Bone marrow cell response following induction of acute inflammation in different strains of mice

The magnitude of the macrophage inflammatory response differs among inbred mouse strains. Mice of the A/J strain respond poorly to sterile inflammatory stimuli while those of the C57BL/6 strain show a strong response. Inflammatory macrophages found at the site of inflammation are the product of bone marrow (BM) myeloid stem cells. Mice of the A/J strain were found to have half the number of BM nucleated cells per femur than those of the C57BL/6 strain. The lower BM cellularity may be one reason for the poor macrophage inflammatory response observed in A/J mouse strain. Using A x B/B x A recombinant inbred mouse strains, we determined that the number of nucleated cells per femur found in normal mice was not a determining factor of the magnitude of the macrophage inflammatory response. One additional explanation for the poor macrophage inflammatory response in mice of the A/J strain is their deficiency in the C5 component of complement. Using a C5-sufficient A/J.C5 congenic strain, we have previously shown that the presence of C5 on the A/J background improved their inflammatory response. We compared A/J and A/J.C5 mouse strains to determine whether or not C5 had an impact on the BM cell response to inflammatory stimulus. The presence of C5 on the A/J background could contribute to the improvement of the inflammatory response in mice of the A/J.C5 strain by inducing a greater number of nucleated cells to exit the BM compartment early following induction of inflammation.     

Severity-of-illness scores for neutropenic cancer patients in an intensive care unit: Which is the best predictor? Do multiple assessment times improve the predictive value?

C57BL/6 mice genetically deficient in interleukin-5 (IL-5-/-) and normal C57BL/6 (IL-5+/+) mice were infected with larvae of a homogonic strain of the nematode Strongyloides ratti. In primary infections both male and female IL-5-/- mice released two to four times more eggs and larvae than IL-5+/+ mice. IL-5-/- mice harboured about 60% more intestinal worms, which were more fecund, than IL-5+/+ mice. The duration of the infection was similar in normal and IL-5-deficient mice. Both IL-5-/- and IL-5+/+ mice resisted a secondary infection. IL5-/- mice lost more weight during the infection than normal mice and took longer to regain their initial weight after expelling the worms. The number of eosinophils increased in the bone marrow, peritoneal cavity and small intestine of IL-5+/+ mice, but not IL-5-/- mice, following infection. No significant differences between infected IL-5+/+ and IL-5-/- mice in mast cells or other leucocytes were observed in the peritoneal cavity. Thus, IL-5 functions to protect the host in a primary infection of S. ratti by limiting the number and fecundity of worms establishing in the small intestine. This protection is correlated with elevated blood and tissue eosinophilia which occurs in normal mice but not in IL-5-/- mice.     

Strain difference in the induction of T-cell activation-associated, interferon gamma-dependent hepatic injury in mice

A single intravenous injection of concanavalin A (Con A) induces T-cell activation-associated inflammatory injury selectively in the liver. This study investigated the strain difference in the development of Con A-induced hepatic injury. Normal C57BL/6 and BALB/c spleen cells produced comparable levels of T-cell-derived lymphokines (interferon gamma [IFN-gamma], tumor necrosis factor alpha [TNF-alpha], and interleukin-2 [IL-2]) following in vitro stimulation with Con A. A single intravenous injection of Con A to C57BL/6 mice induced the plasma levels of TNF-alpha and IL-2 comparable with or slightly higher than those observed in BALB/c mice, whereas the same treatment resulted in an apparently lower level of IFN-gamma production in C57BL/6 mice. RNA from livers of Con A-treated C57BL/6 mice exhibited lower levels of IFN-gamma mRNA than RNA of BALB/c livers. Unexpectedly, a dramatic difference in the severity of hepatic injury was observed between C57BL/6 and BALB/c. Namely, the peak alanine transaminase (ALT) level was more than 15,000 U/L and inducible as early as 8 hours after injection of 0.2 mg Con A per mouse in the C57BL/6 strain, whereas the peak was approximately 3,000 U/L and induced as late as 24 hours after Con A injection in the BALB/c strain. The increase in plasma ALT levels was limited to less than 10% by injection of anti-IFN-gamma monoclonal antibody (mAb) in both strains. The C57BL/6 strain inducing lower levels of IFN-gamma exhibited higher IFN-gamma responsiveness as exemplified by the intrahepatic expression of an IFN-gamma-inducible gene, an inducible type of nitric oxide (NO) synthase (iNOS). These results indicate that, while IFN-gamma produced in vivo by activated T cells induces hepatic injury, there exists a striking strain difference in the induction of IFN-gamma-dependent hepatic injury.     

The full expression of the ity phenotype in ityr mice requires C3 activation by Salmonella lipopolysaccharide

Our previous study has shown that the rapid and sufficient activation of complement by Salmonella lipopolysaccharide occurs in genetically resistant (Ityr) A/J mice. To assess whether the level of complement activation by a virulent strain of Salmonella typhimurium regulates the level of murine natural resistance, we compared levels of serum complement activation by S. typhimurium and kinetics of serum-opsonized S. typhimurium grown in macrophages using several strains of resistant (Ityr) and susceptible (Itys) mice. Itys macrophages killed intracellular S. typhimurium to the same extent as did Ityr macrophages when the pathogen was opsonized with Ityr serum. Opsonization of S. typhimurium with Itys serum reduced intracellular killing activity in Ityr macrophages to the same level as seen with Itys macrophages. Incubation of S. typhimurium with 25% Mg2+ EGTA (5 mm MgCl2-3 mm ethylene glycol-bis (beta-aminotheyl either)-N,N,N',N'-tetraacetic acid)-chelated Ityr serum resulted in higher levels of C3 deposition onto the surface of this bacteria, C3b generation and also C3 consumption, compared with that with Mg2+ EGTA-chelated Itys serum. Opsonization of S. typhimurium with A/J serum prior to infection increased early resistance in Itys mice. Infection with a virulent strain of S. typhimurium induced the expression of interleukin-10 (IL-10) mRNA at higher levels in C57BL/6 mice than in A/J mice. However, opsonization of S. typhimurium with A/J serum decreased bacterial growth in the spleen of C57BL/6 mice to the same level as observed for A/J mice in association with decreased expression levels of IL-10 mRNA. Moreover, administration of anti-C3 antibodies reduced the resistance of A/J mice in association with a decrease in serum levels of C3. These results indicate that the high level of complement activation via the alternative pathway in Ityr serum by a virulent strain of S. typhimurium reduces the virulence of this pathogen, which may contribute to the full expression of Ity phenotype in Ityr mice.     

Th1 response in Salmonella typhimurium-infected mice with a high or low rate of bacterial clearance

Previous studies have shown that the capacity to clear an attenuated strain of Salmonella typhimurium after the second week of infection varies widely among mouse strains. Bacterial clearance is mediated by CD4+ T cells and is regulated in part by the H-2 complex. The aim of the present study was to compare the patterns of cytokine mRNA expression in the spleens of C57BL/6 (H-2b) and CBA (H-2k) mice, which exhibit a low and a high rate of bacterial clearance, respectively. A transient increase in interleukin-12 (IL-12) mRNA levels was found in both mouse strains. Gamma interferon (IFN-gamma) gene expression was higher and more sustained in C57BL/6 than in CBA mice. No increase in IL-4 mRNA was detected. A transient increase in IL-10 mRNA was found in C57BL/6 mice. Separation of spleen cells into CD4+ and CD4- fractions showed that CD4+ T cells produced the bulk of IFN-gamma in both mouse strains and of IL-10 in C57BL/6 mice. Infection of H-2 congenic mice induced a higher level of IFN-gamma mRNA expression by CD4+ T cells in mice with a low rate of clearance (H-2b) than in mice with a high rate of clearance (H-2q). Treatment of infected C57BL/6 mice with anti-IFN-gamma or anti-CD4 monoclonal antibodies indicated that IFN-gamma participates in resistance in the early phase of infection, but not in bacterial clearance, and that CD4+ T cells mediate bacterial clearance during the 3rd week of infection. Taken together, these results suggest that defective bacterial clearance in H-2b mice is not linked to defective IFN-gamma production and that CD4+ T cells mediate bacterial clearance by an IFN-gamma-independent mechanism.     

Mice lacking the type I interleukin-1 receptor do not lose bone mass after ovariectomy

We measured the effects of ovariectomy on the bone mass of mice that lacked type I interleukin-1 receptor (IL-I R1 -/- mice) in two genetic backgrounds (C57BL/6 x 129/Sv and C57BL/6) to investigate the role of interleukin-1 in the actions of estrogen on bone. At three weeks after surgery, ovariectomized wild-type mice decreased trabecular bone volume in the proximal humerus by 70% in a C57BL/6 x 129/Sv background and 48% in a C57BL/6 background compared to sham-operated controls. In contrast, there was no significant decrease in trabecular bone mass in IL-1 R1 -/- mice after ovariectomy. The estrogen status of all groups was confirmed by measurement of uterine wet weight. These results demonstrate that a functional IL-1 response pathway is required for mice to lose trabecular bone mass after ovariectomy in this model and they imply that IL-1 is an important mediator of the effects of ovariectomy on bone mass. Hence, therapeutic interventions that block the effects of IL-1 on bone may be beneficial for treating diseases of rapid bone loss such as post-menopausal osteoporosis.     

Glucose-modified low density lipoprotein enhances human monocyte chemotaxis

In response to stimulation with immobilized anti-CD3 antibody, splenocytes from C57BL/6 and BALB/c mice principally produced INF-gamma and IL-4, respectively. However, both splenocytes equally proliferated in response to ConA. We compared the changes after inoculation with BCG (1 mg/mouse) in their capacity to produce IL-4 or IFN-gamma in response to anti-CD3 antibody and to proliferate in response to ConA. Splenocytes from C57BL/6 and BALB/c mice, that had been inoculated with BCG 4 weeks before, produced IFN-gamma with diminished IL-4 production in response to anti-CD3 antibody. Furthermore these splenocytes became anergic to ConA stimulation and died due to cell apoptosis in stead of proliferation. However, we observed the strain difference at 12 weeks after BCG-infection. BCG-primed C57BL/6 splenocytes, that continuously produced IFN-gamma in response to anti-CD3 antibody, failed to proliferate in response to ConA. In contrast, BCG-primed BALB/c splenocytes, that increased IL-4 production but decreased IFN-gamma production when stimulated with anti-CD3 antibody, could proliferate well in response to ConA. Since the splenocytes of BALB/c mice became ConA responsive along with their shifting from Th1 dominant immune response at 4 weeks to Th2 dominant immune response at 12 weeks after BCG-inoculation, IL-4 was assumed to play a crucial role in activation of anergic T cells. Therefore, we stimulated splenocytes from both strains of mice infected with BCG 4 weeks before with ConA in the presence or absence of IL-4. Splenocytes from BCG-infected BALB/c mice showed marked proliferation, while those from BCG-infected C57BL/6 mice failed. We found that IL-4 protected against ConA-induced cell apoptosis in BALB/c splenocytes but not C57BL/6 splenocytes.     

Dyserythropoiesis and severe anaemia associated with malaria correlate with deficient interleukin-12 production

Complex cytokine interactions occur during blood-stage malaria which offer a unique opportunity to study their influence on the pathogenesis of malarial anaemia. Plasmodium chabaudi AS susceptible A/J mice experience severe and fatal anaemia whereas resistant C57BL/6 (B6) mice survive following moderate anaemia. In this study we analysed the role of IL-12 in erythropoiesis and tested whether the levels of IL-12 produced in these mice correlated with the extent of anaemia. In vitro, IL-12 significantly enhanced the numbers of erythroid burst (BFU-E) and colony forming units (CFU-E) in bone marrow and spleen cells from normal and day 7 infected A/J and B6 mice. Despite the presence of IL-12 in vitro, the level of splenic erythropoiesis in infected A/J mice was significantly lower than in B6 mice. Moreover, sera from infected B6 mice, but not A/J mice, significantly up-regulated erythropoiesis in vitro and this enhancement correlated with several fold higher levels of IL-12 in the sera of B6 compared to A/J mice. Furthermore, the erythropoietic potentiating effect of sera from infected B6 mice was abrogated following depletion of IL-12. Taken together, these findings suggest that defective IL-12 production in A/J mice during the early course of infection may result in fatal anaemia.     

Molecular characterization and functional analysis of murine interleukin 4 receptor allotypes

The murine interleukin 4 receptor (IL-4R) exists as a transmembrane protein transducing pleiotropic IL-4 functions, or as soluble (s)IL-4-binding molecule with potent immunoregulatory effects. In this study we identified and characterized a murine IL-4R allotype. Sequence analysis of the IL-4R cDNA of BALB/c mice revealed 18 base substitutions leading to three extracellular and five cytoplasmic amino acid changes when compared with the published IL-4R sequence of C57BL/6 mice. Analyses with allotype-specific mAbs revealed that AKR/J and SJL/J mice possess the newly identified BALB/c IL-4R allotype whereas the IL-4Rs of C3H, CBA, DBA-2, and FVB/N mice are identical to that of the C57BL/6 mouse. The extracellular Thr49 to Ile substitution abrogates one N-glycosylation site in the naturally occurring BALB/c IL-4R as well as in the experimentally point mutated C57BL/6-T49I sIL-4R, and both molecules display a nearly threefold reduction in IL-4-neutralizing activity compared to the C57BL/6 sIL-4R. In line with this, a significantly enhanced dissociation rate of IL-4 was detected for the BALB/c IL-4R allotype by surface plasmon resonance and in radioligand binding studies with IL-4R-transfected cell lines. These findings suggest that the altered ligand binding behavior of the newly described IL-4R allotype may influence the IL-4 responsiveness, thus contributing to the diverse phenotypes of inbred mouse strains in IL-4-dependent diseases.     

The protein efficiency ratios of 30:70 mixtures of animal:vegetable protein are similar or higher than those of the animal foods alone

C57BL/6 mice receiving pretransplant immunization with C3H.SW spleen cells via the portal vein, but not the vena cava, show Ag-specific delayed rejection of allogeneic C3H.SW skin grafts. This delayed rejection is not seen if preimmunization is performed in gamma delta TCR knockout (C57BL/6-Tcrdtm1Mom) mice. gamma delta TCR+ and alpha beta TCR+ hybridoma cells were prepared from Peyer's patch cells harvested from C57BL/6 mice 4 days following portal venous immunization with 100 x 10(6) irradiated C3H.SW spleen cells and skin grafting with C3H.SW tail skin. After recloning, these hybridoma cells were tested for cytokine production in vitro following restimulation with irradiated C3H.SW spleen cells and for their ability to delay rejection of C3H.SW skin grafts after adoptive transfer to C57BL/6 mice. Delayed graft rejection was a function of cells that showed preferential production of IL-10, not IFN-gamma, in vitro, independent of the source (vena cava or portal vein immunized mice) or the TCR phenotype of the hybridoma. Simultaneous infusion of anti-IL-10 mAb abolished this graft prolongation effect of transferred gamma delta TCR+ hybridomas. Hybridoma cells producing IL-10 on restimulation could polarize cytokine production from freshly stimulated mesenteric lymph node away from production of IL-2 and IFN-gamma, and toward IL-4, IL-10, and TGF-beta production. This immunoregulation by hybridoma cells in vivo and in vitro was observed even for third party Ag-stimulated mice/cells as long as the hybridoma cells themselves received stimulation with their specific Ag.     

Characterization of diadenosine polyphosphate transport into chromaffin granules from adrenal medulla

Allografted tumor rejection does not occur in the absence of T cells, but the main effector cells responsible for the rejection are allograft-induced macrophages (AIM). We examined the roles of T cells in the AIM-mediated rejection of Meth A (H-2d) tumor cells from C57BL/6 (H-2b) mice. Irradiation of C57BL/6 mice abrogated both the induction of AIM and the allograft rejection. Reconstitution of the irradiated mice with F1 (C57BL/6 X C3H/He: H-2b/k) bone marrow cells led to the appearance of H-2b/k haplotype of AIM exclusively in the rejection site and to allograft rejection, indicating that radiosensitive cells prerequisite for both the induction of AIM and allograft rejection were bone marrow-derived cells, and that the progenitors of AIM existed in the bone marrow cells to be activated into AIM in the rejection site. To understand the role of T cells in the induction of AIM, we used adult-thymectomized, X-irradiated C57BL/6 mice reconstituted with F1 bone marrow (ATXBM). The ATXBM mice could neither induce AIM nor reject allogeneic Meth A cells, whereas adoptive transfer of F1 lymph node T cells to the ATXBM mice restored not only the induction of AIM but also rejection of the allograft. Among the lymph node T cells, CD4-, but not CD8+, cells were found to be essential for the activation of AIM progenitors to AIM; and CD8+ T cells were further required for rejection, at least in part, to enhance the number of AIM in the rejection site.     

Characteristics of women choosing birth center care

Certain strains of mice, designated V beta a, have a deletion of the gene segments encoding the beta chain of the T-cell receptor variable region. These mice do not express 40 to 50% of the T-cell receptor V beta chains. In this study, we examined the influence of this deletion on susceptibility to Histoplasma capsulatum. In addition, H. capsulatum-injected V beta a mice were tested for their capacity to generate T-cell dependent responses to H. capsulatum antigens. Susceptibility profiles of V beta a mice, SWR/J (H-2q), SJL/J (H-2s) and C57L-(H-2b), were compared to V beta b strains, C57BL/6 (H-2b) and DBA/l (H-2q), following intravenous (IV) injection of sublethal and lethal inocula of H. capsulatum yeast cells. One week after injection of 6 x 10(5) yeast cells, the spleens of SWR/J, SJL/J and C57L mice contained 5- to 7-fold fewer colony forming units (CFU) than spleens of C57BL/6 mice. Approximately 50% fewer CFU of H. capsulatum were recovered from the spleens of DBA/l mice compared to those from C57BL/6 animals. Subsequently, groups of mice were challenged IV with either 1.5 x 10(7) or 7.5 x 10(6) yeast cells and observed for 30 days. Survival of SWR/J,SJL/J, C57L and DBA/l mice was significantly prolonged compared to C57BL/6 mice. V beta a and DBA/l mice injected with viable H. capsulatum yeast cells mounted a delayed-type hypersensitivity response to an extract from the cell wall and cell membrane of yeast cells and to HIS-62, a purified antigen derived therefrom.(ABSTRACT TRUNCATED AT 250 WORDS)     

Voluntary selection of and tolerance to 1,2 propanediol (propylene glycol) by high and low ethanol-selecting mouse strains.

Tested 15 male mice from each of 4 inbred strains (C57BL/6J, BALB/cJ, CBA/J, and DBA/2J) to determine their voluntary self-selection of a 10% solution of 1,2 propanediol (1,2 PD), a 3-carbon alcohol of low toxicity. As with ethanol, the C57BL/6J strain consumed significantly greater amounts than the 3 other low ethanol-selecting strains. Exp II with 140 Ss determined that the 3 low-selecting strains suffered significantly greater depression of the central nervous system from 1,2 PD than the high selecting C57BL strain. It was also found that ethanol was a much more potent depressant than 1,2 PD. Results are discussed in terms of the possible role of neural sensitivity in regulating consumption levels of the 2 alcohols. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An antagonistic IL-4 mutant prevents type I allergy in the mouse: inhibition of the IL-4/IL-13 receptor system completely abrogates humoral immune response to allergen and development of allergic symptoms in vivo

We have analyzed in vivo effects of the murine IL-4 mutant Q116D/Y119D (QY), which forms unproductive complexes with IL-4Ralpha and is an antagonist for IL-4 and IL-13 in vitro. Treatment of BALB/c mice with QY during immunization with OVA completely inhibited synthesis of OVA-specific IgE and IgG1. BALB/c-derived knockout mice lacking either IL-4 or IL-4Ralpha also did not develop specific IgE or IgG1, but mounted a much stronger IgG2a and IgG2b response than wild-type mice. In contrast, QY treatment of normal BALB/c mice suppressed specific IgG2a, IgG2b, and IgG3 synthesis, which may indicate the development of tolerance toward the allergen. Associated with the lack of IgE synthesis in QY-treated wild-type mice and in IL-4(-/-) mice used as a control was the failure to develop immediate cutaneous hypersensitivity or anaphylactic shock upon rechallenge. Interestingly, QY treatment also inhibited humoral immune responses and allergic reactivity in SJL/J mice, a strain that did not produce IgE, but displayed IgE-independent mast cell degranulation mediated by specific IgG1. We conclude that QY inhibits Ag-specific humoral immune responses and allergic symptoms mediated either by IgE or IgG1. It needs to be clarified how QY abrogates synthesis of IgG2a, IgG2b, and IgG3, but the induction of tolerance toward nonhazardous protein Ags should be advantageous for therapy of atopic disorders and other Th2-dominated diseases.     

Analysis of the role of CD4+ T-cells during murine cytomegalovirus infection in different strains of mice

We examined the role of CD4+ T-cells in peritoneal exudate cells (PECs) during the course of acute murine cytomegalovirus (MCMV) infection in two strains of mice. Cell counts of PECs and cytofluorometric analysis showed that C57BL/6, a resistant strain, had more CD4+ T-cells than BALB/c, a susceptible strain, after intraperitoneal infection of 3 x 10(3) PFU of the Smith strain of MCMV, though both strains had an equivalent number of CD8+ T-cells. CD4+ T-cells of both strains expressed mRNA of IFN-gamma, IL-2, and IL-4 on days 5 and 7 after infection, with much higher expression of these cytokines in C57BL/6 than in BALB/c. At the same time point after infection, macrophages were shown to express mRNA of IL-1 alpha and TNF-alpha with higher expression of IL-1 alpha in C57BL/6 than in BALB/c. Production of nitric oxide, recently shown to be one of the antiviral effector mechanisms of macrophages, by macrophages of both strains was examined showing more production of nitric oxide on day 7 after infection in C57BL/6 than in BALB/c. From these findings, we suggest the possibility that CD4+ T-cells contribute to the protection against MCMV infection via the secretion of cytokines and the resultant activation of macrophages to produce nitric oxide.     

Ambiguous role of interleukin-12 in Yersinia enterocolitica infection in susceptible and resistant mouse strains

Endogenous interleukin-12 (IL-12) mediates protection against Yersinia enterocolitica in C57BL/6 mice by triggering gamma interferon (IFN-gamma) production in NK and CD4+ T cells. Administration of exogenous IL-12 confers protection against yersiniae in Yersinia-susceptible BALB/c mice but exacerbates yersiniosis in resistant C57BL/6 mice. Therefore, we wanted to dissect the different mechanisms exerted by IL-12 during Yersinia infections by using different models of Yersinia-resistant and -susceptible mice, including resistant C57BL/6 mice, susceptible BALB/c mice, intermediate-susceptible wild-type 129/Sv mice, 129/Sv IFN-gamma-receptor-deficient (IFN-gamma R-/-) mice and C57BL/6 tumor necrosis factor (TNF) receptor p55 chain-deficient (TNFR p55-/-) mice. IFN-gamma R-/- mice turned out to be highly susceptible to infection by Y. enterocolitica compared with IFN-gamma R+/+ mice. Administration of IL-12 was protective in IFN-gamma R+/+ mice but not in IFN-gamma R-/- mice, suggesting that IFN-gamma R-induced mechanisms are essential for IL-12-induced resistance against yersiniae. BALB/c mice could be rendered Yersinia resistant by administration of anti-CD4 antibodies or by administration of IL-12. In contrast, C57BL/6 mice could be rendered more resistant by administration of transforming growth factor beta (TGF-beta). Furthermore, IL-12-triggered toxic effects in C57BL/6 mice were abrogated by coadministration of TGF-beta. While administration of IL-12 alone increased TNF-alpha levels, administration of TGF-beta or TGF-beta plus IL-12 decreased both TNF-alpha and IFN-gamma levels in Yersinia-infected C57BL/6 mice. Moreover, IL-12 did not induce toxicity in Yersinia-infected TNFR p55-/- mice, suggesting that TNF-alpha accounts for IL-12-induced toxicity. Taken together, IL-12 may induce different effector mechanisms in BALB/c and C57BL/6 mice resulting either in protection or exacerbation. These results are important for understanding the critical balance of proinflammatory and regulatory cytokines in bacterial infections which is decisive for beneficial effects of cytokine therapy.     

Prospective randomized study of early versus delayed laparoscopic cholecystectomy for acute cholecystitis

We asked whether the likelihood for mice of the C57BL/6J strain to develop glucose intolerance when fed a high-fat diet is related to the increase in circulating levels of leptin or free fatty acids (FFA). We therefore administered a high-fat diet (58% fat) or a control diet (11% fat) for 1.5 years. NMRI mice were used as a more glucose-tolerant control group. After a high-fat diet, the area under the glucose curve following an intraperitoneal glucose challenge (1 g/kg) increased more markedly in C57BL/6J mice (by 42+/-8%) than in NMRI mice (by 21+/-3%, P = 0.007). Plasma levels of insulin, leptin and FFA increased in both strains of mice, whereas plasma glucose levels were elevated after the high-fat diet only in C57BL/6J mice. The slope of the relationship between body weight and plasma leptin was higher in C57BL/6J mice than in NMRI mice. suggesting leptin insensitivity. Circulating leptin correlated to circulating insulin in both strains of mice, whereas plasma FFA correlated to plasma insulin in NMRI mice but not in C57BL/6J mice. These correlations remained significant after adjustment for body weight. The results show that elevated leptin and FFA levels evolve after high-fat feeding in mice, in conjunction with evolvement of glucose intolerance and hyperglycemia.     

Differential effects of the absence of interferon-gamma and IL-4 in acute graft-versus-host disease after allogeneic bone marrow transplantation in mice

Graft-versus-host disease (GVHD), in which immunocompetent donor cells attack the host, remains a major cause of morbidity after allogeneic bone marrow transplantation (BMT). To understand the role of cytokines in the pathobiology of GVHD, we used cytokine knockout (KO) mice as a source of donor T cells. Two different MHC-disparate strain combinations were examined: BALB/c (H2(d)) donors into lethally irradiated C57BL/6 (H2(b)) recipients or C57BL/6 (H2(b)) donors into B10.BR (H2(k)) recipients. Donor cells were from mice in which either the interferon-gamma (IFN-gamma) or the IL-4 gene was selectively disrupted to understand the role of these cytokines in acute GVHD. In both strain combinations the same pattern was noted with regard to GVHD onset and morbidity. All mice exhibited the classic signs of acute GVHD: weight loss with skin, gut, and liver pathology resulting in morbidity and mortality. Surprisingly, donor cells obtained from mice lacking IFN-gamma gave rise to accelerated morbidity from GVHD when compared with cells from wild-type control donors. Similar results were obtained using normal donors when neutralizing antibodies to IFN-gamma were administered immediately after the BMT. These results suggest that IFN-gamma plays a role in protection from acute GVHD. In marked contrast, cells obtained from IL-4 KO mice resulted in protection from GVHD compared with control donors. Splenocytes from IFN KO mice stimulated with a mitogen proliferated to a significantly greater extent and produced more IL-2 compared with splenocytes obtained from IL-4 KO or control mice. Additionally, there was increased IL-2 production in the spleens of mice undergoing GVHD using IFN-gamma KO donors. These results therefore indicate, with regard to the TH1/ TH2 cytokine paradigm, the absence of a TH1-type cytokine can be deleterious in acute GVHD, whereas absence of a TH2 cytokine can be protective.     

IL-5 is required for eosinophil recruitment, crystal deposition, and mononuclear cell recruitment during a pulmonary Cryptococcus neoformans infection in genetically susceptible mice (C57BL/6)

CBA/J (highly resistant), BALB/c (moderately resistant), and C57BL/6 (susceptible) mice displayed three resistance patterns following intratracheal inoculation of Cryptococcus neoformans 52. The inability to clear the infection correlated with the duration of the eosinophil infiltrate in the lungs. The role of IL-5 in promoting the pulmonary eosinophilia and subsequent inflammatory damage in susceptible C57BL/6 mice was investigated. C57BL/6 mice developed a chronic alveolar, peribronchiolar, and perivascular eosinophilia following C. neoformans infection. This resulted in the accumulation of intracellular Charcot-Leyden-like crystals in alveolar macrophages by wk 4 and the extracellular deposition of these crystals in the bronchioles with associated destruction of airway epithelium by wk 6. IL-5 mRNA was expressed in the lungs, and injections of anti-IL-5 mAb prevented eosinophil recruitment and crystal deposition but did not alter cryptococcal clearance. Depletion of CD4+ T cells (but not CD8+) ablated IL-5 production by lung leukocytes in vitro and eosinophil recruitment in vivo. Neutralization of IL-5 also inhibited the recruitment of macrophages, CD8+ T lymphocytes, and B lymphocytes by 47 to 57%. Anti-IL-5 mAb inhibited CD4+ T lymphocyte recruitment by 30% but did not affect neutrophil recruitment. Thus, the development of a chronic eosinophil infiltrate in the lungs of C. neoformans-infected C57BL/6 mice is a nonprotective immune response that causes significant lung pathology. Furthermore, IL-5 promotes the recruitment and activation of eosinophils, resulting in the recruitment of additional macrophages and lymphocytes into the lungs.     

The effects of age and genotype upon the jaw-jerk reflex in inbred mice

The threshold of the jaw-jerk reflex to electrical stimulation of the hard palate was measured in a cross-sectional design using C57BL/6J and DBA/2J mice at 2, 8, 20, 25, and 30 mo of age, in order to assess CNS sensitivity as a function of increasing age. The thresholds of DBA/2J mice were higher than those of C57BL/6J mice at all ages tested. No age-related changes in threshold were observed in mice of either strain.