Angelica sinensis down-regulates hydroxyproline and Tgfb1 and provides protection in mice with radiation-induced pulmonary fibrosis

Pulmonary fibrosis is a common delayed side effect of radiation therapy, and it has a poor prognosis. Tgfb1 is a potent chemoattractant for fibroblasts and stimulates the production of collagen, the protein that contains hydroxyproline. Since collagen is by far the most abundant protein in the lung, comprising 60-70% of the tissue mass, analysis of the hydroxyproline content in lung tissues provides a reliable quantitative index for pulmonary fibrosis. Thus hydroxyproline and Tgfb1 may be involved in the development of fibrosis. In this study, we investigated radiation-induced pulmonary fibrosis in a mouse model. C57BL/6 mice were assigned into four groups: no treatment, treated with Angelica sinensis treated only, X-irradiated only (a single fraction of 12 Gy to the thorax), and Angelica sinensis treatment plus radiation. We assayed expression of hydroxyproline and the mRNA and protein of Tgfb1 in the four groups. We found that Angelica sinensis down-regulated the production of Tgfb1 and hydroxyproline in mice with radiation-induced pulmonary fibrosis. This study has demonstrated for the first time that Angelica sinensis inhibits the progress of radiation-induced pulmonary fibrosis, possibly by down-regulating the expression of the proinflammatory cytokine Tgfb1. These data suggest that Angelica sinensis may be useful in preventing and/or treating radiation-induced pulmonary fibrosis in the clinic.     

Epithelial expression of TIMP-1 does not alter sensitivity to bleomycin-induced lung injury in C57BL/6 mice

Matrix metalloproteinases (MMPs) are mediators of lung injury, and their activity has been associated with the development of pulmonary fibrosis. To understand how MMPs regulate the development of pulmonary fibrosis, we examined MMP expression in two strains of mice with differing sensitivities to the fibrosis-inducing drug bleomycin. After a single intratracheal injection of the drug, bleomycin-sensitive C57BL/6 mice showed increased expression for MMPs (-2, -7, -9, -13) at both 7 and 14 days posttreatment compared with the bleomycin-resistant BALB/c strain. In addition, TIMP-1, an endogenous inhibitor of MMPs, was upregulated in the lungs of C57BL/6 mice but not BALB/c mice. We designed two strategies to decrease MMP expression to potentially decrease sensitivity of C57BL/6 mice: 1) we engineered C57BL/6 mice that overexpressed TIMP-1 in their lungs via surfactant protein C (SP-C) promoter; and 2) we inhibited expression of MMPs independent of TIMP-1 by knocking out metallothionein (MT), a critical zinc binding protein. SP-C-TIMP-1 mice reduced MMP expression in response to bleomycin. However, they were equally sensitive to bleomycin as their wild-type counterparts, displaying similar levels of hydroxyproline in the lung tissue. MT null mice displayed decreased lung activity of MMPs with no change in TIMP-1. Nonetheless, there was no difference between the MT null and wild-type control littermates with regards to any of the lung injury parameters measured. We conclude that although TIMP-1 expression is differentially regulated in fibrosis-sensitive and fibrosis-resistant strains, epithelial overexpression of TIMP-1 does not appear to substantially alter fibrotic lung disease in mice.     

Enalapril protects mice from pulmonary hypertension by inhibiting TNF-mediated activation of NF-kappaB and AP-1

The present study was undertaken to investigate the effects of treatment with the angiotensin-converting enzyme (ACE) inhibitor enalapril in a mouse model of pulmonary hypertension induced by bleomycin. Bleomycin-induced lung injury in mice is mediated by enhanced tumor necrosis factor-alpha (TNF) expression in the lung, which determines the murine strain sensitivity to bleomycin, and murine strains are sensitive (C57BL/6) or resistant (BALB/c). Bleomycin induced significant pulmonary hypertension in C57BL/6, but not in BALB/c, mice; average pulmonary arterial pressure (PAP) was 26.4 +/- 2.5 mmHg (P < 0.05) vs. 15.2 +/- 3 mmHg, respectively. Bleomycin treatment induced activation of nuclear factor (NF)-kappaB and activator protein (AP)-1 and enhanced collagen and TNF mRNA expression in the lung of C57BL/6 but not in BALB/c mice. Double TNF receptor-deficient mice (in a C57BL/6 background) that do not activate NF-kappaB or AP-1 in response to bleomycin did not develop bleomycin-induced pulmonary hypertension (PAP 14 +/- 3 mmHg). Treatment of C57BL/6 mice with enalapril significantly (P < 0.05) inhibited the development of pulmonary hypertension after bleomycin exposure. Enalapril treatment inhibited NF-kappaB and AP-1 activation, the enhanced TNF and collagen mRNA expression, and the deposition of collagen in bleomycin-exposed C57BL/6 mice. These results suggest that ACE inhibitor treatment decreases lung injury and the development of pulmonary hypertension in bleomycin-treated mice.     

The gene transfer of soluble VEGF type I receptor (Flt-1) attenuates peritoneal fibrosis formation in mice but not soluble TGF-beta type II receptor gene transfer

Peritoneal fibrosis formation is a consequence of inflammation/injury and a significant medical problem to be solved. The effects of soluble VEGF receptor type I (sFlt-1) gene transfer on experimental peritoneal fibrosis were examined and compared with soluble transforming growth factor-beta (TGF-beta) receptor type II (sTGF beta RII) gene transfer. Male C57BL/6 mice were injected with 1.5 x 10(8) plaque-forming unit of adenovirus encoding active TGF-beta (AdTGF beta) intraperitoneally. Some mice had been treated with sTGF betaRII or sFlt-1 plasmid injection into skeletal muscle with electroporation 4 days before virus administration. Mice were euthanized at day 14 after virus administration. AdTGF beta induced significant elevation of serum active TGF-beta, caused significant inflammatory response [weight loss, elevation of serum amyloid-P (SAP) and IL-12, increased expression of monocyte chemoattractant protein-1 (MCP-1) mRNA], and induced marked thickening of the peritoneum and collagen deposition. Gene transfer of sFlt-1 reduced the collagen deposition approximately 81% in mesenteric tissue. Treatment with sFlt-1 decreased ICAM-1 and MCP-1 mRNA expression significantly. Significant negative correlation between serum sFlt-1 and placental growth factor level was observed, whereas there was no significant negative correlation between sFlt-1 and VEGF. On the other hand, sTGF beta RII treatment enhanced the AdTGF beta-induced inflammation (significant elevation of SAP, TNF-alpha, and IL-12 levels and upregulation of ICAM-1 and MCP-1 mRNA expressions) and failed to prevent collagen deposition. These observations indicate that sFlt-1 gene transfer might be of therapeutic benefit in peritoneal fibrosis.     

Analysis of changes in DNA copy number in radiation-induced thymic lymphomas of susceptible C57BL/6, resistant C3H and hybrid F1 Mice

Radiation-induced thymic lymphoma in mice is a useful model for studying both the mechanism of radiation carcinogenesis and genetic susceptibility to tumor development. Using array-comparative genomic hybridization, we analyzed genome-wide changes in DNA copy numbers in radiation-induced thymic lymphomas that had developed in susceptible C57BL/6 and resistant C3H mice and their hybrids, C3B6F1 and B6C3F1 mice. Besides aberrations at known relevant genetic loci including Ikaros and Bcl11b and trisomy of chromosome 15, we identified strain-associated genomic imbalances on chromosomes 5, 10 and 16 and strain-unassociated trisomy of chromosome 14 as frequent aberrations. In addition, biallelic rearrangements at Tcrb were detected more frequently in tumors from C57BL/6 mice than in those from C3H mice, suggesting aberrant V(D)J recombination and a possible link with tumor susceptibility. The frequency and spectrum of these copy-number changes in lymphomas from C3B6F1 and B6C3F1 mice were similar to those in C57BL/6 mice. Furthermore, the loss of heterozygosity analyses of tumors in F(1) mice indicated that allelic losses at Ikaros and Bcl11b were caused primarily by multilocus deletions, whereas those at the Cdkn2a/Cdkn2b and Pten loci were due mainly to uniparental disomy. These findings provide important clues to both the mechanisms for accumulation of aberrations during radiation-induced lymphomagenesis and the different susceptibilities of C57BL/6 and C3H mice.     

Constitutive expression and induction of CYP1B1 mRNA in the mouse.

Previous studies appeared to indicate that CYP1B1 was not constitutively expressed in mouse liver. In our laboratory, we demonstrated using aromatic hydrocarbon-responsive receptor knock-out (AHR-(-)/-) mice that both piperonyl butoxide (PBO) and acenaphtyhlene (ACN) are AHR-independent inducers of murine CYP1A2 and CYP1B1 mRNA. In the current study, we demonstrate both constitutive levels and induction of CYP1B1 in mouse liver. The induction of CYP1B1 mRNA by PBO or ACN was higher in DBA/2 (Ahrd) than in C57BL/6 (Ahrb-1) mice, while 3-methylcholanthrene induced CYP1B1 more in C57BL/6 than in DBA/2 mice. These results suggest that CYP1B1 may also be induced by more than one mechanism. In addition, constitutive expression of CYP1B1 was detected in liver, kidney, and lung of untreated C57BL/6 mice. There was no gender difference in CYP1B1 expression; however, in C57BL/6 mice, the kidney contained less CYP1B1 than either liver or lung.     

The antioxidant and antifibrogenic effects of the glycosaminoglycans hyaluronic acid and chondroitin-4-sulphate in a subchronic rat model of carbon tetrachloride-induced liver fibrogenesis

Hepatic fibrosis involves the interplay of many factors including reactive oxygen species. Recent reports described antioxidant properties of glycosaminoglycans (GAGs). Since several findings have shown that hyaluronic acid (HYA) and chondroitin-4-sulphate (C4S) may act as antioxidant molecules, the aim of this research was to evaluate the antioxidant effects of HYA and C4S treatment in a rat model of liver fibrosis. The effect on tissue inhibitors of metalloproteinases (TIMPs) was also studied. Liver fibrosis was induced in rats by eight intraperitoneal injections of CCl4, twice a week for 6 weeks. HYA or C4S alone (25 mg/kg) or HYA and C4S in combination (12.5 + 12.5 mg/kg) were administered daily by the same route during the 6 weeks. At the end of the 6-week treatment period (24 h after the last dose of GAGs), the following parameters were evaluated: (1) serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, as index of hepatic cell disruption; (2) hepatic conjugated dienes (CD), as index of lipid peroxidation; (3) hepatic TIMPs activity and expression; (4) hepatic superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, as index of endogenous defences; (5) hepatic hydroxyproline, as index of collagen deposition. CCl4-induced liver fibrosis enhanced lipid peroxidation and TIMPs activation, increased ALT and AST, depleted antioxidants SOD and GPx, and caused collagen deposition in liver tissue. Treatment with GAGs, especially when in combination, successfully reduced ALT and AST rise, lipid peroxidation by evaluating conjugated dienes, TIMPs activation and mRNA expression, partially restored SOD and GPx activities, and limited collagen deposition in the hepatic tissue. The data obtained showed that these molecules were able to limit hepatic injury induced by chronic CCl4 intoxication and especially limited liver fibrosis. They also confirm that HYA and C4S may exert antioxidant mechanism, while reduction of TIMPs expression suggests that GAGs may influence MMPs and TIMPs imbalance in liver fibrosis.     

Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice

Radiation-induced lung injury (RILI) is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA) to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day). Histopathologic findings and markers of inflammation, fibrosis, and oxidative stress were compared by group. On a microscopic level, CLA inhibited macrophage influx, alveolar fibrosis, parenchymal collapse, consolidation, and epithelial cell changes. The concentration of collagen in lung tissue was lower in irradiation plus CLA mice. Radiation-induced expression of tumor necrosis factor (TNF)-α, TNF receptor 1, acetylated nuclear factor kappa B, cyclooxygenase 2, vascular cell adhesion molecule 1, and matrix metallopeptidase 9 were also attenuated by CLA. Expression levels of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1, transforming growth factor-β1, connective tissue growth factor, and type I collagen in radiation-treated lungs were also attenuated by CLA. These findings indicate that CLA ameliorates the deleterious effects of thoracic irradiation in mice by reducing pulmonary inflammation, oxidative damage, and fibrosis.     

Cytokine expression and specific lymphocyte proliferation in two strains of Cryptosporidium parvum-infected gamma-interferon knockout mice

Differences in the immune response between 2 strains of interferon-gamma knockout mice (BALB/c-GKO and C57BL/6-GKO) infected with Cryptosporidium parvum were examined because the course of infection among these 2 strains is markedly different. Infection of the BALB/c-GKO with C. parvum (2 X 10(6) oocysts/mouse) resulted in slight weight loss, oocyst shedding, and recovery from infection by 2 wk postinfection (PI). Infection with 100 oocysts in the C57BL/6-GKO mice resulted in significant weight loss, oocyst shedding, and death by day 10 PI. Splenocytes from infected mice were able to proliferate in a dose-dependent manner to soluble C. parvum-sporozoite antigen (SAg). In vitro stimulation with SAg resulted in an increase in interleukin (IL)-2, IL-4, IL-5, and tumor necrosis factor-alpha mRNA cytokine expression from splenocytes of infected BALB/cGKO mice. In contrast, only IL-5 mRNA expression was increased in the splenocytes from C. parvum-infected C57BL/6-GKO mice. Phenotypic analysis indicated no significant differences in the splenic cell populations. Previous studies indicated that susceptibility to C. parvum is dependent on CD4+ T cells and interferon-gamma production. The present study indicates that although both of these strains of knockout mice become infected with C. parvum, resolution of infection may be in part dependent on the expression of Th2 cytokines.     

PD-L1基因敲除小鼠构建及初步表型验证

目的 程序性死亡配体-1(PD-L1)是免疫调节途径的重要因子,是抗肿瘤免疫疗法中重要的靶标之一。利用CRISPR/Cas9技术成功构建PD-L1基因敲除小鼠模型,并初步分析其表型。方法 构建Cas9和sgRNA载体,并转录获得RNA,通过显微注射方式将RNA注射到C57BL/6小鼠受精卵中,经过鉴定获得F₀代阳性小鼠。F₀代小鼠与野生型C57BL/6小鼠交配获得F₁代杂合子小鼠,再通过F₁代小鼠自交获得F₂代纯合子小鼠品系。随后通过Real-Time PCR和流式实验分别检测PD-L1基因在mRNA和蛋白质水平上的表达情况。结果 Real-Time PCR和流式实验检测结果显示与野生型C57小鼠相比,PD-L1纯合子小鼠的PD-L1 mRNA相对表达水平和细胞上的蛋白质表达均有显著性下降,仅测定到本底的信号,证实已成功构建PD-L1基因敲除小鼠品系,为PD-L1体内基因功能研究提供了新的小鼠模型。     

Pivotal role of CCR1-positive leukocytes in bleomycin-induced lung fibrosis in mice

We have investigated the involvement of chemokine receptor CCR1-positive cells in bleomycin-induced lung injury, a model of pulmonary fibrosis. After bleomycin challenge in C57BL/6J mice, the expression of CCR1 mRNA increased and peaked at day 7, which paralleled to the expression of its ligands, macrophage-inflammatory protein-1 alpha and RANTES. Immunohistochemical study showed that CCR1-positive cells accumulated in the interstitial inflammatory site. Furthermore, the treatment of anti-CCR1 Ab significantly reduced the accumulation of inflammatory cells and collagen deposition, resulting in dramatic improvement of survival. These results suggest that CCR1-positive cells play significant roles in the pathogenesis of pulmonary fibrosis subsequent to bleomycin-induced lung injury, and that CCR1 could be a novel molecular target for intervention therapy against pulmonary fibrosis.     

Embryonic stem cells derived from C57BL/6J and C57BL/6N mice

Mouse embryonic stem (ES) cells with the C57BL/6 genetic background allow the generation of knockout mice without the need to backcross to C57BL/6. However, C57BL/6 ES cells whose pluripotency after homologous recombination has been confirmed are not yet available from public cell banks. To facilitate the use of ES cells derived from C57BL/6 sublines in both biologic and medical research, we demonstrated that the use of knockout serum replacement as a medium supplement and 8-cell blastomeres as recipient embryos allowed establishment of ES cells and production of germline chimeric mice, respectively. Under effective conditions, a large number of ES cell lines were established from C57BL/6J and C57BL/6N blastocysts. The majority of ES cells in many cell lines obtained from both strains showed a normal chromosome number. Germline chimeric mice were generated from C57BL/6J and C57BL/6N ES cells. Finally, the ES cell line B6J-S1UTR, derived from C57BL/6J, was used for successful production of gene knockout mice. C57BL/6J ES (B6J-S1UTR and B6J-23UTR) and C57BL/6N ES (B6N-22UTR) cells are available from the cell bank of the BioResource Center at RIKEN Tsukuba Institute (http://www.brc.riken.jp/lab/cell/english/).     

Radiation-induced pulmonary endothelial dysfunction and hydroxyproline accumulation in four strains of mice

C57BL mice exposed to 14 Gy of whole-thorax irradiation develop significant histologic lung fibrosis within 52 weeks, whereas CBA and C3H mice do not exhibit substantial fibrosis during this time. The purpose of the present study was to determine whether this strain-dependent difference in radiation histopathology is associated with genetic differences in pulmonary endothelial metabolic activity or in endothelial radioresponsiveness. C57BL/6J, C57BL/10J, CBA/J, and C3H/HeJ mice were sacrificed 12 weeks after exposure to 0 or 14 Gy of 300-kV X rays to the whole thorax. Lung angiotensin converting enzyme (ACE) activity and plasminogen activator (PLA) activity were measured as indices of pulmonary endothelial function; and lung hydroxyproline (HP) content served as an index of pulmonary fibrosis. Lung ACE and PLA activities in sham-irradiated C57BL/6J and CB57BL/10J mice were only half as high as those in sham-irradiated CBA/J and C3H/HeJ mice. Exposure to 14 Gy of X rays produced a slight but nonsignificant reduction in lung ACE and PLA activity in the C57BL strains, and a significant reduction in the CBA/J and C3H/HeJ mice. Even after 14 Gy, however, lung ACE and PLA activities in CBA/J and C3H/HeJ mice were higher than those in sham-irradiated C57BL/6J and C57BL/10J mice. Lung HP content in all four strains increased significantly after irradiation, but this increase was accompanied by an increase in lung wet weight. As a result, HP concentration (per milligram wet weight) remained constant or increased slightly in both C57BL strains and actually decreased in the CBA/J and C3H/HeJ mice. These data demonstrate significant genetic differences in both intrinsic pulmonary endothelial enzyme activity and endothelial radioresponsiveness among the four strains of mice. Specifically, strains prone to radiation-induced pulmonary fibrosis (C57BL/6J, C57BL/10J) exhibit only half as much lung ACE and PLA activity as do strains resistant to fibrosis (CBA and C3H).     

Regulatory role of gammadelta T cells in the recruitment of CD4+ and CD8+ T cells to lung and subsequent pulmonary fibrosis

The mechanisms by which T cells accumulate in the lungs of patients with pulmonary fibrosis are poorly understood. Because the lung is continually exposed to microbial agents from the environment, we repeatedly exposed C57BL/6 mice to the ubiquitous microorganism, Bacillus subtilis, to determine whether chronic exposure to an inhaled microorganism could lead to T cell accumulation in the lungs and subsequent pulmonary fibrosis. C57BL/6 mice repeatedly treated with B. subtilis for 4 consecutive weeks developed a 33-fold increase in the number of CD4+ T cells and a 354-fold increase in gammadelta T cells in the lung. The gammadelta T cells consisted almost entirely of Vgamma6/Vdelta1+ cells, a murine subset bearing an invariant TCR the function of which is still unknown. Treatment of C57BL/6 mice with heat-killed vs live B. subtilis resulted in a 2-fold increase in the number of CD4+ T cells in the lung but no expansion of gammadelta T cells indicating that gammadelta cells accumulate in response to live microorganisms. In addition, mice treated with heat-killed B. subtilis developed significantly increased pulmonary fibrosis compared with mice treated with the live microorganism. Mice deficient in Vgamma6/Vdelta1+ T cells when treated with B. subtilis had a 231-fold increase in lung CD4+ T cells and significantly increased collagen deposition compared with wild-type C57BL/6 mice, consistent with an immunoregulatory role for the Vgamma6/Vdelta1 T cell subset. These findings indicate that chronic inhalation of B. subtilis can result in T cell accumulation in the lung and fibrosis, constituting a new model of immune-mediated pulmonary fibrosis.     

Lack of adiponectin promotes formation of cholesterol gallstones in mice

Plasma adiponectin levels are reduced in obese people, and hypoadiponectinemia is recently reported to associate with cholesterol gallstone formation in human. The aim of this study was to examine the role of adiponectin in gallstone formation using adiponectin knockout mice. We analyzed male knockout and C57BL6J mice fed normal or lithogenic diet for 6 weeks. On lithogenic diet, the prevalence rate of gallstone was significantly greater in knockout mice than C57BL6J mice. The molar percentages of β and ω-muricholic acid were significantly higher and hepatic sterol 12α-hydroxylase expression (cyp8b1) was significantly lower in knockout mice than C57BL6J mice fed normal diet. The bile apolipoprotein A-I protein levels were decreased in knockout mice. Histological examination showed gallbladder wall thickening and accumulation of glycoprotein in the gallbladder of knockout mice. Gallbladder phospholipase A2-IVA expression was significantly higher in knockout mice than in C57BL6J mice fed lithogenic diet. Our results indicate that lack of adiponectin promotes gallstone formation in mice.     

Unexpected Rescue of Alpha-synuclein and Multimerin1 Deletion in C57BL/6JOlaHsd Mice by Beta-adducin Knockout

Uniform genetic background of inbred mouse strains is essential in experiments with genetically modified mice. In order to assess Add2 (beta-adducin) function, its null mutation was produced in embryonic stem cells derived from 129Sv mouse and the subsequently obtained mouse mutants were backcrossed for 6 generations with C57BL/6JOlaHsd strain. Comparison of brain proteins between mutated and control animals by two-dimensional gels linked to mass spectroscopy analysis showed expression of Snca (alpha-synuclein) in the mutated animals, but unexpectedly not in the control C57BL/6JOlaHsd mice. Comparison between C57BL/6JOlaHsd and C57BL/6NCrl mice confirmed the presence of a deletion encompassing Snca and in addition Mmrn1 (multimerin1) loci in C57BL/6JOlaHsd strain. The segregation of mutated Add2 together with an adjacent part of the chromosome 6 derived from 129Sv mice, rescued the loss of these two genes in knockout mice on C57BL/6JOlaHsd background. The fact that Add2 knockout was compared with the C57BL/6JOlaHsd mouse strain, which is actually a double knockout of Snca and Mmrn1 emphasizes a need for information provided by commercial suppliers and of exact denominations of substrains used in research.     

Influence of interleukin-2 and interferon-gamma in murine schistosomiasis

Schistosoma mansoni-infected mice were administered at the time of parasite residency in the lung with recombinant murine interleukin (IL)-2 or interferon-gamma (IFN-gamma), to evaluate the impact of cytokines in host responses to primary schistosomiasis. S. mansoni lung-stage schistosomula did not affect plasma lipids levels in BALB/c, while elicited significant (p<0.05) increase in free fatty acids (FA) and decrease in cholesterol plasma levels in C57BL/6 and CD1 mice, and stimulated expression of mRNA for Th2 cytokines in BALB/c and Th1 cytokines in C57BL/6 and CD1 mice. Production of specific antibodies was negligible in the 3 strains. Interleukin-2 treatment elicited significant (p<0.001) decrease in triglycerides (TG) in CD1, and decrease in TG and cholesterol plasma levels and down-regulation of TNF-alpha mRNA expression in C57BL/6 mice. Induction of type 2 cytokines and/or IFN-gamma mRNA expression did not lead to increase in percentage of specific antibody responders in any mouse strain. Exogenous IL-2-related reduction in cholesterol plasma levels and TNF-alpha mRNA expression in C57BL/6 mice was associated with significant (p<0.05) decrease in adult worm recovery and egg count. Treatment with IFN-gamma elicited significant (p<0.05) free FA plasma levels increase in BALB/c and C57BL/6 and decrease in CD1 mice. Expression of type 2 cytokines mRNA was stimulated in BALB/c and CD1 mice, yet was not accompanied with increase in humoral responses. Exogenous IFN-gamma-related reduction in free FA plasma levels and IFN-gamma mRNA response, and up-regulation of TNF-alpha mRNA expression in CD1 mice were associated with significant increase in adult worm burden and egg load. The data were discussed in an attempt to define host factors predictive of resistance to schistosome infection.