Choosing a Reduced-Intensity Conditioning Regimen for Allogeneic Stem Cell Transplantation,Fludarabine/Busulfan versus Fludarabine Melphalan: A Systematic Review and Meta-Analysis

Fludarabine with busulfan (FB) or melphalan (FM) are 2 more commonly used reduced-intensity conditioning (RIC) regimens for allogeneic stem cell transplantation (HCT).We present a systematic review and meta-analysis of studies comparing these 2 RIC regimens. We searched electronic databases from inception through November 1, 2017 for literature searches to identify relevant studies. A DerSimonian random effects model was used to measure efficacy outcomes; hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) are reported. Seven studies, including a total of 1955 patients, met criteria for inclusion, of which 6 were included in the overall pooled analysis because of repetition of some patients in 2 studies. Three studies were included in the subgroup analysis of acute myelogenous leukemia (AML)/myelodysplastic syndrome (MDS) and 2 in the subgroup analysis of lymphoid malignancies. Overall survival (OS) and progression-free survival were not statistically significantly different between the 2 RIC regimens in analysis of all studies. However, OS was better with FM in subgroup analysis of AML/MDS studies (HR, .83; 95% CI, .73 to .95). Nonrelapse mortality was lower with FB (HR, .64; 95% CI, .46 to .89), whereas relapse was lower with FM (HR, 1.52; 95% CI, 1.13 to 2.06) in the analysis of all studies. This meta-analysis shows that FB and FM are associated with a similar OS in patients undergoing HCT. Relapse rates are lower with FM but at the cost of higher nonrelapse mortality.     

Lactoferrin can protect mice against a lethal dose of Escherichia coli in experimental infection in vivo

Experiments were undertaken to demonstrate and partially explain the protective effect of bovine lactoferrin (LB) when administered intravenously to mice 24 h before a challenge with a lethal dose of Escherichia coli. About 70% of mice pretreated with LB survived challenge. The survival rates in control mice treated with E. coli alone and pretreated with bovine serum albumin (BSA), were 4 and 8%, respectively. Human lactoferrin (LH) had almost the same protective effect as LB. Sufficient amounts of ferric ions were given to mice, in single and multiple doses, for full serum transferrin saturation 30 min before or after E. coli administration. The multiple dose of ferric ions did not change considerably the survival rate of mice pretreated with LB. In contrast, a single dose of ferric ions gradually decreased the survival rate of the mice after the first week of experiment. From day 14 this decrease was statistically significant in all groups of mice treated with a single dose of ferric ions when compared with mice pretreated only with LB, and the difference ranged from 25 to 35% on day 30. The possible mechanism(s) of protective effect of LB and role of iron ions are discussed.     

Lactoferrin can protect mice against a lethal dose of Escherichia coli in experimental infection in vivo.

Experiments were undertaken to demonstrate and partially explain the protective effect of bovine lactoferrin (LB) when administered intravenously to mice 24 h before a challenge with a lethal dose of Escherichia coli. About 70% of mice pretreated with LB survived challenge. The survival rates in control mice treated with E. coli alone and pretreated with bovine serum albumin (BSA), were 4 and 8%, respectively. Human lactoferrin (LH) had almost the same protective effect as LB. Sufficient amounts of ferric ions were given to mice, in single and multiple doses, for full serum transferrin saturation 30 min before or after E. coli administration. The multiple dose of ferric ions did not change considerably the survival rate of mice pretreated with LB. In contrast, a single dose of ferric ions gradually decreased the survival rate of the mice after the first week of experiment. From day 14 this decrease was statistically significant in all groups of mice treated with a single dose of ferric ions when compared with mice pretreated only with LB, and the difference ranged from 25 to 35% on day 30. The possible mechanism(s) of protective effect of LB and role of iron ions are discussed.     

Role of natural killer cells in resistance to Cryptococcus neoformans infections in mice.

Previous studies have suggested a possible role for natural killer (NK) cells in resistance to some fungal infections, including Cryptococcus neoformans infections. The role of NK cells in early clearance of C neoformans from tissues and in long-term survival was studied in mice following intravenous inoculations of the organism. Mice treated with anti-asialo GM1 antiserum to temporarily reduce NK activity demonstrated an increase in colony-forming units (CFU) of C neoformans in the lung 24 hours after an intravenous inoculation of the organism. CFU in liver, spleen, kidney, and brain were not different in anti-asialo GM1 antiserum-treated versus control mice. An NK-specific reagent, anti-NK 1.1 monoclonal antibody, was used to deplete mice of NK cells in vivo for at least 14 days without affecting other natural defenses. The number of C neoformans retained in the lungs 24 hours after inoculation of the organism was significantly greater in NK cell-depleted mice than in controls, although CFU in other organs were unaffected. Following the intravenous inoculation of C neoformans, the survival of anti-NK 1.1-treated mice was not different from control mice. The effect of NK cell activity on resistance to C neoformans was also determined after an intratracheal inoculation of the organism. Mice pretreated with anti-NK 1.1 demonstrated no increases in CFU in the lungs, spleen, or brain as compared with controls. These data indicate that NK cells can play a role in vivo in early resistance against C neoformans if the organism is delivered via the intravenous route. However, NK cells do not play a role in either determining survival after an intravenous inoculation nor in resistance during an infection acquired via the respiratory tract.     

Prophylactic administration of interleukin-2 protects mice from lethal challenge with gram-negative bacteria.

Prophylactic administration of recombinant human interleukin-2 (IL-2) in mice enhanced survival and produced complete recovery from an otherwise lethal acute bacterial infection. IL-2 was administered as a single intraperitoneal or intravenous bolus dose to CDI mice 18 h before challenge with a lethal dose of a clinical isolate of Escherichia coli type O2 (minimal 100% lethal dose, 6 X 10(7) CFU per mouse). At IL-2 dosages of 7 X 10(6) U/kg, 90% of treated CDI mice survived as compared to 0% for the excipient buffer control animals (P less than 0.001). This protective effect was also demonstrable in immune-deficient beige mice. The IL-2 effect was dose dependent; protection was consistently observed in mice pretreated with IL-2 at doses ranging from 1.8 X 10(6) to 7 X 10(6) U/kg. However, at 3.5 X 10(5) U/kg the protective effect was more variable. The route of administration of IL-2 was shown to play an important role; when IL-2 and challenge bacteria were given by the same route (either intravenously or intraperitoneally), protection was readily observable, but when IL-2 and challenge bacteria were given by different routes, little or no protective effect was observed. The protective effect was fully inducible as early as 1 h after IL-2 administration and was effective against various strains of gram-negative bacteria, indicating that the probable mode of action represents control of the establishment of infection by increased activity of the nonspecific host defense mechanisms. The IL-2 effect was abrogated by the administration of carrageenan, suggesting a possible role of macrophages. These data demonstrate that IL-2 may be a potentially useful adjunct for the prophylaxis of bacterial infections in both clinical and veterinary medicine.     

Intravenous Busulfan Compared with Treosulfan-Based Conditioning for Allogeneic Stem Cell Transplantation in Acute Myeloid Leukemia: A Study on Behalf of the Acute Leukemia Working Party of European Society for Blood and Marrow Transplantation

Dose intensity of the conditioning regimen has significant impact on the outcomes after stem cell transplantation (SCT) for acute myeloid leukemia. Most studies have shown more relapse, less nonrelapse mortality (NRM), and similar overall survival after reduced-intensity and myeloablative conditioning. There are limited data on the dose equivalence and expected outcomes of treosulfan-based compared with busulfan-based conditioning. We compared SCT outcomes after fludarabine with either intravenous busulfan at a myeloablative dose (FB4, 12.8?mg/kg, n?=?1265) or a reduced dose (FB2, 6.4?mg/kg, n?=?1456) or treosulfan at 42 g/m² (FT14, n?=?403) or 36 g/m² (FT12, n?=?168). Median patient age was 48, 60, 57, and 60 years in the FB4, FB2, FT14, and FT12 groups, respectively (P?<?.0001). Two-year overall survival was 58%, 53%, 53%, and 51%, respectively (P?=?.25). Multivariate analysis identified advanced age, advanced disease status, and secondary leukemia to be associated with worse survival. Relapse rate was 30%, 35%, 34%, and 40%, respectively. Relapse was more common after FB2, advanced age and disease status, secondary leukemia, and sibling donors. NRM was 17%, 18%, 21%, and 16%, respectively. NRM was least common after FT12 and more common with advanced age and disease status and unrelated donors. Treosulfan-based regimens were associated with lower rates of graft-versus-host disease. There was no difference in any outcome among patients in first complete remission at transplantation. However, there was better survival with treosulfan-based conditioning in advanced leukemia. In conclusion, survival is determined mostly by disease biology and is similar after various regimens. Treosulfan-based conditioning is more similar to myeloablative than to reduced-intensity conditioning but can be administered safely in older patients, with lower rates of graft-versus-host disease and possibly better outcomes in patients with active leukemia.     

Reduced resistance to Pseudomonas septicaemia in diabetic mice.

Antibacterial resistance in a diabetic state was studied using experimental Pseudomonas infection in streptozotocin (SZ) induced diabetic mice. The results obtained were as follows: (1) there was no difference in acute death rate between normal and diabetic mice when infected with Pseudomonas aeruginosa. However, a significant increase in the number of bacteria in the kidney and liver occurred at a later stage of infection in diabetic mice. (2) Active immunization with a phenolized vaccine resulted in 100% survival in either normal or diabetic mice; otherwise challenge was lethal. However, the organs examined in diabetic vaccinated mice contained distinctly increased numbers of bacteria as compared with normal vaccinated mice 7 days after infection. (3) There were no significant differences in antibody titre between normal and diabetic ice after infection, but passive protection with immune serum from diabetic vaccinated mice was less effective than that from vaccinated mice. Furthermore, immune serum from normal vaccinated mice exerted protective action less efficiently in diabetic recipients than in normal recipients. (4) The bactericidal effect of peripheral whole blood was apparently lower in diabetic mice than in normal mice. (5) Treatment with insulin restored such reduced resistance to Pseudomonas infection in diabetic mice. These findings suggest that the decreased resistance to Pseudomonas infection in diabetic mice should be ascribed to impaired function of antibody, abnormalities in phagocytic cells and disturbed microcirculation caused by the insulin-deficient state.     

Protection against lethal bacterial infection in mice by monocyte-chemotactic and -activating factor.

Chemotactic factors regulate the recruitment of neutrophils, lymphocytes, or monocytes-macrophages to infectious and inflammatory sites. The purpose of this study was to determine whether monocyte-chemotactic and -activating factor (MCAF [MCP-1], a JE gene product) also influences the host defense mechanism against microbial infection. We evaluated the effect of recombinant human MCAF on the survival rate of mice systemically infected with Pseudomonas aeruginosa or Salmonella typhimurium. The administration of 2.5 micrograms of MCAF 6 h before infection completely protected the mice from lethal infection. Mice with cyclophosphamide-induced leukopenia exhibiting increased susceptibility to P. aeruginosa were also endowed with resistance by the same dose of MCAF. Administration of MCAF at -6 h was critical, since MCAF given either earlier or later than -6 h failed to rescue mice from lethal infection. The in vivo effect on the survival of mice paralleled the reduced recovery of viable P. aeruginosa or S. typhimurium from the peritoneal cavity, i.e., the number of recovered bacteria from the MCAF (2.5 micrograms per mouse)-treated mice was reduced to less than 2% of control mice for P. aeruginosa and 4% of control mice for S. typhimurium at 24 h. Since MCAF exhibited chemotaxis on murine macrophages as well as enhanced phagocytosis and killing of bacteria in vitro, the activation of macrophages, followed by the recruitment into the peritoneal cavity, is responsible for eliminating bacteria and thus enhancing the survival rate.     

Lipopolysaccharide-induced non-specific resistance to systemic Escherichia coli infection in mice

A high degree of non-specific resistance to a lethal systemic Escherichia coli infection was induced in mice by pretreatment with a small dose (less than 5 micrograms/mouse) of the homologous lipopolysaccharide (LPS) or with heterologous rough-type LPS from E. coli K-12. The route of LPS administration, intraperitoneally or subcutaneously, did not influence the development of resistance, suggesting that a systemic cell activation was responsible for the effect. The enhanced elimination of bacteria was similar to that in mice recovering from a sublethal E. coli infection. In the LPS-treated mice, elimination of the challenge bacteria from the peritoneal cavity and the blood started 3-4 h after challenge whereas, in controls, the bacterial numbers continued to increase until the mice died. The detoxified LPS derivative, monophosphoryl lipid A (MPL), also increased the survival of mice infected with E. coli O18:K1. However, the dose of MPL required for optimal infection resistance was 100-fold greater than that of native, E. coli K-12 LPS, corresponding to the 100-fold reduced toxicity of MPL for mice and rabbits in lethality and pyrogenicity assays.     

Expression of a complete and functional complement system by human neuronal cells in vitro

We demonstrate in vitro expression of complement components, i.e. C3, factor H (FH), factor B (FB), C4, C1-inhibitor (C1-inh), C1q, C5, C6, C7 and C9, by four human neuroblastoma cell lines IMR32, SKNSH, SH-SY5Y and KELLY. Activating proteins C4, C9 and C1q, and regulatory proteins FH and C1-inh were produced constitutively by the four cell lines. C3, C6 and FB were mainly produced by SKNSH and SH-SY5Y. Western blot experiments showed that secreted proteins were structurally similar to their serum counterparts. An additional polypeptide of 43 kDa with FH immunoreactivity was detected, which could correspond to the N-terminal truncated form found in plasma. Regulation of complement expression by inflammatory cytokines, lipopolysaccharide and dexamethasone was tested in vitro. These factors had no significant effects on activating synthesis of components C3, FB and C4, but expression of regulating components C1-inh and FH was strongly increased particularly by IFN-gamma and tumor necrosis factor-alpha. The rate of synthesis of complement components was dependent on the differentiation of neuroblastoma cells. This effect of differentiation was also observed on normal rat neurons. Rat cerebellar granule cells constitutively expressed mRNA for C4 and C1q, but expression of C3 mRNA was induced by differentiation. This study shows that neurons could be another local source of complement in the brain, besides astrocytes and microglia. Human neuroblastoma cell lines can constitute an interesting model to analyze complement biosynthesis by human neurons. Local complement expression by neurons in vivo may be implicated in some physio-pathological processes.     

Synergistic effect on mortality in mice with murine cytomegalovirus and Pseudomonas aeruginosa, Staphylococcus aureus, or Candida albicans infections.

A synergistic effect on mortality was demonstrated in a combined infection of mice with murine cytomegalovirus (MCMV) and Pseudomonas aeruginosa, Staphylococcus aureus, or Candida albicans. Mice infected intraperitoneally with a 0 to 20% lethal dose inoculum of MCMV 3 days prior to the intravenous injection of a 0 to 20% lethal dose inoculum of either the bacteria or fungus demonstrated a striking enhancement of mortality. MCMV-infected mice given Pseudomonas or Staphylococcus exhibited a 90 to 100% mortality within 24 to 48 h, whereas 80% of viral-infected animals injected with Candida died in 5 days. Injection of the bacteria or fungus at various times during the MCMV infection resulted in enhanced mortality on days 0,1,2, and 3 of the viral infection. Greatest synergism was observed on day 3, with a progressive decline in death rates thereafter. Immunization with MCMV abrogated the synergistic effect on mortality in all three combined infections. Immunization with Pseudomonas reduced mortality in the combined MCMV-Pseudomonas infection. These results indicate that mice exhibit a markedly enhanced susceptibility to bacterial and fungal infections during the course of the MCMV infection and suggest that the enhancement may be related to viral-induced alterations in host resistance.     

Antimicrobial resistance in recent fecal enterococci from healthy volunteers and food handlers in Spain: genes and phenotypes

Susceptibility patterns to 15 different antibiotics and the presence of resistance genes were evaluated in recent fecal Enterococcus isolates recovered from 42 healthy volunteers (HV) and 43 food-handlers (FH). A total of 142 Enterococcus faecalis, 74 Enterococcus faecium, and 23 Enterococcus spp. with different antibiotic susceptibility patterns were studied. A higher percentage of resistance for moxifloxacin, erythromycin, glycopeptides and high-level resistance (HLR) to gentamicin were observed in the FH group. Ampicillin- or linezolid-resistant isolates were not recovered in any of the groups. The tet(M) gene was found in 96% and in 85% of tetracycline-resistant isolates from HV and FH, respectively. HLR-kanamycin was mediated by aph(3')-IIIa, or aac(6')-aph(2"), or both genes in all isolates from HV group and in 86% from FH group. The aac(6')-aph(2") gene was found in all HLR-gentamicin isolates. Ninety-one percent of HV and 71% of FH erythromycin-resistant isolates harbored the erm(B) gene (erythromycin MIC range of 8-128 microg/ml), whereas erm(A), erm(C), or mef(A) genes were not detected. Coexistence of erm(B), aph(3')-IIIa, and tet(M) genes was observed in 17% of the isolates of both groups. The HLR-gentamicin isolates presented unrelated PFGE patterns while 2 out of 3 vanA E. faecium isolates showed an indistinguishable SmaI-pulsed-field gel electrophoresis (PFGE) pattern. This study shows that despite 4 years of official banning of antibiotic growth promoters in animals, enterococci isolated from FH are more resistant than those from HV. This suggests the permanence of resistant clones or transferable resistance elements in farms and a possible exchange between food products and humans, or eventually the long-term permanence of certain clones in the FH intestinal tract.     

Phage lytic enzyme Cpl-1 as a novel antimicrobial for pneumococcal bacteremia

Streptococcus pneumoniae is becoming increasingly antibiotic resistant worldwide, and thus new antimicrobials are badly needed. We report the use of Cpl-1, the lytic enzyme of a pneumococcal bacteriophage, as an intravenous therapy for pneumococcal bacteremia in a mouse model. A 2000- microg dose of Cpl-1 reduced pneumococcal titers from a median of log(10) 4.70 CFU/ml to undetectable levels (相似文献   

Simple, efficient and successful vitrification of bovine blastocysts using electron microscope grids.

This study demonstrates that higher survival of vitrified-thawed bovine blastocysts can be obtained using electron microscope (EM) grids as embryo containers at freezing, rather than plastic straws. In-vitro produced day 7 bovine blastocysts after in-vitro fertilization (IVF) were vitrified on grids or in straws with EFS40 freezing solution and their survival after thawing was compared. Embryo survival was assessed as re-expanded and hatched rates at 24 and 48 h after thawing respectively. When the effects of exposure to vitrification solution and chilling injury from the freezing procedure were examined, embryo survival in the exposure group (24 h: 100, 48 h: 73.3%) was not different compared with that in the control group (100, 84.4%). After vitrification, the hatched rate of the EM grid group 48 h after thawing (67.8%) was significantly higher than that of the straw group (53.3%) (P < 0.05). Fast developing embryos (expanded blastocyst and early hatching blastocyst stage) showed better resistance to freezing than delayed ones (early blastocyst stage), irrespective of embryo containers (early: 24 h, 57.1 and 48 h, 24.4%; expanded: 84.7 and 60.6%; early hatching: 91.7 and 80.0%) (P < 0.001). When using expanded and early hatching blastocysts, embryo survival rates in the vitrification-EM grid group (67.8, 95.0% respectively) were significantly higher than that of the vitrification-straw group (53.0, 65.0%) at 48 h.     

Trehalose dimycolate enhances resistance to infection in neutropenic animals.

Bacterial infections are lethal complications of neutropenia, and antibiotics alone are inadequate therapy for these infections. Irradiated mice become severely neutropenic and remain susceptible to infection for 2 to 3 weeks, depending on the dose and quality of radiation. Some bacterial cell wall derivatives stimulate nonspecific host defense mechanisms against a variety of microbes which might cause postirradiation infection. In this study we determined if the cell wall glycolipid trehalose dimycolate (TDM), derived from Mycobacterium phlei, or a synthetic preparation of TDM was able to (i) enhance survival in mice when given before or after lethal doses of 60Co radiation and (ii) increase nonspecific resistance to postirradiation infection. Treatment with TDM oil-in-water emulsions and with synthetic TDM significantly enhanced survival before and after lethal doses of 60Co irradiation. This result correlated with the ability of TDM to reduce the translocation of intestinal bacteria and to stimulate hematopoiesis. With respect to nonspecific resistance to infection, TDM injected 1 h after sublethal irradiation increased resistance to a lethal Klebsiella pneumoniae challenge (10 50% lethal doses of K. pneumoniae in 30 days [LD50/30]) 4 or 14 days later. Increasing the dose of K. pneumoniae to 5,000 LD50/30 on day 4 overwhelmed the ability of TDM-treated mice to overcome infection. However, TDM treatment 1 h postirradiation combined with ceftriaxone antibiotic therapy (days 5 through 14) enhanced survival, even when the higher dose of bacteria (5,000 LD50/30) was used. These results indicate that in irradiated mice, TDM can be used to enhance survival and, as a potent stimulant of nonspecific resistance to infection in neutropenic mice, can act synergistically with antibiotic therapy to reduce sepsis and mortality.     

Modification of post-operative C. albicans sepsis by glucan immunostimulation

Glucan, a beta-1,3 polyglucose, was evaluated for its ability to enhance resistance of post-operative mice to experimentally induced C. albicans sepsis. Male C57BL/6J mice were injected i.v. with glucan (0.45 mg/mouse) on days 10,7,4 and 1 prior to midline laparotomy and intravenous challenge with 3 X 10(6) C. albicans. The detrimental effect of surgery on survival following C. albicans infection was manifested by a 47% survival in the non-surgery-infected group in contrast to 20% in the surgery-infected group. Protection against C. albicans was observed in the glucan-treated groups. The glucan-treated non-operated mice manifested 100% survival while the surgery group had a 73% survival. Glucan significantly enhanced macrophage phagocytic function in control and operated mice. Laparotomy alone did not significantly depress macrophage phagocytosis. Histopathological studies revealed that glucan markedly inhibited the renal pathology associated with C. albicans challenge both in the presence and absence of laparotomy. These data indicate that glucan increased survival and reduced renal pathology associated with C. albicans challenge in the post-operative period. These observations suggest that Biologic Response Modifiers such as glucan may be effectively employed in patients who are at risk for post-operative infections.     

The requirement for gamma interferon in resistance of mice to experimental tularemia

The role of gamma interferon (IFN-gamma) in the host response to experimental tularemia was evaluated in a murine model. C57BL/6 strain mice were given a series of daily intravenous injections of 10(6) units (U) recombinant murine IFN-gamma prior to infection with Francisella tularensis LVS. Three days later, the number of bacteria in the tissues of IFN-gamma-treated mice was found to be less than that in control mice by a factor of 10-20. The effect of IFN-gamma on anti-tularemic resistance was dependent upon the administered dose, with as little as 10(4) U/mouse/day inducing a significant level of enhanced resistance. IFN-gamma was also effective in enhancing resistance to tularemia in the A/J mouse strain which, in comparison with the C57BL/6 strain, is more susceptible to infection. When C57BL/6 mice were treated with a monoclonal antibody directed against murine IFN-gamma, the number of Francisella recovered from their tissues 6 days following infection was increased by as much as 15 times, in comparison with control mice. The results of these experiments clearly indicate that the resolution of experimental murine tularemia is dependent, at least in part, on the participation of IFN-gamma.     

Acquisition of regulators of complement activation by Streptococcus pyogenes serotype M1

Opsonization of bacteria by complement proteins is an important component of the immune response. The pathogenic bacterium Streptococcus pyogenes has evolved multiple mechanisms for the evasion of complement-mediated opsonization. One mechanism involves the binding of human regulators of complement activation such as factor H (FH) and FH-like protein 1 (FHL-1). Acquisition of these regulatory proteins can limit deposition of the opsonin C3b on bacteria, thus decreasing the pathogen's susceptibility to phagocytosis. Binding of complement regulatory proteins by S. pyogenes has previously been attributed to the streptococcal M and M-like proteins. Here, we report that the S. pyogenes cell surface protein Fba can mediate binding of FH and FHL-1. We constructed mutant derivatives of S. pyogenes that lack Fba, M1 protein, or both proteins and assayed the strains for FH binding, susceptibility to phagocytosis, and C3 deposition. Fba expression was found to be sufficient for binding of purified FH as well as for binding of FH and FHL-1 from human plasma. Plasma adsorption experiments also revealed that M1(+) Fba(+) streptococci preferentially bind FHL-1, whereas M1(-) Fba(+) streptococci have similar affinities for FH and FHL-1. Fba was found to contribute to the survival of streptococci incubated with human blood and to inhibit C3 deposition on bacterial cells. Streptococci harvested from log-phase cultures readily bound FH, but binding was greatly reduced for bacteria obtained from stationary-phase cultures. Bacteria cultured in the presence of the protease inhibitor E64 maintained FH binding activity in stationary phase, suggesting that Fba is removed from the cell surface via proteolysis. Western analyses confirmed that E64 stabilizes cell surface expression of Fba. These data indicate that Fba is an antiopsonic, antiphagocytic protein that may be regulated by cell surface proteolysis.     

Deletion of IFN-gamma reduces fumonisin-induced hepatotoxicity in mice via alterations in inflammatory cytokines and apoptotic factors.

Fumonisin B(1) (FB(1)) produces species-specific and organ-specific toxicity, including equine leukoencephalomalacia, porcine pulmonary edema, and hepatic or renal damage in other animals. FB(1) causes inhibition of ceramide synthase, leading to accumulation of free sphingoid bases. We previously reported that such cytokines as tumor necrosis factor-alpha (TNF-alpha) modify FB(1)-induced hepatic apoptosis in male mice. FB(1) also caused induction of interferon-gamma (IFN-gamma) in mouse liver, and, therefore, it was worthwhile to determine the role IFN-gamma plays in FB(1) toxicity. In the current study, male IFN-gamma-knockout (GKO) mice and their wild-type (WT) counterparts, C57BL/6J, were treated subcutaneously (s.c.) with 2.25 mg/kg/day of FB(1) for 5 days and sampled 1 day after the last injection. The levels of circulating liver enzymes were increased in WT animals but considerably less in GKO mice. Reduced hepatotoxicity in GKO mice was evident by histologic evaluation and enumeration of apoptotic cells. The induction of TNF-alpha and interleukin-12 (IL-12) p40 by FB(1) in liver was less in GKO mice compared with WT animals. The GKO mice also had a reduced accumulation of liver sphinganine than did WT mice after FB(1) treatment. Results suggested the implication of IFN-gamma in FB(1)-induced hepatotoxicity, which can be explained by a lack of TNF-alpha and IL-12 amplification in the liver of the GKO mice. In addition, the GKO mice had altered expression of various apoptotic and antiapoptotic factors in liver. These changes were accompanied by a greater number of proliferating cells in the liver of GKO mice after FB(1) treatment, which may also contribute to the reduced hepatotoxicity of FB(1) in GKO mice. Whereas the GKO mice show reduced sensitivity to FB(1) and FB(1) treatment elevates IFN-gamma expression, decreased hepatotoxicity to FB(1) could result from alterations in sphingolipid metabolism in the GKO strain.