Involvement of human CD44 during Cryptococcus neoformans infection of brain microvascular endothelial cells

Pathogenic yeast Cryptococcus neoformans causes devastating cryptococcal meningoencephalitis. Our previous studies demonstrated that C. neoformans hyaluronic acid was required for invasion into human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. In this report, we demonstrate that C. neoformans hyaluronic acid interacts with CD44 on HBMEC. Our results suggest that HBMEC CD44 is a primary receptor during C. neoformans infection, based on the following observations. First, anti-CD44 neutralizing antibody treatment was able to significantly reduce C. neoformans association with HBMEC. Second, C. neoformans association was considerably impaired using either CD44-knock-down HBMEC or C. neoformans hyaluronic acid-deficient strains. Third, overexpression of CD44 in HBMEC increased their association activity towards C. neoformans. Fourth, confocal microscopic images showed that CD44 was enriched at and around the C. neoformans association sites. Fifth, upon C. neoformans and HBMEC engagement, a subpopulation of CD44 and actin translocated to the host membrane rafts. Our results highlight the interactions between C. neoformans hyaluronic acid and host CD44 and the dynamic results of these interactions, which may represent events during the adhesion and entry of C. neoformans at HBMEC membrane rafts.     

Invasion of Cryptococcus neoformans into human brain microvascular endothelial cells is mediated through the lipid rafts-endocytic pathway via the dual specificity tyrosine phosphorylation-regulated kinase 3 (DYRK3)

Cryptococcus neoformans is a neurotropic fungal pathogen, which provokes the onset of devastating meningoencephalitis. We used human brain microvascular endothelial cells (HBMEC) as the in vitro model to investigate how C. neoformans traverses across the blood-brain barrier. In this study, we present several lines of evidence indicating that C. neoformans invasion is mediated through the endocytic pathway via lipid rafts. Human CD44 molecules from lipid rafts can directly interact with hyaluronic acid, the C. neoformans ligand. Bikunin, which perturbs CD44 function in the lipid raft, can block C. neoformans adhesion and invasion of HBMEC. The lipid raft marker, ganglioside GM1, co-localizes with CD44 on the plasma membrane, and C. neoformans cells can adhere to the host cell in areas where GM1 is enriched. These findings suggest that C. neoformans entry takes place on the lipid rafts. Upon C. neoformans engagement, GM1 is internalized through vesicular structures to the nuclear membrane. This endocytic redistribution process is abolished by cytochalasin D, nocodazole, or anti-DYRK3 (dual specificity tyrosine-phosphorylation-regulated kinase 3) siRNA. Concomitantly, the knockdown of DYRK3 significantly reduces C. neoformans invasion across the HBMEC monolayer in vitro. Our data demonstrate that the lipid raft-dependent endocytosis process mediates C. neoformans internalization into HBMEC and that the CD44 protein of the hosts, cytoskeleton, and intracellular kinase-DYRK3 are involved in this process.     

SBi4211阻断HIV-1 gp41促进新生隐球菌对人脑微血管内皮细胞的黏附作用

【背景】目前艾滋病和新型隐球菌性脑膜炎共病因素导致其高发病率和死亡率的机制尚不明确。【目的】探索S100B抑制剂SBi4211对HIV-1 gp41促进新生隐球菌黏附人脑微血管内皮细胞的影响和可能机制。【方法】黏附实验分析SBi4211是否能阻断HIV-1 gp41诱导下新生隐球菌黏附人脑微血管内皮细胞。使用免疫印迹方法进一步检测在此过程中SBi4211对脑微血管内皮细胞上新生隐球菌透明质酸受体CD44表达的影响。【结果】SBi4211可显著抑制HIV-1gp41对新生隐球菌黏附脑微血管内皮细胞的增强作用,且呈时间、剂量效应(P0.05);免疫印迹结果显示SBi4211可抑制新生隐球菌和/或HIV-1 gp41增加脑微血管内皮细胞上新生隐球菌透明质酸受体CD44的表达。【结论】SBi4211可通过下调受体CD44来阻断HIV-1 gp41对新生隐球菌黏附人脑微血管内皮细胞的增强效应,这为了解HIV-1与新生隐球菌共病机制及其防治策略提供了新思路。     

Lipid raft/caveolae signaling is required for Cryptococcus neoformans invasion into human brain microvascular endothelial cells

Background

Cryptococcus neoformans has a predilection for central nervous system infection. C. neoformans traversal of the blood brain barrier, composed of human brain microvascular endothelial cells (HBMEC), is the crucial step in brain infection. However, the molecular mechanism of the interaction between Cryptococcus neoformans and HBMEC, relevant to its brain invasion, is still largely unknown.

Methods

In this report, we explored several cellular and molecular events involving the membrane lipid rafts and caveolin-1 (Cav1) of HBMEC during C. neoformans infection. Immunofluorescence microscopy was used to examine the roles of Cav1. The knockdown of Cav1 by the siRNA treatment was performed. Phosphorylation of Cav1 relevant to its invasion functions was investigated.

Results

We found that the host receptor CD44 colocalized with Cav1 on the plasma membrane, and knockdown of Cav1 significantly reduced the fungal ability to invade HBMEC. Although the CD44 molecules were still present, HBMEC membrane organization was distorted by Cav1 knockdown. Concomitantly, knockdown of Cav1 significantly reduced the fungal crossing of the HBMEC monolayer in vitro. Upon C. neoformans engagement, host Cav1 was phosphorylated in a CD44-dependent manner. This phosphorylation was diminished by filipin, a disrupter of lipid raft structure. Furthermore, the phosphorylated Cav1 at the lipid raft migrated inward to the perinuclear localization. Interestingly, the phospho-Cav1 formed a thread-like structure and colocalized with actin filaments but not with the microtubule network.

Conclusion

These data support that C. neoformans internalization into HBMEC is a lipid raft/caveolae-dependent endocytic process where the actin cytoskeleton is involved, and the Cav1 plays an essential role in C. neoformans traversal of the blood-brain barrier.     

Invasion of Cryptococcus neoformans into human brain microvascular endothelial cells requires protein kinase C-alpha activation

Pathogenic fungus Cryptococcus neoformans has a predilection for the central nervous system causing devastating meningoencephalitis. Traversal of C. neoformans across the blood–brain barrier (BBB) is a crucial step in the pathogenesis of C. neoformans . Our previous studies have shown that the CPS1 gene is required for C. neoformans adherence to the surface protein CD44 of human brain microvascular endothelial cells (HBMEC), which constitute the BBB. In this report, we demonstrated that C. neoformans invasion of HBMEC was blocked in the presence of G109203X, a protein kinase C (PKC) inhibitor, and by overexpression of a dominant-negative form of PKCα in HBMEC. During C. neoformans infection, phosphorylation of PKCα was induced and the PKC enzymatic activity was detected in the HBMEC membrane fraction. Our results suggested that the PKCα isoform might play a crucial role during C. neoformans invasion. Immunofluorescence microscopic images showed that induced phospho-PKCα colocalized with β-actin on the membrane of HBMEC. In addition, cytochalasin D (an F-filament-disrupting agent) inhibited fungus invasion into HBMEC in a dose-dependent manner. Furthermore, blockage of PKCα function attenuated actin filament activity during C. neoformans invasion. These results suggest a significant role of PKCα and downstream actin filament activity during the fungal invasion into HBMEC.     

Differential involvement of the hyaluronan (HA) receptors CD44 and receptor for HA-mediated motility in endothelial cell function and angiogenesis.

Hyaluronan (HA), an important glycosaminoglycan constituent of the extracellular matrix, has been implicated in angiogenesis. It appears to exert its biological effects through binding interactions with at least two cell surface receptors: CD44 and receptor for HA-mediated motility (RHAMM). Recent in vitro studies have suggested potential roles for these two molecules in various aspects of endothelial function. However, the relative contribution of each receptor to endothelial functions critical to angiogenesis and their roles in vivo have not been established. We therefore investigated the endothelial expression of these proteins and determined the effects of antibodies against RHAMM and CD44 on endothelial cell (EC) function and in vivo angiogenesis. Both receptors were detected on vascular endothelium in situ, and on the surface of cultured EC. Further studies with active blocking antibodies revealed that anti-CD44 but not anti-RHAMM antibody inhibited EC adhesion to HA and EC proliferation, whereas anti-RHAMM but not CD44 antibody blocked EC migration through the basement membrane substrate, Matrigel. Although antibodies against both receptor inhibited in vitro endothelial tube formation, only the anti-RHAMM antibody blocked basic fibroblast growth factor-induced neovascularization in mice. These data suggest that RHAMM and CD44, through interactions with their ligands, are both important to processes required for the formation of new blood vessels.     

Limited contribution of Toll-like receptor 2 and 4 to the host response to a fungal infectious pathogen, Cryptococcus neoformans

The present study was designed to elucidate the role of Toll-like receptor (TLR) 2 and TLR4 in the host response to Cryptococcus neoformans. Both TLR2 knockout (KO) and TLR4KO mice produced interleukin-1beta (IL-1beta), IL-6, IL-12p40 and tumor necrosis factor-alpha (TNF-alpha) in sera and cleared this fungal pathogen from infected lungs at a comparable level to control littermate (LM) mice. Synthesis of these cytokines was not significantly different in the lungs of these KO mice and LM mice, although IL-1beta, IL-6 and IL-12p40 tended to be lower in TLR2KO, but not TLR4KO, mice than in controls. In addition, there was no significant reduction detected in the synthesis of IL-12 and TNF-alpha by bone marrow-derived dendritic cells from TLR2KO and TLR4KO mice upon stimulation with live yeast cells. Finally, HEK293 cells expressing either TLR2/dectin-1 or TLR4/MD2/CD14 did not respond to C. neoformans in the activation of nuclear factor kappa B (NFkappaB) detected by a luciferase assay. Our results suggest that TLR2 and TLR4 do not or only marginally contribute to the host and cellular response to this pathogen.     

Hyaluronic acid promotes angiogenesis by inducing RHAMM-TGFβ receptor interaction via CD44-PKCδ

Hyaluronic acid (HA) has been shown to promote angiogenesis. However, the mechanism behind this effect remains largely unknown. Therefore, in this study, the mechanism of HA-induced angiogenesis was examined. CD44 and PKCδ were shown to be necessary for induction of the receptor for HA-mediated cell motility (RHAMM), a HA-binding protein. RHAMM was necessary for HA-promoted cellular invasion and endothelial cell tube formation. Cytokine arrays showed that HA induced the expression of plasminogen activator-inhibitor-1 (PAI), a downstream target of TGFβ receptor signaling. The induction of PAI-1 was dependent on CD44 and PKCδ. HA also induced an interaction between RHAMM and TGFβ receptor I, and induction of PAI-1 was dependent on RHAMM and TGFβ receptor I. Histone deacetylase 3 (HDAC3), which is decreased by HA via rac1, reduced induction of plasminogen activator inhibitor-1 (PAI-1) by HA. ERK, which interacts with RHAMM, was necessary for induction of PAI-1 by HA. Snail, a downstream target of TGFβ signaling, was also necessary for induction of PAI-1. The down regulation of PAI-1 prevented HA from enhancing endothelial cell tube formation and from inducing expression of angiogenic factors, such as ICAM-1, VCAM-1 and MMP-2. HDAC3 also exerted reduced expression of MMP-2. In this study, we provide a novel mechanism of HA-promoted angiogenesis, which involved RHAMM-TGFβRI signaling necessary for induction of PAI-1.     

CD44 Plays a Critical Role in Regulating Diet-Induced Adipose Inflammation,Hepatic Steatosis,and Insulin Resistance

CD44 is a multifunctional membrane receptor implicated in the regulation of several biological processes, including inflammation. CD44 expression is elevated in liver and white adipose tissue (WAT) during obesity suggesting a possible regulatory role for CD44 in metabolic syndrome. To study this hypothesis, we examined the effect of the loss of CD44 expression on the development of various features of metabolic syndrome using CD44 null mice. Our study demonstrates that CD44-deficient mice (CD44KO) exhibit a significantly reduced susceptibility to the development of high fat-diet (HFD)-induced hepatic steatosis, WAT-associated inflammation, and insulin resistance. The decreased expression of genes involved in fatty acid synthesis and transport (Fasn and Cd36), de novo triglyceride synthesis (Mogat1), and triglyceride accumulation (Cidea, Cidec) appears in part responsible for the reduced hepatic lipid accumulation in CD44KO(HFD) mice. In addition, the expression of various inflammatory and cell matrix genes, including several chemokines and its receptors, osteopontin, and several matrix metalloproteinases and collagen genes was greatly diminished in CD44KO(HFD) liver consistent with reduced inflammation and fibrogenesis. In contrast, lipid accumulation was significantly increased in CD44KO(HFD) WAT, whereas inflammation as indicated by the reduced infiltration of macrophages and expression of macrophage marker genes, was significantly diminished in WAT of CD44KO(HFD) mice compared to WT(HFD) mice. CD44KO(HFD) mice remained considerably more insulin sensitive and glucose tolerant than WT(HFD) mice and exhibited lower blood insulin levels. Our study indicates that CD44 plays a critical role in regulating several aspects of metabolic syndrome and may provide a new therapeutic target in the management of insulin resistance.     

Tumor necrosis factor-alpha differentially modulates CD44 expression in ovarian cancer cells

Chronic inflammation is implicated in the pathophysiology of ovarian cancer. Tumor necrosis factor-alpha (TNF-alpha), a major inflammatory cytokine, is abundant in the ovarian cancer microenvironment. TNF-alpha modulates the expression of CD44 in normal T lymphocytes and CD44 is implicated in ovarian carcinogenesis and metastases. However, little is known about the role of TNF-alpha in CD44 expression of cancer cells. Recent clinical work using TNF-alpha inhibitors for the treatment of ovarian cancer makes the study of TNF-alpha interactions with CD44 crucial to determining treatment a success or a failure. We studied the effect of TNF-alpha on ovarian cancer cells viability, CD44 expression, and in vitro migration/invasion. Our results revealed that TNF-alpha differentially modulates the expression of CD44 in TNF-alpha-resistant ovarian cancer cells, affecting their in vitro migration, invasion, and binding to hyaluronic acid. TNF-alpha up-regulation of CD44 expression was dependent on the activation of c-Jun NH(2)-terminal kinase (JNK) and this activation was accompanied by an increase in their invasive phenotype. On the contrary, if TNF-alpha failed to induce JNK phosphorylation, the end result was down-regulation of both CD44 expression and the invasive phenotype. These results were confirmed by the use of JNK inhibitors and a TNF receptor competitive inhibitor.     

CD44在隐球菌性脑膜炎发病机制中的作用研究

目的测定隐球菌性脑膜炎小鼠脑组织中CD44表达,探讨CD44在隐球菌性脑膜炎发病机制中的作用。方法隐球菌性脑膜炎免疫抑制小鼠为实验组,未接种隐球菌的免疫抑制小鼠为对照组,应用免疫组化法检测实验组6h、12h、24h、48h、72h、4d、7d小鼠脑组织CD44表达与对照组的变化。结果对照组小鼠脑组织CD44均匀分布在脑细胞膜上。实验组隐球菌作用小鼠48h、72h后,CD44在小鼠脑组织脑膜侧分布增加,而在脑实质侧CD44的分布明显减少。病灶周围的脑组织CD44分布也一侧增加,另一侧分布减少。结论隐球菌侵入小鼠脑组织后,隐球菌诱导CD44向脑组织的一侧移行,向脑膜方向聚集。病灶周围脑组织CD44分布也不均匀。说明隐球菌性脑膜炎的发生与CD44有密切的关系。     

Aggravation of Allergic Airway Inflammation by Cigarette Smoke in Mice Is CD44-Dependent

Background

Although epidemiological studies reveal that cigarette smoke (CS) facilitates the development and exacerbation of allergic asthma, these studies offer limited information on the mechanisms involved. The transmembrane glycoprotein CD44 is involved in cell adhesion and acts as a receptor for hyaluronic acid and osteopontin. We aimed to investigate the role of CD44 in a murine model of CS-facilitated allergic airway inflammation.

Methods

Wild type (WT) and CD44 knock-out (KO) mice were exposed simultaneously to house dust mite (HDM) extract and CS. Inflammatory cells, hyaluronic acid (HA) and osteopontin (OPN) levels were measured in bronchoalveolar lavage fluid (BALF). Proinflammatory mediators, goblet cell metaplasia and peribronchial eosinophilia were assessed in lung tissue. T-helper (Th) 1, Th2 and Th17 cytokine production was evaluated in mediastinal lymph node cultures.

Results

In WT mice, combined HDM/CS exposure increased the number of inflammatory cells and the levels of HA and OPN in BALF and Th2 cytokine production in mediastinal lymph nodes compared to control groups exposed to phosphate buffered saline (PBS)/CS, HDM/Air or PBS/Air. Furthermore, HDM/CS exposure significantly increased goblet cell metaplasia, peribronchial eosinophilia and inflammatory mediators in the lung. CD44 KO mice exposed to HDM/CS had significantly fewer inflammatory cells in BALF, an attenuated Th2 cytokine production, as well as decreased goblet cells and peribronchial eosinophils compared to WT mice. In contrast, the levels of inflammatory mediators were similar or higher than in WT mice.

Conclusion

We demonstrate for the first time that the aggravation of pulmonary inflammation upon combined exposure to allergen and an environmental pollutant is CD44-dependent. Data from this murine model of concomitant exposure to CS and HDM might be of importance for smoking allergic asthmatics.     

TNF regulates thymocyte production by apoptosis and proliferation of the triple negative (CD3-CD4-CD8-) subset

TNF is a proinflammatory cytokine with opposing death/no-death effects in vivo and in vitro. Our studies showed that TNF regulates mouse thymocyte production, inducing both apoptosis and proliferation of the most immature CD3(-)CD4(-)CD8(-) triple negative (TN) subset within a broad range of dosages (10(1)-10(5) pg/ml) in the presence of IL-7. TNF apoptosis affected only the TN3 (CD44(-)CD25(+)) and TN4 (CD44(-)CD25(-)) subsets that expressed both TNFR-p55 and -p75. Although each TNFR alone could mediate TNF apoptosis, maximal apoptosis was seen in C57BL/6J wild type, which expressed both TNFRs. TNF also induced proliferation of TN3 cells at higher doses (10(4)-10(5) pg/ml) mediated only by TNFR-p75. Both anti-TNFR-p55 and -TNFR-p75 mAb inhibited apoptosis but only anti-p75 inhibited proliferation. TNF also regulated TN proliferation to IL-7 because TNFR knockout (KO), TNF KO, and TNF/lymphotoxin alpha and beta triple KO mice showed 2- to 3-fold increased responses not seen in C57BL/6J wild type. In vivo, TNFR KO mice showed thymic hypertrophy with a 60% increase in total thymocytes, with no effect on the CD4/CD8 subsets. We conclude that TNF maintains homeostatic control of total thymocyte production by negative selection of TN3 and TN4 prothymocytes and down-regulation of their proliferation to endogenous IL-7.     

HIV-1 gp41 ectodomain enhances Cryptococcus neoformans binding to human brain microvascular endothelial cells via gp41 core-induced membrane activities

Cryptococcus neoformans causes life-threatening meningoencephalitis, particularly prevalent in AIDS patients. The interrelationship between C. neoformans and HIV-1 is intriguing, as both pathogens elicit severe neuropathological complications. We have previously demonstrated that the HIV-1 gp41 ectodomain fragments gp41-I33 (amino acids 579-611) and gp41-I90 (amino acids 550-639) can enhance C. neoformans binding to HBMECs (human brain microvascular endothelial cells). Both peptides contain the loop region of gp41. In the present study, we used immunofluorescence microscopy and transmission and scanning electron microscopy to explore the underlying mechanisms. Our findings indicated that both C. neoformans and gp41-I90 up-regulated ICAM-1 (intercellular adhesion molecule 1) on the HBMECs and elicited membrane ruffling on the surface of HBMECs. The HIV-1 gp41 ectodomain could also induce CD44 and β-actin redistribution to the membrane lipid rafts, but it could not enhance PKCα (protein kinase Cα) phosphorylation like C. neoformans. Instead, gp41-I90 was able to induce syncytium formation on HBMECs. The results of the present study suggest HIV-1 gp41-enhanced C. neoformans binding to HBMECs via gp41 core domain-induced membrane activities, revealing a potential mechanism of invasion for this pathogenic fungus into the brain tissues of HIV-1-infected patients.     

CD44-deficient mice exhibit enhanced hepatitis after concanavalin A injection: evidence for involvement of CD44 in activation-induced cell death

Administration of Con A induces severe injury to hepatocytes in mice and is considered to be a model for human hepatitis. In the current study, we investigated the role of CD44 in Con A-induced hepatitis. Intravenous administration of Con A (20 mg/kg) caused 100% mortality in C57BL/6 CD44-knockout (KO) mice, although it was not lethal in C57BL/6 CD44 wild-type (WT) mice. Administration of lower doses of Con A (12 mg/kg body weight) into CD44 WT mice induced hepatitis as evident from increased plasma aspartate aminotransferase levels accompanied by active infiltration of mononuclear cells and neutrophils, and significant induction of apoptosis in the liver. Interestingly, CD44 KO mice injected with similar doses of Con A exhibited more severe acute suppurative hepatitis. Transfer of spleen cells from Con A-injected CD44 KO mice into CD44 WT mice induced higher levels of hepatitis when compared with transfer of similar cells from CD44 WT mice into CD44 WT mice. The increased hepatitis seen in CD44 KO mice was accompanied by increased production of cytokines such as TNF-alpha, IL-2 and IFN-gamma, but not Fas or Fas ligand. The increased susceptibility of CD44 KO mice to hepatitis correlated with the observation that T cells from CD44 KO mice were more resistant to activation-induced cell death when compared with the CD44 WT mice. Together, these data demonstrate that activated T cells use CD44 to undergo apoptosis, and dysregulation in this pathway could lead to increased pathogenesis in a number of diseases, including hepatitis.     

Circulating soluble CD4 directly prevents host resistance and delayed-type hypersensitivity response to Cryptococcus neoformans in mice

In the present study, we examined the effect of soluble CD4 (sCD4) on host resistance and delayed-type hypersensitivity (DTH) response to Cryptococcus neoformans using a novel mutant mouse that exhibits a defect in the expression of membrane-bound CD4 but secretes high levels of sCD4 in the serum. In these mice, host resistance to this pathogen was impaired as indicated by an increased number of live pathogens in the lung. To elucidate the mechanism of immunodeficiency, three different sets of experiments were conducted. First, administration of anti-CD4 mAb restored the attenuated host defense. Second, in CD4 gene-disrupted (CD4KO) mice, host resistance was not attenuated compared to control mice. Third, implantation of sCD4 gene-transfected myeloma cells rendered the CD4KO mice susceptible to this infection, while similar treatment with mock-transfected cells did not show such an effect. These results indicated that immunodeficiency in the mutant mice was attributed to the circulating sCD4 rather than to the lack of CD4+ T cells. In addition, DTH response to C. neoformans evaluated by footpad swelling was reduced in the mutant mice compared to that in the control, and the reduced response was restored by the administration of anti-CD4 mAb. Finally, serum levels of IFN-gamma, IL-12 and IL-18 in the mutant mice were significantly reduced, while there was no difference in Th2 cytokines, such as IL-4 and IL-10. Considered collectively, our results demonstrated that sCD4 could directly prevent host resistance and DTH response to C. neoformans through interference with the production of Th1-type cytokines.     

Distinct roles for IL-4 and IL-10 in regulating T2 immunity during allergic bronchopulmonary mycosis

Pulmonary Cryptococcus neoformans infection of C57BL/6 mice is an established model of an allergic bronchopulmonary mycosis that has also been used to test a number of immunomodulatory agents. Our objective was to determine the role of IL-4 and IL-10 in the development/manifestation of the T2 response to C. neoformans in the lungs and lung-associated lymph nodes. In contrast to wild-type (WT) mice, which develop a chronic infection, pulmonary clearance was significantly greater in IL-4 knockout (KO) and IL-10 KO mice but was not due to an up-regulation of a non-T cell effector mechanism. Pulmonary eosinophilia was absent in both IL-4 KO and IL-10 KO mice compared with WT mice. The production of IL-4, IL-5, and IL-13 by lung leukocytes from IL-4 KO and IL-10 KO mice was lower but IFN-gamma levels remained the same. TNF-alpha and IL-12 production by lung leukocytes was up-regulated in IL-10 KO but not IL-4 KO mice. Overall, IL-4 KO mice did not develop the systemic (lung-associated lymph nodes and serum) or local (lungs) T2 responses characteristic of the allergic bronchopulmonary C. neoformans infection. In contrast, the systemic T2 elements of the response remained unaltered in IL-10 KO mice whereas the T2 response in the lungs failed to develop indicating that the action of IL-10 in T cell regulation was distinct from that of IL-4. Thus, although IL-10 has been reported to down-regulate pulmonary T2 responses to isolated fungal Ags, IL-10 can augment pulmonary T2 responses if they occur in the context of fungal infection.