Biomedical subjects

K I Matthaei

Publications and source records attributed to K I Matthaei.

At least 37 records · Page 2Linked to original sources

PubMed2000

Interleukin-5 deficient mice exhibit impaired host defence against challenge Trichinella spiralis infections.

Enteric nematode infections are characterized by both peripheral and tissue eosinophilia. The cytokine interleukin (IL)-5 is considered a critical factor in the proliferation and recruitment of eosinophils, however, studies suggest it plays little role in host defence, at least during primary Trichinella spiralis infections. Less is known concerning its role in host defence or in the inflammatory response that develops against challenge infections with the same parasite. We examined these questions by infecting IL-5 deficient and wild-type mice, with T. spiralis parasites. Both strains expelled the primary infection by day 21. Forty days after the primary infection, we challenged the mice with a second T. spiralis infection and counted tissue eosinophils and worms in the intestine. While wild-type mice developed a large tissue eosinophilia, IL-5 deficient mice showed little increase in eosinophil numbers within the intestine. Throughout the challenge infection, significantly larger worm burdens were recovered from IL-5 deficient mice, and worm expulsion was also significantly slower (day 21) compared to wild-type mice (day 14). Thus, unlike in a primary infection, IL-5 is not only essential for the onset of intestinal eosinophilia, but also makes a significant contribution to enteric host defence during challenge T. spiralis infections.

Animals↗

PubMed2000

The flightless I protein localizes to actin-based structures during embryonic development.

The product of the flightless I gene is predicted to provide a link between molecules of an as yet unidentified signal transduction pathway and the actin cytoskeleton. Previous work has shown that weak and severe mutations of the flightless I locus in Drosophila melanogaster cause disruption in the indirect flight muscles and in embryonic cellularization events, respectively, indicative of a regulatory role for the flightless I protein in cytoskeletal rearrangements. A C-terminal domain within flightless I with significant homology to the gelsolin-like family of actin-binding proteins has been identified, but evidence of a direct interaction between endogenous flightless I and actin remains to be shown. In the present study, chick, mouse and Drosophila melanogaster embryos have been examined and the localization of flightless I investigated in relation to the actin cytoskeleton. It is shown that flightless I localization is coincident with actin-rich regions in parasympathetic neurons harvested from chicks, in mouse blastocysts and in structures associated with cellularization in Drosophila melanogaster.

3T3 Cells↗

PubMed2000

Uterine eosinophils and reproductive performance in interleukin 5-deficient mice.

Interleukin 5 is expressed in type 2 T lymphocytes and has a key role in driving the differentiation, recruitment and activation of eosinophils. Mice with a null mutation in the interleukin 5 gene (IL-5 -/- mice) have altered type 2 immune responses and severely depleted eosinophil populations. In the present study, the effect of interleukin 5 deficiency on the abundant population of eosinophils present in the female reproductive tract was investigated, and the reproductive performance in C57Bl/6 IL-5 -/- mice was measured. Endometrial eosinophils, detected on the basis of their endogenous peroxidase activity, were reduced in number by four-sevenfold during the oestrous cycle and in early pregnancy in IL-5 -/- mice. Eosinophils present in the cervix and decidual tissues at the time of parturition were similarly diminished. The temporal fluctuations in eosinophil recruitment and localization within these tissues were otherwise unchanged, indicating that interleukin 5 is not a necessary chemotactic agent in the female reproductive tract. Oestrous cycles were moderately greater in duration in IL-5 -/- mice (mean +/- SD = 5.6 +/- 1.0 days in IL-5 -/- mice versus 5.0 +/- 0.8 days in IL-5 +/+ mice), owing to an extended period in oestrus (2.7 +/- 0.9 days per cycle in IL-5 -/- mice versus 1.8 +/- 0.7 in IL-5 +/+ mice). The interval between placing females with males and the finding of copulatory plugs was reduced significantly in interleukin 5-deficient mice. Implantation rates and subsequent fetal development were comparable in IL-5 -/- and IL-5 +/+ mice, irrespective of whether pregnancies were sired by syngeneic (C57Bl/6) or allogeneic (CBA or Balb/c) males, apart from a 10% increase in placental size and a 6.5% decrease in placental&ratio;fetal ratio seen on day 17 in pregnancies sired by CBA males. Parturition and post-partum uterine repair were not compromised in interleukin 5-deficient mice, as judged by the length of gestation, and the outcomes of pregnancies initiated at post-partum oestrus. The birth weights and growth trajectories of pups were significantly influenced by interleukin 5 status, with small but significant increases in the weights of IL-5 -/- pups, particularly C57Bl/6 and CBA F(1) animals, remaining evident until adulthood. These data are consistent with the view that eosinophils have a role in endometrial tissue remodelling associated with the oestrous cycle, but indicate that the events of pregnancy and parturition proceed quite normally in the absence of maternal and fetal interleukin 5. However, strain-dependent effects of interleukin 5 deficiency on placental growth and function and subsequent weight gain in the newborn indicate that this cytokine may act through the maternal or fetal immune axis to exert subtle influences on reproductive outcome.

Analysis of Variance↗

PubMed1999

Stress induces neurogenesis in non-neuronal cell cultures of adult olfactory epithelium.

Among the basal cells of the olfactory epithelium is a stem cell which divides and whose progeny differentiate into new sensory neurons throughout adult life. Olfactory neurogenesis is highly regulated, for example it is stimulated by epithelial damage. Previous reports implicate several growth factors in progenitor cell proliferation and neuronal differentiation in vitro but these studies differ in growth conditions and age of donors making it difficult to determine precisely the roles of neurogenic stimuli and their sites of action. The aims of the present study were to develop purified basal cell cultures from adult olfactory epithelium and to stimulate neurogenesis in defined growth conditions in order to elucidate the cellular mechanisms by which neurogenesis is stimulated after epithelial damage. We show here that differentiated olfactory sensory neurons arise after biochemical or mechanical stress of rat and mouse olfactory epithelial cell cultures in the absence of growth factors, complex media (e.g., serum, conditioned media, pituitary and hypothalamic extracts), or other cells (e.g., explants, feeder layers of glia, or other non-epithelial cells). Prior to the stress, these cultures contained basal cells and supporting cells but not neurons. After the stress, some cells differentiated into bipolar neurons expressing a number of neuronal proteins including olfactory marker protein. Bromodeoxyuridine experiments show that the differentiated neurons arose from recently divided cells which did not divide again before differentiating. We conclude that stress disrupts cell surface contacts to induce the immediate neuronal precursors to undergo final differentiation into olfactory sensory neurons. This may be a mechanism for enhanced neurogenesis after epithelial damage.

Age Factors↗

PubMed1999

IL-5 contributes to worm expulsion and muscle hypercontractility in a primary T. spiralis infection.

Enteric nematode infections lead to increased interleukin (IL)-5 expression, eosinophilic inflammation, and intestinal smooth muscle hypercontractility. Although eosinophils release inflammatory mediators that cause smooth muscle contraction, the role of IL-5 and eosinophils in enteric smooth muscle hypercontractility is unclear. IL-5-deficient mice and their wild-type controls were infected with the nematode Trichinella spiralis. Intestinal parasites and eosinophils were counted, and jejunal longitudinal muscle contractility was assessed. During infection, IL-5 gene expression increased significantly in wild-type mice and was accompanied by significant intestinal eosinophilia in wild-type but not IL-5-deficient mice. Although both strains developed increased muscle contractility during infection, contraction was significantly less in the IL-5-deficient mice at days 16 and 21 postinfection. In addition, parasite expulsion was transiently delayed at day 16 in IL-5-deficient mice. Thus, in the nematode-infected mouse, IL-5 appears essential for intestinal eosinophilia and contributes to, but is not essential for, the development of muscle hypercontractility. IL-5 also appears to play a minor role in expelling a primary T. spiralis infection from the gut.

Animals↗

PubMed1998

Circulating, but not local lung, IL-5 is required for the development of antigen-induced airways eosinophilia.

IL-5 is induced locally in the lung and systemically in the circulation during allergic airways eosinophilic inflammation both in humans and experimental animals. However, the precise role of local and systemic IL-5 in the development of allergic airways eosinophilia remains to be elucidated. In our current study, we demonstrate that compared with their IL-5(+/+) counterparts, IL-5(-/-) mice lacked an IL-5 response both in the lung and peripheral blood, yet they released similar amounts of IL-4, eotaxin, and MIP-1alpha in the lung after ovalbumin (OVA) sensitization and challenge. At cellular levels, these mice failed to develop peripheral blood and airways eosinophilia while the responses of lymphocytes, neutrophils, and macrophages remained similar to those in IL-5(+/+) mice. To dissect the relative role of local and systemic IL-5 in this model, we constructed a gene transfer vector expressing murine IL-5. Intramuscular IL-5 gene transfer to OVA-sensitized IL-5(-/-) mice led to raised levels of IL-5 compartmentalized to the circulation and completely reconstituted airways eosinophilia upon OVA challenge, which was associated with reconstitution of eosinophilia in the bone marrow and peripheral blood. Significant airways eosinophilia was observed for at least 7 d in these mice. In contrast, intranasal IL-5 gene transfer, when rendered to give rise to a significant but compartmentalized level of transgene protein IL-5 in the lung, was unable to reconstitute airways eosinophilia in OVA-sensitized IL-5(-/-) mice upon OVA-challenge, which was associated with a lack of eosinophilic responses in bone marrow and peripheral blood. Our findings thus provide unequivocal evidence that circulating but not local lung IL-5 is critically required for the development of allergic airways eosinophilia. These findings also provide the rationale for developing strategies to target circulating IL-5 and/or its receptors in bone marrow to effectively control asthmatic airways eosinophilia.

Adenoviridae↗

PubMed1998

Overexpression of fra-2 in transgenic mice perturbs normal eye development.

The major components of transcription factor AP-1 (Activator Protein 1) are encoded by the two families of genes related to the proto-oncogenes c-fos and c-jun. The fos-related antigen-2 (fra-2) gene is the most recently described member of the Fos family. To determine the oncogenic potential of fra-2, transgenic mice were generated which over-express fra-2 in a number of tissues. No tumours were evident in any transgenic mice up to 18 months of age, although eye development was severely disrupted in these animals. Corneal abnormalities could be observed histologically as early as embryonic day 15.5 and eyelid fusion failed to occur. Adult eyes were characterized by generalized anterior segment dysgenesis similar to that previously reported in transgenic mice over-expressing transforming growth factor alpha (TGF alpha), and occasionally microphthalmia. Expression of fra-2 was shown to increase following TGF alpha treatment of cells in vitro, suggesting that AP-1 complexes containing Fra-2 contribute to TGF alpha signalling events.

3T3 Cells↗

PubMed1998

A novel T cell-regulated mechanism modulating allergen-induced airways hyperreactivity in BALB/c mice independently of IL-4 and IL-5.

The immunoregulatory functions of IL-4 and IL-5 have identified these cytokines as primary targets for the resolution of airways inflammation and bronchial hyperreactivity in asthma. However, the individual contribution of each of these cytokines and of IL-5-regulated eosinophilia to the induction of airways hyperreactivity in mouse models of asthma remains highly controversial. In this investigation, we have used IL-4- and IL-5-deficient mice of the same genetic background in combination with inhibitory mAbs to these cytokines to identify unequivocally the contribution of these factors to the induction of airways hyperreactivity. Sensitization and aeroallergen challenge of wild-type mice with OVA induced pathological changes to the respiratory epithelium, airways eosinophilia, and hyperreactivity to beta-methacholine. Inhibition of the actions of IL-4 and/or IL-5 did not abolish airways hyperreactivity, and in the case of IL-4-deficient mice pretreated with anti-IL-5 mAb, airways hyperreactivity persisted in the absence of pronounced airways inflammation. Airways hyperreactivity was abolished only by anti-CD4+ mAb treatment. However, aeroallergen challenge of IL-5-/- mice showed that morphologic changes to the airways were critically linked to IL-5 and eosinophilia. This investigation demonstrates the existence in BALB/c mice of a novel CD4+ T cell pathway for modulating airways hyperreactivity. These findings may provide an explanation for the dissociation of airways eosinophilia from the development of airways hyperreactivity observed in some cases of asthma and in animal models of this disease.

Allergens↗

PubMed1998

Developmental expression of messenger RNA levels of the alpha subunit of the GTP-binding protein, Gz, in the mouse nervous system.

There has been recent evidence that Gz may play a role in the transmission of the neurotrophic signal from nerve terminals to the cell bodies [Johanson, S.O., Crouch, M.F., Hendry, I.A., Signal transduction from membrane to nucleus: the special case for neurons, Neurochem. Res. 21 (1996) 779-785]. We examined the developmental expression of the alpha subunit of Gz (Gzalpha) in the peripheral and central nervous systems of the mouse. Our laboratory has developed a quantitative reverse transcription-polymerase chain reaction (RT-PCR) for Gzalpha which makes use of a fragment of the PCR product shortened by 107 base pairs creating a standard which mimics the original RNA. Serial dilutions of the mouse RNA with a constant concentration of mimic RNA were made and the point where equal amounts of product are formed allows accurate measurement of Gzalpha mRNA in the tissue. We have demonstrated that in the developing mouse superior cervical ganglion (SCG), dorsal root ganglion (DRG) and trigeminal ganglion the expression of Gzalpha mRNA is highest perinatally. From 3 weeks of age, in all tissues with the exception of the SCG, Gzalpha mRNA levels fall to lower levels in the adult animal. The developmental pattern of expression of Gzalpha in both the cerebellum and the brain differs from the peripheral nervous system. In the cerebellum, Gzalpha mRNA expression is highest around birth and in the brain it is highest around third postnatal week and then the levels decline as adulthood is approached. These results suggest that the highest level of Gzalpha mRNA is expressed at the time when target tissue innervation is occurring. This further strengthens the hypothesis that Gzalpha is important in the transfer of information from target tissues to the innervating nerve cells.

Animals↗

PubMed1998

Intestinal IgA plasma cells of the B1 lineage are IL-5 dependent.

Two lineages of B cells, designated B1 and B2 cells, have been identified based upon their origins, anatomical distribution, cell surface markers, antibody repertoire and self-replenishing potential. B1 cells are maintained by self-renewal of cells resident in the peritoneal cavity (PerC) and they utilize a limited repertoire of germline V-region genes, mostly directed against ubiquitous bacterial antigens such as phosphoryl choline (PC). B2 cells are replenished from bone marrow precursors and use a larger repertoire of immunoglobulin V-region genes. Whereas most immunoglobulin A (IgA) plasma cells in the intestine derive from B2 lineage precursors in the Peyer's patch, a subpopulation of Per C-derived B1 cells populate the intestinal lamina propria where they mature into IgA plasma cells. In previous in vivo studies we have shown that whereas IgA+ B2 cells are interleukin (IL)-6 dependent, B1 cells are IL-6 independent. In view of the in vitro evidence that IL-5 is also involved in IgA expression, in the studies reported here we have used IL-5-deficient mice to evaluate the role of IL-5 in vivo in IgA expression in the gut. The results demonstrate that although total IgA cell numbers are only marginally depressed in IL-5-deficient mice, there is a marked selective depletion of IgA+ cells of the B1 lineage in the gut and a corresponding depression in the capacity of these mice to mount an intestinal response to a B1 antigen (PC) but not to a B2 antigen (oralbumin; OVA), reflecting intact B2-derived IgA cell function but a defect in the B1 cell contribution to IgA responses in IL-5 deficient mice. Collectively these data demonstrate differential cytokine regulation of subsets of IgA+ cells in the gut in that IgA+ cells of the B2 lineage are IL-6 dependent but IL-5 independent, but B1-derived IgA+ cells are IL-5 dependent and IL-6 independent.

Animals↗

PubMed1998

Regulation of primary Strongyloides ratti infections in mice: a role for interleukin-5.

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.

Animals↗

PubMed1998

Loss of antiviral cytotoxic T-lymphocyte activity during high-level antigen stimulation.

High levels of antigenic stimulation can result in deactivation of CD8+ T cells through a variety of mechanisms, including insufficient T-cell help. In the present study, an adoptive transfer system was established in which ovalbumin (OVA)-specific CD8+ T cells were transferred to irradiated mice infected with a recombinant vaccinia virus encoding OVA (VV-OVA). Prolonged activation of OVA-specific CD8+ T cells resulted in a proliferative block in these cells, although cytotoxic function was maintained. Unlike naive and recently activated OVA-specific T cells, these nonproliferative cytotoxic CD8+ T cells did not have antiviral activity following further transfer to mice infected with VV-OVA. Provision of interleukin-2 (IL-2) at the site of virus infection using a recombinant virus encoding antigen and IL-2, as well as the addition of helper T cells, had no effect on the generation of these dysfunctional T cells. Thus, there was no evidence that lack of T-cell help was responsible for CD8+ T-cell deactivation in this model.

Animals↗

PubMed1998

Interleukin-5-producing CD4+ T cells play a pivotal role in aeroallergen-induced eosinophilia, bronchial hyperreactivity, and lung damage in mice.

Although activated CD4+ T cells have been implicated in the pathogenesis of asthma, the direct contribution of this leukocyte to the induction of aeroallergen-induced bronchial hyperreactivity and lung damage is unknown. In the present investigation, we have used a model of allergic airways inflammation, which displays certain phenotypic characteristics of late-phase asthmatic responses, together with interleukin-5-deficient (IL-5-/- ) mice and donor antigen-specific CD4+ TH2-type cells to obtain unequivocal evidence for a role of this T lymphocyte in the pathophysiology of allergic airways inflammation. Antigen-primed CD4+ T cells and CD4- cells (CD4+-depleted population) were purified from the spleens of ovalbumin (OVA)-sensitized wild-type mice and adoptively transferred to OVA-sensitized and nonsensitized IL-5-/- mice. In vitro stimulation of the purified cell populations with OVA resulted in the secretion of IL-4 and IL-5, but not interferon-gamma, from the CD4+ T cells, indicating that they were of the TH2 type. In contrast, interferon-gamma, but not IL-4 and IL-5, was produced by the CD4- T cells. The CD4+ TH2-type cells (but not the CD4 cells) reconstituted aeroallergen (OVA)-induced blood and airways eosinophilia, lung damage, and airways hyperreactivity to 1-methacholine in IL-5-/- mice. The reconstitution did not require prior sensitization of the mice, but it did not occur if they were aerosolized with saline instead of OVA. The circulating levels of OVA-specific -IgE and -IgG1 were not significantly altered by the adoptive transfer of either cell population. These investigations establish that IL-5-secreting CD4+ TH2-type cells play a pivotal role in generating blood and airways eosinophilia and in the subsequent development of bronchial hyperreactivity and lung damage that occurs in response to aeroallergens.

Adoptive Transfer↗

PubMed1998

Use of polymerase chain reaction to diagnose a natural outbreak of mouse hepatitis virus infection in nude mice.

The enormous cost of eliminating mouse hepatitis virus (MHV) from a mouse colony demands that a confirmed etiologic diagnosis be made to justify the necessary remedial action. We describe an outbreak of MHV in nude mice in which histopathologic findings provided a presumptive diagnosis, but results of serologic testing of affected nude mice and immunocompetent sentinels were negative. Results of transmission electron microscopy of liver specimens from affected mice were equivocal. Confirmation of the etiopathogenesis was eventually provided by reverse transcriptase-polymerase chain reaction (RT-PCR), using primers with nested sequences directed to two separate but highly conserved regions of the MHV genome. This procedure detected MHV in the liver of an affected nude mouse and in a sentinel, although in the latter a positive result was obtained only because of the increased sensitivity of nested primers used in a second round of amplification. Virus was not detected in cell lines that had been injected into the mice, and the source of the outbreak was not found. These results indicate the applicability of RT-PCR for detecting MHV in a field situation while also illustrating that conventional, complementary techniques still have an essential role in reaching a diagnosis. It is recommended that specimens should be taken for histologic examination and serologic testing, as well as for molecular studies when MHV infection is suspected.

Animals↗

PubMed1997

Relationship between interleukin-5 and eotaxin in regulating blood and tissue eosinophilia in mice.

The mechanism of cooperation between IL-5 and eotaxin for the selective accumulation of eosinophils at sites of allergic inflammation is unknown. In this investigation we have used IL-5 deficient mice to define the relationship between this cytokine and eotaxin in the regulation of blood eosinophilia and eosinophil homing and tissue accumulation. Both IL-5 and eotaxin could independently induce a rapid and pronounced blood eosinophilia in wild type mice when administered systemically. In contrast, only eotaxin induced a pronounced blood eosinophilia in IL-5 deficient mice. The eosinophilic response induced by intravenous eotaxin in wild type mice did not correlate with a significant reduction in the level of bone marrow eosinophils, whereas intravenous IL-5 resulted in depletion of this store. These results suggest the existence of two mechanisms by which eosinophils can be rapidly mobilized in response to intravenous eosinophil chemoattractants; first, mobilization of an IL-5 dependent bone marrow pool, and second, an eotaxin-induced sequestration of eosinophils from tissues into the blood. Subcutaneous injection of eotaxin induced a local tissue eosinophilia in wild type mice but not in IL-5 deficient mice. Furthermore, tissue eosinophilia in wild type mice, but not in IL-5 deficient mice, was enhanced by adoptive transfer of eosinophils or the administration of intravenous IL-5. However, pretreatment of IL-5 deficient mice with intraperitoneal IL-5 for 72 h restored eosinophil homing and tissue accumulation in response to subcutaneous eotaxin. We propose that eotaxin secreted from inflamed tissue may play an important role in initiating both blood and tissue eosinophilia in the early phases of allergic inflammation. Furthermore, IL-5 is not only essential for mobilizing eosinophils from the bone marrow during allergic inflammation, but also plays a critical role in regulating eosinophil homing and migration into tissues in response to eotaxin and possibly other specific chemotactic stimuli.

Adoptive Transfer↗

PubMed1997

Eosinophils are not required for the rejection of neovascularized fetal pig proislet xenografts in mice.

The rejection of neovascularized pig proislet (islet precursor) xenografts in mice is a CD4 T cell-dependent process involving invasion of the graft site mainly by host CD4 T cells and eosinophils. We previously identified CD4 T cell-dependent enhancement of intragraft IL-3, IL-4, and IL-5 mRNA expression during acute xeno-rejection in CBA/H recipient mice. In the present study we investigated the role of each cytokine and the involvement of eosinophils in the rejection of pig proislet xenografts using cytokine gene knockout mice (IL-4 -/- and IL-5 -/-) and the treatment of transplant recipients with anti-IL-3 mAb. In IL-4 -/- mice, IL-5 -/- recipient animals, and anti-IL-3 mAb-treated CBA/H mice, eosinophil accumulation at the transplant site was inhibited or ablated, but the kinetics of xenograft rejection was unaltered. Prolonged xenograft survival was only achieved in anti-CD4 mAb-treated mice and consistently correlated with the absence of intragraft IL-3, IL-4, and IL-5 mRNA enhancement. Together these findings indicate that neither IL-3, nor IL-4, nor IL-5 individually plays an obligatory role in the rejection process. The cytokine mRNA profile correlating with the lack of eosinophil recruitment was variable; the data suggest that IL-4 regulates eosinophil involvement in the xeno-rejection reaction indirectly via effects on IL-5 and IL-3 transcript expression. There is also suggestive evidence that IL-5 may influence IL-3 and IL-4 mRNA expression via feedback inhibition. Eosinophils, therefore, do not play an essential role in the rejection of neovascularized pig proislet xenografts in mice.

Animals↗

PubMed1997

Eosinophilia, parasite burden and lung damage in Toxocara canis infection in C57Bl/6 mice genetically deficient in IL-5.

C57Bl/6 mice genetically deficient in interleukin (IL)-5 (IL-5-/-) and mice with the normal IL-5 gene (IL-5+/+) were infected with embryonated eggs of Toxocara canis. IL-5+/+ mice developed a marked eosinophilia in their peripheral bloods and bone marrows after infection. In contrast, the number of eosinophils at these sites actually decreased during the acute phase of infection in IL-5-/- mice. A smaller number of eosinophils infiltrated the lung, liver, heart and skeletal muscle of infected IL-5-/- mice than those of infected IL-5+/+ mice. Eosinophils were not produced in cultures of bone marrow cells from either IL-5+/+ or IL-5-/- mice which were stimulated with excretory secretory antigen of T. canis larvae. The capacity of cells from the bone marrow to differentiate into eosinophils when stimulated in vitro with recombinant murine IL-5 was the same whether the cells were from IL-5+/+ or IL-5-/- mice. Taken together, these results show that an IL-5-like molecule is not produced by the T. canis larvae and that IL-5 produced by host cells is solely responsible for the eosinophilia in mice infected with this nematode. The number and location of T. canis larvae were not altered in the absence of IL-5. In contrast, lung damage in infected IL-5-/- mice was less extensive than that in infected IL-5+/+ mice, although structures resembling Charcot-Leyden crystals were seen in the lungs of both IL-5+/+ and IL-5-/- mice. These results suggest that eosinophils play a role in the pathology in mice infected with T. canis.

Animals↗

PubMed1997

Enhancement of the specific mucosal IgA response in vivo by interleukin-5 expressed by an attenuated strain of Salmonella serotype Dublin.

It has been shown that cytokines have potential as therapeutic adjuvants in vaccination. Interleukin-5 (IL-5) is a cytokine that regulates antibody production, in particular enhancing IgA production by activated mucosal B cells. This study examined the expression of a cloned cytokine gene encoding murine IL-5 (mIL-5) by an attenuated aroA strain (SL5631) of Salmonella serotype Dublin. The resulting strain, SL5631(pTRXFUS-mIL-5), expressed mIL-5 as a fusion with thioredoxin as demonstrated by immunological and biological assays. When strain SL5631(pTRXFUS-mIL-5) was used as a live vaccine in BALB/c mice, it colonised and multiplied at higher levels in spleens and livers than the strain carrying the empty plasmid. A reduction in invasiveness of SL5631(pTRXFUS-mIL-5) was observed in in-vitro invasion assays. Enhanced IgA response against salmonella LPS in mucosal secretions and enhanced IgA and IgG responses were detected by ELISA and ELISPOT methods in sera of mice immunised with the strain expressing mIL-5. Results with IL-5-deficient mice showed that the enhanced IgA response was due to Salmonella-expressed mIL-5 rather than endogenous mIL-5.

Animals↗