Mice incapable of making IL-4 or IL-10 display normal resistance to infection with Mycobacterium tuberculosis

With a view to determining whether production of Th2 cytokines, IL-4 or IL-10, is responsible for the inability of mice to resolve infection with Mycobacterium tuberculosis, mice with targeted disruption of their IL-4 or IL-10 gene were compared with wild-type mice in terms of their ability to defend against an M. tuberculosis infection initiated via the respiratory route. The results show that mice that are unable to make either IL-4 or IL-10 are no more capable than wild-type mice at defending against tuberculosis (TB). Therefore, the results are inconsistent with the proposition that the inadequacy of Th1-mediated anti-tuberculosis immunity is due to its down-regulation by either of these Th2 cytokines.     

Both interleukin-4 (IL-4) and IL-4 receptor alpha signaling contribute to the development of hepatic granulomas with optimal antileishmanial activity

The roles of interleukin-4 (IL-4) and IL-13 in the regulation of immunity to Leishmania donovani infection are still poorly understood. Here we show that the increased parasite load observed in IL-4(-/-) and IL-4 receptor alpha(-/-) mice correlates with retarded granuloma maturation and antileishmanial activity and that the increased parasite load observed in IL-4 receptor alpha(-/-) mice correlates with increased NOS2 expression and decreased serum gamma interferon levels. IL-4 and IL-13 appear to play little role in regulating collagen deposition in L. donovani-induced granulomas.     

Cytokine and chemokine responses in a cerebral malaria-susceptible or -resistant strain of mice to Plasmodium berghei ANKA infection: early chemokine expression in the brain

A comparative study was carried out on cytokine and chemokine responses in a cerebral malaria (CM)-susceptible or -resistant strain of mice (C57BL/6 or BALB/c respectively) in Plasmodium berghei ANKA infection. C57BL/6 mice died by 10 days after infection when parasitemia was approximately 15-20% with cerebral symptoms, while BALB/c mice survived until week 3 after infection. Although both strains showed T(h)1-skewed responses on day 4 after infection, significantly higher levels of IFN-gamma, tumor necrosis factor (TNF)-alpha and NO were observed during the course of the infection in BALB/c, suggesting that T(h)1 responses are involved in the resistance. Interestingly, in the brain, both strains expressed IFN-inducible protein of 10 kDa (IP-10) and monocyte chemotactic protein (MCP)-1 genes as early as at 24 h post-infection, whereas some differences were observed between both strains thereafter, i.e. enhanced expression of RANTES in C57BL/6, and of IFN-gamma and TNF-alpha in BALB/c respectively. Moreover, the expression of IP-10 and MCP-1 genes in KT-5, an astrocyte cell line, was induced in vitro upon stimulation with a crude antigen of malaria parasites. These results suggest that the direct involvement of brain parenchymal cells takes place in response to plasmodial infection, providing a new aspect to analyze possible mechanisms of CM. This is the first report on the chemokine expression in neuroglial cells in response to malaria infection.     

Inverse regulation of interleukin-6 (IL-6) and IL-6 receptor in histamine deficient histidine decarboxylase-knock-out mice

Interleukin-6, a multifunctional cytokine upon binding to its receptor on hepatocytes regulates production of acute phase proteins involved in local and systemic inflammation. Gene expression and biosynthesis of IL-6 and its receptor (IL-6 R/gp130) is under complex regulation. Histamine, in addition to its principal role in immediate type hypersensitivity has been described to modulate IL-6 production and expression of IL-6 receptor. In this study, the IL-6 and IL-6 receptor expression was examined in histamine deficient histidine decarboxylase (HDC) knock-out mouse model. Our data suggest that in histamine deficient mice the inducibility of IL-6 is significantly reduced, whilst more IL-6 receptor/gp130 mRNA expresses in the liver than in wild type (HDC^+/+) mice. These in vivo findings confirm earlier in vitro results and emphasize the efficacy of antihistamines in local IL-6 related processes.     

Responses to Leishmania donovani in mice deficient in interleukin-12 (IL-12), IL-12/IL-23, or IL-18

Interleukin-12 (IL-12) orchestrates acquired resistance in intracellular Leishmania donovani infection in the liver, inducing gamma interferon and, in turn, macrophage activation and parasite killing. Nevertheless, testing in IL-18(-/-) mice compared to wild-type mice and in IL-12p40(-/-) compared to IL-12p35(-/-) mice also suggested both early-acting (IL-18) and late-acting (IL-23) antileishmanial effects independent of IL-12.     

Male and female 5-HT(1B) receptor knockout mice have higher body weights than wildtypes.

5-HT(1B) receptors have a regulatory role in serotonergic activity and influence feeding behavior and body weight. Because the absence of 5-HT(1B) receptors may cause changes in this regulation, body weight was measured in male and female 5-HT(1B) receptor knockout (5-HT(1B) KO) and wildtype (WT) mice from weaning until the age of 30 weeks. In both genders, 5-HT(1B) KO mice had a higher body weight than WT mice (17% and 9%, respectively). Body weight was significantly higher for males over the entire period and for females from Week 18 onwards. Absolute food and water consumption were related to body weight. However, relative to body weight, males consumed more than females. 5-HT(1B) KO males drank strikingly more water. Housing mice singly reduced food and water intake in males, but not in females. Plasma leptin levels and most organ weights did not differ between genotypes, indicating that higher body weight in 5-HT(1B) KO mice is not related to obesity. Relative to body weight, brains and adrenals were larger in females, while heart and liver were smaller. Kidneys were smaller in females, but larger in 5-HT(1B) KO mice, while lungs showed opposite effects. Spleen and testes were smaller in 5-HT(1B) KO mice. Although 5-HT(1B) KO males are more aggressive, testosterone levels were not different from WT mice. Basal corticosterone levels were similar in all groups and increased in response to mild stress, particularly in females. Lifelong absence of 5-HT(1B) receptors in mice resulted in clear phenotypic differences in body weights and food and water intake. Lacking this receptor increases body growth, without signs of obesity. A potential genetic background effect influencing this phenotype is discussed.     

Mice genetically deficient in immunoglobulin E are more permissive hosts than wild-type mice to a primary,but not secondary,infection with the filarial nematode Brugia malayi

Primary and secondary murine and human infections with Brugia malayi are characterized by substantial increases in levels of immunoglobulin E (IgE). To investigate whether this is necessary for worm clearance, IgE(-/-) mice were subjected to primary- and secondary-infection protocols. Following a primary infection, IgE(-/-) mice displayed a profound deficit in their ability to clear an intraperitoneal injection of L3 infective-stage larvae in comparison to wild-type counterparts and maintained substantial worm burdens as late as 10 weeks postinfection. Although viable adult parasites were recovered at this late time point from IgE(-/-) mice, the majority of the mice remained free of microfilariae. IgE(-/-) cohorts subjected to a secondary-infection protocol were able to clear the challenge inoculation in an accelerated manner, with kinetics similar to that observed in the wild-type animals. Analysis of the humoral response in IgE(-/-) mice following infection demonstrates a defect in IgG1 and IgG2a production, in addition to the expected lack of IgE. The IgG1 deficiency is no longer evident following a secondary infection. These data imply that deficiencies other than IgE production (i.e., IgG1 production) deficiency may be responsible for the increased permissiveness of IgE(-/-) mice as hosts following infection with B. malayi.     

Induction of interleukin-4 (IL-4) by legionella pneumophila infection in BALB/c mice and regulation of tumor necrosis factor alpha, IL-6, and IL-1beta

Infection of BALB/c mice with a sublethal concentration of Legionella pneumophila causes an acute disease that is resolved by innate immune responses. The infection also initiates the development of adaptive Th1 responses that protect the mice from challenge infections. To study the early responses, cytokines induced during the first 24 h after infection were examined. In the serum, interleukin-12 (IL-12) was detectable by 3 h and peaked at 10 h, while gamma interferon was discernible by 5 h and peaked at 8 h. Similar patterns were observed in ex vivo cultures of splenocytes. A transient IL-4 response was also detected by 3 h postinfection in ex vivo cultures. BALB/c IL-4-deficient mice were more susceptible to L. pneumophila infection than were wild-type mice. The infection induced higher serum levels of acute-phase cytokines (tumor necrosis factor alpha [TNF-alpha], IL-1beta, and IL-6), and reducing TNF-alpha levels with antibodies protected the mice from death. Moreover, the addition of IL-4 to L. pneumophila-infected macrophage cultures suppressed the production of these cytokines. Thus, the lack of IL-4 in the deficient mice resulted in unchecked TNF-alpha production, which appeared to cause the mortality. Monocyte chemoattractant protein-1 (MCP-1), a chemokine that is induced by IL-4 during Listeria monocytogenes infection, was detected at between 2 and 30 h after infection. However, MCP-1 did not appear to be induced by IL-4 or to be required for the TNF-alpha regulation by IL-4. The data suggest that the early increase in IL-4 serves to regulate the mobilization of acute phase cytokines and thus controls the potential harmful effects of these cytokines.     

Mice lacking interleukin-2 (IL-2)/IL-15 receptor beta chain are susceptible to infection with avirulent Salmonella enterica subsp. enterica serovar choleraesuis but mice lacking IL-2 are resistant

Interleukin-2 (IL-2)/IL-15 receptor beta (IL-15R beta)(-/-) mice were susceptible to infection with avirulent Salmonella enterica subsp. enterica serovar Choleraesuis, whereas IL-2(-/-) mice were resistant. A natural killer cell response was not evident for both types of deficient mice. A Th1 response was detected in IL-2(-/-) but not in IL-2/IL-15R beta(-/-) mice infected with Salmonella, suggesting that IL-2/IL-15R beta signaling is important for the generation of protective Th1 cells.     

Role of Toll interleukin-1 receptor (IL-1R) 8, a negative regulator of IL-1R/Toll-like receptor signaling, in resistance to acute Pseudomonas aeruginosa lung infection

Toll interleukin-1 receptor (IL-1R) 8 (TIR8), also known as single Ig IL-1 receptor (IL-R)-related molecule, or SIGIRR, is a member of the IL-1R-like family, primarily expressed by epithelial cells. Current evidence suggests that TIR8 plays a nonredundant role as a negative regulator in vivo under different inflammatory conditions that are dependent on IL-R and Toll-like receptor (TLR) activation. In the present study, we examined the role of TIR8 in innate resistance to acute lung infections caused by Pseudomonas aeruginosa, a Gram-negative pathogen responsible for life-threatening infections in immunocompromised individuals and cystic fibrosis patients. We show that Tir8 deficiency in mice was associated with increased susceptibility to acute P. aeruginosa infection, in terms of mortality and bacterial load, and to exacerbated local and systemic production of proinflammatory cytokines (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], IL-1β, and IL-6) and chemokines (CXCL1, CXCL2, and CCL2). It has been reported that host defense against P. aeruginosa acute lung infection can be improved by blocking IL-1 since exaggerated IL-1β production may be harmful for the host in this infection. In agreement with these data, IL-1RI deficiency rescues the phenotype observed in Tir8-deficient mice: in Tir8-/- IL-1RI-/- double knockout mice we observed higher survival rates, enhanced bacterial clearance, and reduced levels of local and systemic cytokine and chemokine levels than in Tir8-deficient mice. These results suggest that TIR8 has a nonredundant effect in modulating the inflammation caused by P. aeruginosa, in particular, by negatively regulating IL-1RI signaling, which plays a major role in the pathogenesis of this infectious disease.     

Immunoregulation by recombinant interleukin-4 receptor (IL-4-R) of murine GvH and SLE-like diseases in BDF1 hybrid mice and MRL/lpr autoimmune mice

Due to the immunopharmacological profile of soluble recombinant interleukin-4 receptor (IL-4-R) to bind specifically the corresponding ligand Il-4 and there-by to modulate biological activity upon exogenous administration in various autoimmune disease models, we further elucidated the disease modifying potential of IL-4-R on the development of a systemic lupus erythematosus (SLE)-like disease in MRL/lpr autoimmune mice and on a chronic graft vs. host (GvH) reaction in BDF1 hybrid mice. Treating autoimmune MRL/lpr mice, which spontaneously develop a SLE-like disease with murine IL-4-R, resulted in a decrease in the amount of autoantibodies and inhibited proteinuria of the developing glomerulonephritis. Also, an improved survival rate was observed, and at the same time the percentage of animals with swollen lymph nodes was lowered and splenomegaly was inhibited. Even in the established disease of MRL/lpr mice, the cytokine receptor reduced the levels of autoantibodies and the kidney malfunctions. When sensitized BDF1 mice were treated intravenously with murine IL-4-R during the induction phase of the disease, the development of a glomerulonephritis (proteinuria) was inhibited, the increase in total IgE was strongly reduced and the survival rate was improved in this model. Even a therapeutic effect in reducing chronic GvH related symptoms was demonstrated when recombinant IL-4-R was given during the disease after the appearance of clinical signs in the hybrid mice.     

Oral immunization of interleukin-4 (IL-4) knockout mice with a recombinant Salmonella strain or cholera toxin reveals that CD4+ Th2 cells producing IL-6 and IL-10 are associated with mucosal immunoglobulin A responses.

Mucosal immunoglobulin A (IgA) responses are often associated with Th2-type cells and derived cytokines, and interleukin-4 (IL-4) knockout (IL-4-/-) mice with impaired Th2 cells respond poorly to oral antigens. However, we have noted that IL-4-/- mice have normal mucosal IgA levels, which led us to query whether different oral delivery systems could elicit mucosal immunity. Two oral regimens were used: (i) a live recombinant Salmonella strain which expresses fragment C (ToxC) of tetanus toxin, and (ii) soluble tetanus toxoid (TT) with cholera toxin (CT) as an adjuvant. Oral immunization of IL-4-/- mice with recombinant Salmonella vaccine expressing ToxC induced brisk mucosal IgA and serum IgG (mainly IgG2a) anti-TT antibody responses. TT-specific CD4+ T cells from spleen or Peyer's patches produced gamma interferon, indicative of Th1 responses; however, IL-6 and IL-10 were also seen. Oral immunization of IL-4-/- mice with TT and CT induced weak mucosal IgA to TT; however, brisk IgA anti-CT-B responses and CT-B-specific CD4+ T cells producing IL-6 and IL-10 were also noted. These results show that although IL-4-dependent antibody responses are impaired, mucosal IgA responses are induced in IL-4-/- mice. These result suggest that certain cytokines, i.e., IL-6 and IL-10 from Th2-type cells, play an important compensatory role in the induction and regulation of mucosal IgA responses.     

Rescue of human T cells by interleukin-9 (IL-9) from IL-2 deprivation-induced apoptosis: correlation with alpha subunit expression of the IL-9 receptor.

Interleukin-9 (IL-9) is a Th2-derived cytokine that uses the gamma-chain of the IL-2 receptor for signaling. Therefore, the responsiveness of human Th1 and Th2 cell clones to IL-9 was measured by examining the ability of this cytokine to prevent apoptosis induced by IL-2 deprivation. A time course study demonstrated that both subsets of T cell clones underwent apoptosis with similar kinetics when deprived of IL-2 and that viability could be maintained by the addition of either IL-4 or IL-7. Interestingly, IL-9 prevented apoptosis in only 2 (Th2) of 14 clones tested. Analysis of IL-9R alpha subunit expression on 18 T cell clones revealed that IL-9 responsiveness was directly proportional to the expression of the high-affinity receptor. IL-9 responsiveness was also dependent on long-term culturing because neither freshly isolated nor 3-day phytohemagglutinin (PHA)-stimulated peripheral blood lymphocytes (PBL) expressed IL-9R alpha. In summary, the data showed that IL-9 can rescue only a small subset of Th2 cells from apoptosis induced by growth factor withdrawal and that expression of IL-9R alpha is required for the antiapoptotic signals mediated by this cytokine.     

The capacity to produce IFN-gamma rather than the presence of interleukin-4 determines the resistance and the degree of susceptibility to Leishmania donovani infection in mice.

The immune response against Leishmania donovani infection has been investigated in one resistant mouse strain (C3H/HeJ) and three susceptible mouse strains (C57BL/6, BALB/c, and B10D2/n). In order to correlate the strain-specific course of infection with the individual T cell response phenotype, the ex vivo cytokine secretion patterns of splenic lymphocytes were assessed by ELISA (interferon-y [IFN-gamma], interleukin-4 [IL-4], IL-10) or by bioassay (IL-2). The strain-dependent differences in the course of infection correlated closely with the potency of T cells to produce IFN-gamma. C3H/HeJ mice produced high amounts of IFN-gamma before and during infection, whereas susceptible mice produced low amounts of IFN-gamma early during L. donovani infection. However, C57BL/6 mice, which recovered from the infection rapidly after the acute stage, developed marked IFN-gamma response within the first 30 days of infection. In contrast, in BALB/c and B10D2/n mice, the IFN-gamma production diminished during the acute stage, and this was associated with a delay in recovery and with subsequent switching into the chronic stage. Interestingly, CD8+ T cells contributed significantly to IFN-gamma production during this phase. In contrast to IFN-y, the levels of IL-4 in response to antigen or mitogen ex vivo were always very low. Moreover, neutralization of endogenous IL-4 in vivo by treatment with soluble murine IL-4 receptor did not result in significant decreases in the parasite burdens in spleen and liver but did cause a decrease in the serum IgE level of L. donovani-infected BALB/c mice. These results confirm that in visceral leishmaniasis a Thl-dominated immune response is protective against the L. donovani parasites and, furthermore, that the capacity to produce IFN-gamma rather than the presence of IL-4 determines the efficacy of the immune response in susceptible mice. The data show that CD8+ T cells represent an important source of IFN-gamma during L. donovani infection in susceptible mice, implying a role for this cell type in healing and development of protective immunity.     

Toll-like receptor 4 (TLR4) does not confer a resistance advantage on mice against low-dose aerosol infection with virulent type A Francisella tularensis

Francisella tularensis, the causative agent of tularemia, is a gram-negative facultative intracellular bacterium. Toll-like receptor (TLR) 4 is considered to be critical for inducing host innate immunity against many gram-negative bacteria including many respiratory pathogens. To determine the role of TLR4 in host defense against airborne F. tularensis infection, TLR4-defective C3H/HeJ (TLR4(d)) or wild-type C3H/HeOuJ (WT) mice were challenged by low-dose aerosol with type A F. tularensis, and the course of the infection and host responses were compared at day 2 and 4 post-inoculation (dpi). At dpi 2, bacterial burdens in the lungs were similar between TLR4(d) and WT mice, but TLR4(d) mice surprisingly harbored approximately 10-fold fewer bacteria in their spleens and livers. However, the bacterial burdens at dpi 4, the mortality and median time to irreversible moribundity were indistinguishable between the two mouse strains. In addition, the inflammatory responses to the infection, as reflected by the cytokine levels and leukocyte influx in the bronchoalveolar lavage fluid and histopathological analysis, were similar between both mouse strains. Additionally, as with C3H mice, we found no difference in either the median time to death or the survival rate between TLR4-deleted C57BL/10ScNJ mice and WT C57BL/10 mice. Combined, these data suggest that TLR4 does not contribute to resistance of mice to airborne type A F. tularensis infection.     

Infection with Mycobacterium avium induces production of interleukin-10 (IL-10), and administration of anti-IL-10 antibody is associated with enhanced resistance to infection in mice.

Organisms of the Mycobacterium avium complex are associated with disseminated infection in patients with AIDS. The mechanisms that account for the survival of the intracellular bacteria are unknown. We document here that infection of C57BL/6 black mice with M. avium 101 triggered interleukin-10 (IL-10) production. The synthesis of IL-10 peaked after 2 weeks of infection and remained elevated throughout the period of infection. Treatment of M. avium-infected peritoneal macrophages with recombinant IL-10 suppressed the stimulatory effect of tumor necrosis factor alpha and granulocyte-macrophage colony-stimulating factor. To confirm the possible role of IL-10 in the infection in vivo, mice were infected with M. avium 101 and simultaneously received treatment with neutralizing anti-IL-10 antibody. After 4 weeks the animals were harvested and the numbers of viable bacteria were quantitated in the liver, spleen, and blood. The liver and spleen of animals receiving anti-IL-10 antibody had 2 to 3 log units fewer bacteria than did those of control animals. These results suggest a role for IL-10 in the pathogenesis of M. avium infection.     

Enhanced resistance of mice to infection with Langat (TP21) virus following pre-treatment with Sindbis or Semliki forest virus.

Significant protection to heterologous i.c. challenge with the flavovirus Langat occurred after a single i.c. injection of avirulent strains of the alpha viruses Semliki Forest or Sindbis given 1 day to 5 weeks before challenge. Some protection also occurred after an i.p. infection with these viruses. We consider that the protection afforded by the alpha viruses is due to interference with the multiplication of Langat virus and is related to the maximum level of brain infectivity reached in the alpha virus infection.     

IL-10RA基因多态性及其与系统性红斑狼疮关系的研究

目的:确定SLE模型小鼠IL-10RA基因变异及其与SLE表现型是否存在关联。方法:用微卫星遗传标记及数量性状位点(QTL)分析方法确定SLE模型小鼠B/W F1的SLE易感基因精确染色体定位并选取候选易感基因,对候选易感基因进行测序分析,选取有基因序列异常的候选易感基因进行PCR-SSCP分析,确定候选易感基因碱基序列变异位点与抗染色质抗体、抗DNA抗体,抗组蛋白抗体及蛋白尿等SLE表现型的相关关系。结果:QTL分析结果表明B/W F1×NZB小鼠抗染色质抗体易感基因与NZW型IL-10RA基因紧密连锁;测序分析发现IL-10RA基因编码区有18处碱基变异,其中7处碱基变异将导致编码氨基酸的变异;抗染色质抗体、抗DNA抗体,抗组蛋白抗体及蛋白尿等SLE表现型与NZW型IL-10RA基因密切相关。另一种SLE模型小鼠MRL的IL-10RA基因存在相同变异。结论:NZW小鼠IL-10RA基因编码区碱基序列存在变异,B/W F1×NZB小鼠SLE表现型与NZW小鼠第9染色体IL-10RA编码区碱基变异相关,提示IL-10RA可能是SLE模型小鼠的一个SLE易感基因。