daily (4 h smoke-free intervals) for 10 consecutive days. Mice were treated intranasally with IL-37-expressing lentivirus and empty lentivirus particles 1 day before the first CS or sham exposure. Mice were sacrificed on day 11 to evaluate the effect of IL-37 on CS-induced pulmonary inflammation in mice. Administering IL-37-expressing lentivirus significantly reduced CS-induced weight loss in mice compared to empty lentivirus controls (P < 0.05). Histological analysis showed that IL-37 significantly alleviated inflammatory cell recruitment, alveolar septum enlargement, alveolar wall attenuation, mucus hypersecretion, and goblet cell metaplasia in mouse lungs (P < 0.001). IL-37 expression also significantly inhibited CS-induced increases in inflammatory cells (including lymphocytes, neutrophils, and macrophages) in mouse lungs (P < 0.05), as well as pro-inflammatory cytokines such as IL-1β, IL-6, IL-17, monocyte chemotactic protein-1 and tumor necrosis factor-α production (P < 0.05). IL-37 also significantly reduced myeloperoxidase activity in mouse serum (P < 0.01) and lung tissues (P < 0.001). Therefore, IL-37 can ameliorate CS-induced pulmonary inflammation in mice and IL-37 may be a potential therapeutic strategy for CS-induced lung inflammatory diseases.

Development and evaluation studies of Corylin loaded nanostructured lipid carriers gel for topical treatment of UV-induced skin aging

We prepared nanostructured lipid carriers (NLC) to promote skin permeation of Corylin so that it can increase its effect on photoaging. Corylin-NLCs were prepared and characterized based on morphology, particle size, zeta potentials, FTIR and DSC. In vitro, we assess the cytotoxicity and lactate dehydrogenase (LDH) of HaCaT cells irradiated by UVB. Expression of antioxidant enzymes was evaluated by commercial kits. The effects of Corylin-NLC on apoptosis were confirmed by flow cytometry and western blotting. In vivo, we use UV irradiated mouse as the oxidative stress model to assess the therapeutic effect of Corylin loaded NLC gel. We identified the Corylin-NLCs can significantly suppress the LDH release, decrease MDA content, increase in CAT, SOD, GSH-Px activity, increase the expression of Bcl-2/Bax protein and reduce the expression of cleaved caspase-3/caspase-3 protein on UVB induced HaCaT cells. The histopathological lesions were significantly improved and observably decreased MDA level, increase in antioxidant enzymes activity in serum of mice by pretreatment of Corylin-NLCs gel. Overall, this study proposes a promising strategy for improving the therapeutic efficacy of photoaging.

Hepatoprotective Effect of Apigenin Against Liver Injury via the Non-canonical NF-κB Pathway In Vivo and In Vitro

Apigenin, a flavonoid found in many plants, has various biological properties. We aimed to investigate the anti-inflammatory and anti-oxidative activity of apigenin against carbon tetrachloride (CCl4)-induced acute liver injury in mice and hydrogen peroxide (H2O2)-induced oxidative stress in HepG2 cells and possible mechanism. In vivo, apigenin significantly reduced alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity in serum of mice challenged by CCl4 and markedly alleviated the lipid peroxidation as indicated by the increased level of superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidases (GSH-Px) and catalase (CAT), and the decreased malondialdehyde (MDA) in liver tissue. Apigenin also ameliorated inflammation by downregulating tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and upregulating IL-10. Consistently, the elevated ALT and AST level; the impaired balance between SOD, GSH activity, and excessive ROS; and the increased gene expression of TNF-α and IL-6 resulting from H2O2-induced oxidative stress were restored by apigenin. Moreover, the results from Western blot, real-time qPCR, and immunofluorescence assay indicated that apigenin enhanced the activity of TNF receptor-associated factor (TRAF) 2/3 and cellular inhibitor of apoptosis protein (c-IAP) 1, ameliorated NF-κB-inducing kinase (NIK), and mediated the nuclear translocation of NF-κB2, therefore had an inhibitory effect on the non-canonical NF-κB pathway which was activated in both models. siNIK canceled the protective effect of apigenin on H2O2-induced HepG2 cells. Altogether, our results demonstrated that apigenin mitigated liver injury by ameliorating inflammation and oxidative stress through suppression of the non-canonical NF-κB pathway, indicating the potential of apigenin for treatment of the liver injury.

Mechanism in bradycardia induced by Trimethyltin chloride: Inhibition activity and expression of Na+/K+-ATPase and apoptosis in myocardia.

Trimethyltin chloride (TMT) is a stabilizer by-product in the process of manufacturing plastic, which is a kind of very strong toxic substance, and has acute, cumulative and chronic toxicity. TMT may cause bradycardia in patients with occupational poisoning, the mechanism of which has not been reported. This study explored the mechanism of TMT resulting in bradycardia of C57BL/6 mice. TMT was administered to mice to measure heart rate, serum succinate dehydrogenase (SDH) level, and myocardial Na+/K+-ATPase activity and expression. The effects of TMT on myocardial apoptosis were observed by changing the expressions of caspase-3, Bax and Bcl-2 in myocardium. It was found that the heart rate and SDH activity in serum of mice gradually decreased with the increase of TMT dose compared with the control group. The activity and the expression of Na+/K+-ATPase in the heart tissue of mice exposed to TMT was measured and gradually decreased with the increase of dose and time. We measured the expression of Bcl-2, Bax, caspase-3 and cleaved caspase-3 in the heart tissues of TMT exposed mice and found that the expressions of Bax, caspase-3 and cleaved caspase-3 increased and the expressions of Bcl-2 decreased in the heart tissues of the TMT-exposed mice at different doses. With the extension of TMT exposure time, the expression of Bax and caspase-3 increased and the expression of Bcl-2 decreased in the heart tissues of TMT exposed mice. Our findings suggest the mechanisms of TMT resulting in bradycardia may be associated with the inhibited activity and decreased content of Na+/K+-ATPase, thus further leading to the changes of Bcl-2, Bax, caspase-3 and cleaved caspase-3 in the mice's ventricular tissues.

Engineering of monobody conjugates for human EphA2-specific optical imaging.

In a previous study, we developed an E1 monobody specific for the tumor biomarker hEphA2 [PLoS ONE (2015) 10(7): e0132976]. E1 showed potential as a molecular probe for in vitro and in vivo targeting of cancers overexpressing hEphA2. In the present study, we constructed expression vectors for E1 conjugated to optical reporters such as Renilla luciferase variant 8 (Rluc8) or enhanced green fluorescent protein (EGFP) and purified such recombinant proteins by affinity chromatography in E. coli. E1-Rluc8 and E1-EGFP specifically bound to hEphA2 in human prostate cancer PC3 cells but not in human cervical cancer HeLa cells, which express hEphA2 at high and low levels, respectively. These recombinant proteins maintained >40% activity in mouse serum at 24 h. In vivo optical imaging for 24 h did not detect E1-EGFP signals, whereas E1-Rluc8 showed tumor-specific luminescence signals in PC3 but not in HeLa xenograft mice. E1-Rluc8 signals were detected at 4 h, peaked at 12 h, and were undetectable at 24 h. These results suggest the potential of E1-Rluc8 as an EphA2-specific optical imaging agent.

Transdermal praziquantel administration attenuates hepatic granulomatosis in mice infected with Schistosoma japonicum.

Liver granuloma is a major pathogenic factor responsible for schistosomiasis, and no effective drugs or therapy methods to treat it have been found so far. Praziquantel (PZQ) has shown some anti-schistosomal effect, but little information is available about the effect of PZQ-prolonged administration on granuloma formation around schistosome eggs. Herein, we investigated the effect of PZQ on hepatic granuloma formation by treating the mice infected with Schistosoma japonicum using a long-term PZQ transdermal delivery. The results showed that the mean area of granulomas in the group treated with PZQ transdermal agent was (175.47 ± 116.73) × 10(3) μm(2) at the 49th day postinfection and (71.96 ± 45.99) × 10(3) μm(2) at the 56th day, while that in the control group was (304.51 ± 140.55) × 10(3) μm(2) and (526.44 ± 268.06) × 10(3) μm(2), respectively. The content of hydroxyproline in the livers of mice approached to the normal level on the 154th day in the treatment group, but it continued to increase from the 28th day to the 154th day after infection in the control group and nontreatment group. The ALT activity in serum of mice in the treatment group was also significantly lower than that in the control group (*P ≤ 0.05). Our results suggest that the long-term PZQ transdermal delivery is critical in the therapeutic approach to control the progress of hepatic schistosomiasis induced by egg granulomas.

Chitotriosidase Activity in the Blood Serum and Organs of Mice of Various Strains under the Infl uence of Chitin

Mouse chitotriosidase cleaving chitin belongs to the family of mammalian chitinases, whose biological functions are poorly understood. Chitotriosidase activity in mouse serum was shown to be much higher than in humans. The following interstrain differences were revealed in mouse chitotriosidase activity: GR>C57Bl/6>BALB/c>A/Sn>CBA. Chitotriosidase activity in CBA mice was lowest and practically did not differ from that in C3H/He and ICR mice. No sex-related differences were found in enzyme activity. Hybrids of opposite strains CBA and C57Bl/6 were characterized by dominant inheritance of this sign (elevated activity of chitotriosidase in the serum). Intragastric administration of chitin in a single dose of 100 mg/kg was followed by a decrease in chitotriosidase activity in the lungs, but not in the blood serum and homogenate of gastric cells from CBA mice. These data indicate that intragastric administration of chitin does not induce chitotriosidase in mice.

321 Analysis of Combinatorial Effect of Multikinase Inhibitor (Sorafenib, Sunitinib) or Cetuximab with MEK or mTOR Inhibitors in Human Head and Neck Cancer Cells

Background: Prostate cancer is the most common cancer in men. Although screening, radiation, surgery and hormone ablation therapy have greatly improved the detection and treatment of early stage prostate cancer, few options exist to treat metastatic, castrate-resistant prostate cancer (CRPC). We have developed a therapeutic approach that uses a bispecific SCORPION (multi-specific protein therapeutic) molecule that redirects T cell cytotoxicity against cells expressing a common prostate cancer antigen, PSMA (Prostate Specific Membrane Antigen). SCORPION molecules are antibody-like therapeutics containing two sets of binding domains linked to immunoglobulin Fc domains, which extends the half-life of the molecule in vivo. Materials and Methods: Cytotoxic activity was examined in vitro by treating PSMA(+) cell lines (LNCaP, C4−2B, MDA-PCa-2b) and PSMA(−) cell lines (DU-145, BxPC-3) with SCORPION molecules in the presence of purified human T cells or human peripheral blood mononuclear cells (PBMCs). Cytotoxic activity was determined by chromium release assays or by incorporation of a label such as propidium iodide or 7-aminoactinomycin D. CFSE-labeled T cells were assessed for activation and proliferation in a similar setting using multi-color flow cytometry. To evaluate serum stability, SCORPION proteins were incubated in mouse serum and monitored for functional activity. Results: SCORPION molecules targeting PSMA and CD3 efficiently redirected T cell cytotoxicity against PSMA(+) cell lines in vitro at low picomolar concentrations. Cytotoxic activity was target dependent and required the presence of T cells. T cells were activated and proliferated in response to the SCORPION therapeutic in the presence of PSMA(+) target cells; no proliferation was observed in response to PSMA(−) cells. SCORPION proteins were stable to freeze/thaw in mouse serum and showed stable functional activity in mouse serum when incubated at 37oC for up to one week. Conclusions: These studies show that anti-PSMA× anti-CD3 SCORPION therapeutics may be efficient agents for redirecting T cell cytotoxicity and show promise as potential therapeutics in CRPC.

320 Comparative Pharmacokinetics of Trastuzumab-US and Trastuzumab-EU and the Potential Biosimilar Trastuzumab-Pfizer in Male CD-1 Mice

Background: Prostate cancer is the most common cancer in men. Although screening, radiation, surgery and hormone ablation therapy have greatly improved the detection and treatment of early stage prostate cancer, few options exist to treat metastatic, castrate-resistant prostate cancer (CRPC). We have developed a therapeutic approach that uses a bispecific SCORPION (multi-specific protein therapeutic) molecule that redirects T cell cytotoxicity against cells expressing a common prostate cancer antigen, PSMA (Prostate Specific Membrane Antigen). SCORPION molecules are antibody-like therapeutics containing two sets of binding domains linked to immunoglobulin Fc domains, which extends the half-life of the molecule in vivo. Materials and Methods: Cytotoxic activity was examined in vitro by treating PSMA(+) cell lines (LNCaP, C4−2B, MDA-PCa-2b) and PSMA(−) cell lines (DU-145, BxPC-3) with SCORPION molecules in the presence of purified human T cells or human peripheral blood mononuclear cells (PBMCs). Cytotoxic activity was determined by chromium release assays or by incorporation of a label such as propidium iodide or 7-aminoactinomycin D. CFSE-labeled T cells were assessed for activation and proliferation in a similar setting using multi-color flow cytometry. To evaluate serum stability, SCORPION proteins were incubated in mouse serum and monitored for functional activity. Results: SCORPION molecules targeting PSMA and CD3 efficiently redirected T cell cytotoxicity against PSMA(+) cell lines in vitro at low picomolar concentrations. Cytotoxic activity was target dependent and required the presence of T cells. T cells were activated and proliferated in response to the SCORPION therapeutic in the presence of PSMA(+) target cells; no proliferation was observed in response to PSMA(−) cells. SCORPION proteins were stable to freeze/thaw in mouse serum and showed stable functional activity in mouse serum when incubated at 37oC for up to one week. Conclusions: These studies show that anti-PSMA× anti-CD3 SCORPION therapeutics may be efficient agents for redirecting T cell cytotoxicity and show promise as potential therapeutics in CRPC.

Alterations in Wnt pathway activity in mouse serum and kidneys during lupus development

The canonical Wnt/β-catenin pathway was recently identified as a factor in the pathogenesis of several renal diseases. The aim of this study was to evaluate Wnt signaling activity during disease development in a murine model of lupus nephritis. Wnt activity and Dkk-1 expression were serially assayed in the serum and kidneys of (NZB × NZW)F(1) mice during progression of lupus nephritis. The effects of serum obtained from mice with lupus and serum-equivalent concentrations of Dkk-1 on mesangial cells were assessed in vitro. Gene expression analyses revealed increased canonical Wnt pathway activity in kidneys during development of lupus nephritis, paralleled by an increase in renal and serum levels of the Wnt inhibitor Dkk-1. Sera obtained from proteinuric-stage (NZB × NZW)F(1) mice showed strong Wnt-inhibitory effects in vitro. Dkk-1 concentrations comparable to those observed in lupus-prone mice induced apoptosis in tubular and mesangial cells in vitro, whereas no such effect was seen for the range of concentrations observed in young prediseased mice and control BALB/c mice. These data demonstrate that renal Wnt signaling activity is increased in lupus and is accompanied by an increase in renal and serum levels of Dkk-1. The Wnt pathway is involved in the turnover of extracellular matrix constituents and represents a potential mediator of the morphologic changes that occur within the glomerulus during the development of nephritis. Furthermore, increased levels of Dkk-1 serve as a potential proapoptotic stimulus in vitro and possibly in vivo and could be an important element in the initiation and progression of systemic and end-organ disease manifestations in systemic lupus erythematosus.

Candida albicans, Cryptococcus neoformans or Aspergillus fumigatus Induces an Antifungal Activity in Mouse Serum, which is Different from Transferrin

It has been reported that administration of Candida albicans into mouse induces an antifungal activity in serum, which has been identified as transferrin. In the present study, we show that not only C. albicans, but also other fungus such as Cryptococcus neoformans or Aspergillus fumigatus similarly can induce an antifungal activity in mouse serum. This antifungal activity was inhibited by the addition of ferrous ion, indicating that the growth inhibition of C. albicans was due to deficiency of ferrous ion, which may be caused by transferrin. Indeed, addition of transferrin in an in vitro assay system using RPMI1640 culture medium inhibited the growth of C. albicans, C. neoformans or A. fumigatus. However, when C. albicans was grown in RPMI1640 medium with 10% fetal bovine serum (FBS), transferrin was unable to inhibit the growth of C. albicans, in sharp contrast, when C. albicans treated mouse serum was added instead of FBS, the growth of the organism was inhibited. Similar results were obtained when C. neoformans or A. fumigatus was used. Taken together, the results suggest that antifungal activity induced by C. albicans, C. neoformans or A. fumigatus was not due to transferrin but likely due to other unknown serum proteins, which may cut off the source of iron for the growth of these fungi.

Effects of Some Antibiotics on Paraoxonase from Human Serum in Vitro and from Mouse Serum and Liver in Vivo

Paraoxonase (PON1, EC 3.1.8.1) is an esterase protein which plays multifunctional role in metabolism. Therefore, in this study the effects of commonly used antibiotics, namely sodium ampicillin, ciprofloxacin, rifamycin SV and clindamycin phosphate, on human PON1 were investigated in vitro and in vivo. Human serum paraoxonase (PON1) was separately purified by ammonium sulfate precipitation and hydrophobic interaction chromatography. The in vitro effects of the antibiotics in purifying human serum paraoxonase was determined using paraoxon as a substrate, and the IC50 values of these drugs exhibiting inhibition effects were found from graphs of hydratase activity % by plotting the concentration of the drugs. It was determined that sodium ampicillin, ciprofloxacin, and clindamycin phosphate were effective inhibitors on human serum PON1, and the inhibition kinetics of interaction of sodium ampicillin, ciprofloxacin, and clindamycin phosphate with the human serum PON1 was also determined, with the Ki of sodium ampicillin, ciprofloxacin, and clindamycin phosphate being 0.00714+/-0.00068, 6.5x10(-6)+/-4.59x10(-7), 0.0291+/-0.0077 mM, respectively. The in vivo effects of the antibiotics on paraoxonase enzyme activity in mouse serum and liver PON1 were also investigated. Mouse liver PON1 activity showed a statistically significant change at 2, 4 and 6 h of drug application in vivo. Sodium ampicillin and clindamycin phosphate exhibited about 80% mouse liver PON1 at 2 or 4 h (p: 0.034, 0.003 and 0.021, respectively). In addition, ciprofloxacin and rifamycin SV only showed inhibition at 4 h incubation. Sodium ampicillin (17.12 mg/kg) lead to a significant decrease in mouse serum PON1 after 4 h drug administration. Ciprofloxacin (3.2 mg/kg), rifamycin SV (3.56 mg/kg) and clindamycin phosphate (2.143 mg/kg) did not exhibit any inhibition effect for the mouse serum PON1, in vivo.

A modified HIV challenge assay in mice by using luciferase-expressing vaccinia virus

In this study, we developed a simple and sensitive assay in mice for a challenge experiment by using a recombinant vaccinia virus dual-expressing antigen (HIV Env gp160) and firefly luciferase. This assay can detect the vaccine effect at real-time in vivo by using a small amount of mouse serum. The luciferase activity in mouse serum was in agreement with the viral titer in the ovary. This assay would be applicable as a challenge model for infectious diseases.

Protective immune responses to meningococcal C conjugate vaccine after intranasal immunization of mice with the LTK63 mutant plus chitosan or trimethyl chitosan chloride as novel delivery platform

Chitosan and its derivative N-trimethyl chitosan chloride (TMC), given as microparticles or powder suspensions, and the non-toxic mucosal adjuvant LTK63, were evaluated for intranasal immunization with the group C meningococcal conjugated vaccine (CRM-MenC). Mice immunized intranasally with CRM-MenC formulated with chitosan or TMC and the LTK63 mutant, showed high titers of serum and mucosal antibodies specific for the MenC polysaccharide. Neither significant differences were observed between microparticle formulations and powder suspensions nor when LTK63 was pre-associated to the delivery system or not. The bactericidal activity measured in serum of mice immunized intranasally with the conjugated vaccine formulated with the delivery systems and the LT mutant was superior to the activity in serum of mice immunized sub-cutaneously. Importantly, intranasal but not parenteral immunization, induced bactericidal antibodies at the nasal level, when formulated with both delivery system and adjuvant.

Separation and quantitative recovery of mouse serum arylesterase and carboxylesterase activity

Paraoxonase-1 (PON1) is known to be associated with high density lipoproteins. We optimized buffer conditions to obtain quantitative recovery of PON1 (arylesterase) activity and analyzed the distribution of PON1 in mice using a combination of size-exclusion chromatography and ultracentrifugation. Size-exclusion chromatography of mouse serum separated the esterase activity into two peaks, one overlapping the high density lipoproteins and a second peak of lower molecular weight, consistent with serum carboxylesterase, which accounted for approximately 20% of the total esterase activity of normal mouse serum. Using conditions for the quantitative recovery of arylesterase activity, we fractionated serum by ultracentrifugation into d < 1.21 g/ml, d < 1.25 g/ml, d > 1.21 g/ml, and d > 1.25 g/ml fractions. We observed that PON1 arylesterase activity and mass were isolated in the d < 1.21 g/ml fraction and that serum carboxylesterase was recovered in the d > 1.25 g/ml fraction. The significance of the confounding of PON1 arylesterase activity by serum carboxylesterase was demonstrated by studying mice challenged with a high-fat, high-cholate diet for 14 days. It was shown that all of the decrease in arylesterase activity in response to this diet is attributable to the HDL-associated arylesterase activity (PON1). We conclude that mouse PON1 is quantitatively associated with high density lipoproteins. The contribution of serum carboxylesterase to the total esterase activity significantly confounds the interpretation of total arylesterase activity in mouse serum.

Role of the complement-lectin pathway in anaphylactoid reaction induced with lipopolysaccharide in mice.

We show that Proteus vulgaris O25 (PO25) lipopolysaccharide (LPS) induced an anaphylactoid reaction not only in wild-type and in lipid A non-responding mice but also in recombinase-activating gene-2-deficient (RAG-2(-/-)) and in mast cell-deficient (W/Wv) animals. Western blot analysis indicated that PO25 LPS bound to Ra-reactive factor (RaRF), the complex of mannan-binding lectins (MBL) and MBL-associated serine proteases. Binding of RaRF to PO25 LPS led to the activation of C4 component without participation of either C1 or Ig, via the lectin pathway. Relative concentration of RaRF and hemolytic activity in mouse serum decreased rapidly during the process of anaphylactoid reaction. A significant drop of MBL-A, but not MBL-C level was observed. Administrationwith antiserum to RaRF prevented animals from death as a consequence of the inhibition of interaction of RaRF with the carbohydrate target and complement activation. These results indicate that complement-lectin pathway activation is responsible for the anaphylactoid reaction induced with LPS in muramyldipeptide-primed mice. RaRF also activated fibrinogen in vitro suggesting the involvement of the coagulation system in the process investigated.

Changes in cystine aminopeptidase (oxytocinase) activity in mouse serum, placenta, uterus and liver during pregnancy or after steroid hormone treatments.

Changes in cystine aminopeptidase (CAP) activity in serum, placenta, uterus and liver in mice under various physiological conditions were examined by enzymatic analysis using S-benzyl-L-cysteine-4-methylcoumaryl-7-amide as a substrate. Changes in serum CAP activity during pregnancy were less remarkable than those reported in humans; the activity was highest at day 13 of pregnancy and lowest at day 17. During the estrous cycle, the serum CAP level was high at diestrus, as high as that at day 13 of pregnancy. The activity in the male serum was significantly low compared to that in the diestrous serum. Although the CAP level was especially high in the maternal placenta, levels were also high in the fetal placenta, uterus and liver as compared with the serum, suggesting CAP synthesis in these tissues. The CAP activity in the uterine tissue was lower in pregnant than normal cycling mice. Furthermore, the serum CAP activity was modulated by estrogen and progesterone both in females and males, and by androgen in males. The relevance of these findings to the physiological role of CAP was discussed.

Hepatotrophic activity in mouse serum infected with plerocercoids ofSpirometra erinacei

To investigate the mechanism by which liver weight increases during plerocercoid infections as well as the possible existence of a hepatocyte-growth-factor (HGF)-like substance in the serum of mice infected with Spirometra erinacei plerocercoids, liver DNA synthesis was measured in vivo and in vitro. Infection with S. erinacei plerocercoids significantly stimulated DNA synthesis in mouse parenchymal hepatocytes prior to the increase in liver weight, at least partly by stimulating the induction of the salvage pathways of pyrimidine biosynthesis. Furthermore, infected mouse serum directly stimulated DNA synthesis in cultured mouse parenchymal hepatocytes. These results suggest that an HGF-like substance is present in the serum of mice infected with S. erinacei plerocercoids.

Priming Effect of Muramyl Peptides for Induction by Lipopolysaccharide of Tumor Necrosis Factor Production in Mice

Lipopolysaccharide-induced necrosis of grafted tumors was potentiated by several hydrophilic and lipophilic muramyl dipeptide (MDP) derivatives administered a few hours prior to small amounts of lipopolysaccharide (LPS) in spite of low titers of induced circulating tumor necrosis factor (TNF). However, pretreatment with MDP derivatives did increase the level of TNF in the blood of mice challenged by a greater dose of LPS. The TNF amount in 2 h postendotoxin mouse serum reached a peak when the glycopeptide had been given 6 h before the challenge, being approximately 100-fold above that obtained in unprimed mice. The cytotoxic activity in mouse serum was inhibited by rabbit antibodies raised against recombinant mouse TNF. Although there exists a toxic synergism between BCG or MDP and endotoxin, the effect of certain MDP derivatives was not related to an increased susceptibility to the toxicity of LPS.

Protective and pathological activity in serum of mice developing resistance toPlasmodium bergheiinfection

The serum from mice developing resistance against Plasmodium berghei infection using chemotherapeutic treatment has been analysed in vivo and in vitro. During the immunization period pathological as well as protective activities which could be transferred by serum were generated. The pathological activity, which was defined as destruction of erythrocytes in normal recipient mice, was generated early in the immunization procedure, peaked at day 21, and decreased to undetectable levels by day 35. After reinfection of the donor mice the pathological activity reappeared in the serum, and was maintained for at least 56 days. Analysis of the transferred serum samples showed the presence of anti-erythrocyte antibodies (ELISA), but no correlation with the in-vivo anti-erythrocyte effect could be found. The anti-erythrocyte effect of the serum samples indirectly increased the parasitaemia in the recipient mice through the induction of reticulocytosis. The protective effect of the serum samples could only be detected in samples taken from animals beyond day 61 of the immunization procedure. This net protective effect was reflected in a decreased parasitaemia at 7 days after challenge of the recipient mice with P. berghei infected erythrocytes. The protective activity of the serum was correlated with high titres of anti-erythrocyte antibodies. Anti-erythrocyte antibody titres were strongly correlated with titres against heterologous red blood cells as well as total immunoglobulin content of the serum samples, indicative of polyclonal activation of lymphocytes. Except for IgG1, all (sub-)classes were elevated during the immunization procedure, of which IgG3 was abundant. After immunity was obtained these immunoglobulin levels remained high, and the relative amount of IgG1 in the serum was restored.