IFNγ and IL-12 Restrict Th2 Responses during Helminth/Plasmodium Co-Infection and Promote IFNγ from Th2 Cells

Parasitic helminths establish chronic infections in mammalian hosts. Helminth/Plasmodium co-infections occur frequently in endemic areas. However, it is unclear whether Plasmodium infections compromise anti-helminth immunity, contributing to the chronicity of infection. Immunity to Plasmodium or helminths requires divergent CD4⁺ T cell-driven responses, dominated by IFNγ or IL-4, respectively. Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines. Whether such plasticity occurs during co-infection is unclear. In this study, we observed reduced anti-helminth Th2 cell responses and compromised anti-helminth immunity during Heligmosomoides polygyrus and Plasmodium chabaudi co-infection. Using newly established triple cytokine reporter mice (Il4^gfpIfng^yfpIl17a^FP635), we demonstrated that Il4^gfp+ Th2 cells purified from in vitro cultures or isolated ex vivo from helminth-infected mice up-regulated IFNγ following adoptive transfer into Rag1^–/– mice infected with P. chabaudi. Functionally, Th2 cells that up-regulated IFNγ were transcriptionally re-wired and protected recipient mice from high parasitemia. Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells. Finally, blockade of IL-12 and IFNγ during co-infection partially preserved anti-helminth Th2 responses. In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection. Consequently, co-infection with Plasmodium spp. may contribute to the chronicity of helminth infection by reducing anti-helminth Th2 cells and converting them into IFNγ-secreting cells.

Approximately a third of the world’s population is burdened with chronic intestinal parasitic helminth infections, causing significant morbidities. Identifying the factors that contribute to the chronicity of infection is therefore essential. Co-infection with other pathogens, which is extremely common in helminth endemic areas, may contribute to the chronicity of helminth infections. In this study, we used a mouse model to test whether the immune responses to an intestinal helminth were impaired following malaria co-infection. These two pathogens induce very different immune responses, which, until recently, were thought to be opposing and non-interchangeable. This study identified that the immune cells required for anti-helminth responses are capable of changing their phenotype and providing protection against malaria. By identifying and blocking the factors that drive this change in phenotype, we can preserve anti-helminth immune responses during co-infection. Our studies provide fresh insight into how immune responses are altered during helminth and malaria co-infection.

Fatty acid profile of fillet, liver and mesenteric fat in tilapia (<i>Oreochromis niloticus</i>) fed vegetable oil supplementation in the finishing period of fattening

Abstract. Tilapia (Oreochromis niloticus) previously reared on a commercial feed were shifted to 3 experimental diets with added 5 % of soybean, linseed oil or fish oils, for 42 days as a finishing diet, according to literature recommendations. Fillet, liver and mesenteric fat total lipid fatty acid composition was determined and evaluated taking health and dietary recommendations into consideration. It was found that dietary vegetable oil fatty acids are effectively incorporated into tilapia hepatic and muscular total lipids, but have no pronounced effect on further fatty acid metabolism, in particular on the n-3 fatty acids. Liver was found to sensitively indicate elevated dietary lipid intake, as proven by its higher, most probably endogenous palmitate synthesis. Based on our results the application of vegetable oils to partially substitute fish oil for tilapia can be recommended in relation to the most important dietary lipid quality indicators.

Global transcriptional analysis of primitive thymocytes reveals accelerated dynamics of T cell specification in fetal stages

T cell development constitutes a multistage process allowing the dissection of events resulting in cellular commitment and functional specification in a specialized microenvironment. This process is guided by the appropriate expression of regulatory genetic factors like transcriptional activators or repressors which are, in part, dependent on instructive signals of the microenvironment. To date, it remains unclear whether exactly the same genetic mechanism acts in adult compared to fetal T cell development. In order to directly compare T cell commitment during adult and fetal differentiation, we isolated subsequent stages of intrathymic subpopulations starting with early canonical T cell progenitors up to irreversibly committed T cell precursors. The genome-wide analysis revealed several distinct gene clusters with a specific pattern of gene regulation for each subset. The largest cluster contained genes upregulated after transition through the most primitive pool into the next transitory population with a consistently elevated expression of elements associated with ongoing T cell fate specification, like Gata3 and Tcf7, in fetal progenitors. Furthermore, adult and fetal T cell progenitors occupied distinct "transcriptional territories" revealing a precise land map of the progression to final T cell commitment operating in different developmental windows. The presence and/or elevated expression of elements associated with an ongoing establishment of a T cell signature in the most primitive fetal subset is highly suggestive for an extrathymic initiation of T cell specification and underlines the fundamental differences in fetal versus adult lymphopoiesis.

Differentiation of mycoplasma gallisepticum strains using molecular methods

Increasing use of Mycoplasma gallisepticum (MG) live vaccines has led to a need for the differentiation of MG strains. The MG strains MK-7, MS-16, S6, FS-9 and R strains and the MG live vaccine strain F were compared by random amplification of polymorphic DNA (RAPD) in this study. Using RAPD, different patterns were found among the MG strains. In addition to this, we examined the differentiating potential of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) primers targeted at the crmA, crmB, crmC, gapA, mgc2 and pvpA genes encoding cytadherence-related surface proteins. These proteins may take part in the pathogenesis of MG-induced disease. Differentiation of strain F is based on the identification of restriction enzyme sites in the PCR amplicons. Using HphI enzyme, crmC PCR amplicons produced different RFLP patterns. Digestion of amplicons of gapA-specific PCR with MboI enzyme also produced distinct patterns. Differences were observed among strains R and F by digestion of mgc2 PCR amplicons with HaelIl and VspI enzymes and digestion of pvpA PCR amplicons with AccI, PvulI and ScrFI endonucleases. This method can be used for the rapid differentiation of vaccine strain from wild strains. Differentiation of MG strains is a great advantage for diagnosticians or practitioners and it is useful for epidemiological studies.

Detection of Mycoplasma bovis with an improved pcr assay

A Mycoplasma bovis species-specific PCR assay has been developed with improvement of a previously described method (Ghadersohi et al., 1997). This test and its semi-nested version (Hayman and Hirst, 2003) did not function at all in our hands. A new reverse primer (Mbr2) was designed using previously published sequence data. For testing specificity, DNA was extracted from the most frequently occurring mycoplasma species and bacteria of bovine origin. The new PCR detected only Mycoplasma bovis. Moreover, no cross-reaction was observed with the genetically closest relative species, M. agalactiae. The target organism could be detected in a dose as low as 150 CFU ml(-1) in broth cultures using ethidium-bromide-stained agarose gels.

Cytokine networks and corticosteroid receptors

The role of the inflammatory cytokines on glucocorticosteroid binding (GCSB) and glucocorticosteroid receptor (GR) level was studied. We incubated a B cell line--CESS--, a promonocytic cell line--U937--and a hepatoma cell line--HepG2--in the presence of varying concentrations of IL-1 beta, IL-6 and TNF-alpha for 24 hours. Glucocorticosteroid binding was determined by the method of "whole cell uptake," and characterized by Scatchard analysis. A considerable increase in the glucocorticosteroid binding was induced by all the three cytokines. Northern analysis of the glucocorticoid receptor expression demonstrates that the action of the cytokines is likely not pretranslational. Present data suggest that local imbalance in the ratio of these three cytokines in different pathological cases might influence the glucocorticosteroid sensitivity of the lymphocytes, monocytes and hepatocytes as target cells.

Enhancement of interleukin-6 production by fibrinogen degradation product D in human peripheral monocytes and perfused murine liver

The effect of fibrinogen degradation products D and E (FDP-D, FDP-E) on IL-6 production in perfused mouse livers and peripheral monocytes is studied. Similarly to bacterial endotoxin FDP-D is highly potent to augment the IL-6 production measured in perfused mouse livers, while FDP-E is not stimulatory. FDP-D but not FDP-E is able to stimulate the in vitro IL-6 production of human peripheral monocytes, as well. Plasmin alone is almost ineffective on IL-6 production both in perfused livers and monocytes. Our findings suggest a direct positive feedback circuit, among fibrinogen, FDP and IL-6.

The effect of WSEWS pentapeptide and WSEWS-specific monoclonal antibodies on constitutive and IL-6 induced acute-phase protein production by a human hepatoma cell line, HEPG-2

Interleukin-6 receptor (IL-6R) is a member of the cytokine receptor superfamily characterised by the obligatory presence of WSXWS (Trp-Ser-X-Trp-Ser) sequence motif near the transmembrane domain. To more clearly understand the role of this motif, we treated the HepG2 hepatoma cell line with synthetic WSEWS peptide (E is glutamic acid) and checked the spontaneous and IL-6-induced production of acute-phase protein fibrinogen and C1-inhibitor (C1-INH). The peptide revealed a definitely stimulatory effect both on the constitutive synthesis of C1-INH and on the IL-6-induced fibrinogen synthesis of HepG2 cells. Monoclonal antibody specific for WSEWS pentapeptide was stimulatory for the spontaneous secretion of both fibrinogen and C1-INH. However, the IL-6-induced elevations of these acute-phase proteins were oppositely regulated, since the anti-WSEWS monoclonal antibody was inhibitory on the production of fibrinogen induced by IL-6 but strongly augmented the IL-6 induced production of C1-INH. Our study indicates that the WSEWS motif is critical in the effect of IL-6 on the acute-phase protein production influencing either the ligand binding by the WSEWS-containing receptor molecule or the signal transduction.

Separate regulation of a membrane protein, gp130, present in receptor complex specific for interleukin-6 and other functionally related cytokines

In addition to specific ligand binding elements, receptor assembly for interleukin(IL)-6, oncostatin-M, leukaemia inhibitory factor, ciliary neurotrophic factor and IL-11 includes an additional unit, gp130. This molecule is a transmembrane glycoprotein of 130 kDa. In this paper, reviewing molecular, biochemical and functional data on gp130, we describe the dissimilar action of IL-3 on the expression of the binding unit of the IL-6 receptor and that of gp130. According to FACS studies, resting basophils express only IL-6 receptors and no gp130 molecules on the plasma membranes. After incubation with IL-3, the surface appearance and de novo transcription of gp130 was shown by FACS and mRNA polymerase chain reaction analysis.

Modulation of glucocorticosteroid binding in human lymphoid, monocytoid and hepatoma cell lines by inflammatory cytokines interleukin (IL)-1 beta, IL-6 and tumour necrosis factor (TNF)-alpha

In order to elucidate the role of the inflammatory cytokines in regulating glucocorticosteroid binding (GCSB) and glucocorticosteroid receptor (GR) level we incubated a B-cell line (CESS), a promonocytic cell line (U937) and a hepatoma cell line (HepG2) in the presence of varying concentrations of IL-1 beta, IL-6 and TNF-alpha for 24 h. Glucocorticosteroid binding was determined by the method of 'whole cell uptake', and the cellular appearance of the glucocorticosteroid receptor was detected by immunocytochemistry. A rise in the glucocorticosteroid binding was induced by all three cytokines. The increase in level of glucocorticosteroid receptors in the cells shown by immunocytochemistry was much more pronounced. However, antagonistic effects were demonstrated by both methods between IL-6 and TNF-alpha, and between IL-1 beta and TNF-alpha when they were applied simultaneously, in U937. Present data suggest that local imbalance in the ratio of these three cytokines in different pathological cases might influence the glucocorticosteroid sensitivity of the lymphocytes, monocytes and hepatocytes as target cells.

Histamine modulates the interleukin-6-regulated acute phase protein synthesis in cultured murine hepatocytes

Murine hepatocytes cultured in the presence of human recombinant interleukin-6 (IL-6) show increased synthesis of fibrinogen and complement component C3 by the addition of histamine. No similar effect was achieved when murine hepatocytes were treated with histamine alone or with histamine and interleukin-1 alpha together. Using histamine-1 (H1) and H2 receptor antagonists a prevalence of histamine H1 receptor in the enhancement of IL-6-induced effect is suggested.

[Molecular genetic, laboratory and clinical study of serum amyloid P]

Studying the gene polymorphism of serum amyloid P a common constituent of amyloid deposits two restriction fragment length polymorphism patterns were found among Hungarian rheumatoid arthritis (RA), juvenile rheumatoid arthritis (JRA), systemic lupus erythematosus (SLE) patients and healthy controls. Although no direct connection between DNA polymorphism and the frequency of amyloidosis in three patient groups was found, a marked predominance of the heterozygosity in all studied groups has been described. Authors found close correlation between the serum levels of SAP and CRP in juvenile rheumatoid arthritis, but failed to find the same correlation in SLE and healthy controls. Moreover, the serum level of CRP of heterozygous patients were significantly higher than that of homozygous patients within the juvenile rheumatoid arthritis patient groups.

[Active immunization against tick-borne encephalitis in the elderly]

30 healthy young persons and 19 healthy aged people (between 60-75 years) were vaccinated against tick-borne meningoencephalitis virus. The antibody production of the young people was compared to that of the aged ones following vaccination. It has been found that the antibody production of the aged people was delayed, and more elderly people than young ones showed an increase of the IgM-bearing lymphocytes after vaccination. The morphological changes of the circulating lymphocytes were identified with electron microscope. The presence of cytoplasmic inclusions called parallel tubular arrays could be observed in the course of immunization. The inclusions were not found before vaccination, and it is suggested that the inclusions are related to the in-vivo antigen stimulation.

Age-related morphological changes in lymphocytes as a model of aging

The same age-related morphological changes have been observed in the lymph node and spleen lymphocytes of old untreated Wistar rats and CBA/Ca mice. The same age-related changes were also observed in the peripheral lymphocytes of healthy humans. The most important changes were seen in the mitochondria of the lymphoid cells. They were sometimes swollen; the mitochondrial cristae disappeared and were replaced by myelin-like forms or filamentous structures. The mitochondrial changes developed only in non-labelled lymphoid cells, presumably the T cells. It is suggested that lymphocytes be used as a morphological model for the study of aging and its modification.

The influence of influenza vaccinations on human peripheral blood lymphocytes relating to aging

Twenty healthy, aged more than 60 years were compared to 20 healthy young volunteers less than 40 years following influenza vaccinations. 0.5 ml, 10 U. of killed influenza vaccine Hong Kong B/873 was repeatedly given intramuscularly. Blood was collected before the vaccination, 6 days, respectively 6 weeks after vaccinations. The purified venous blood lymphocytes were examined by immunohistological and sheep erythrocyte rosette-forming methods. The absolute number of T and B lymphocyes was counted. It has been found that increase of IgG-bearing cells was higher in young persons, than in the elderly both in the first and in the revaccination. The absolute number of IgM-bearing lymphocytes increased in the aged after influenza vaccinations. The vaccine had no significant effect on the absolute number of IgA-bearing lymphocytes. The absolute number of T lymphocytes participating in the immune reaction showed a transitory increase solely in young persons. Experiments aiming to demonstrate the reduced activation of B lymphocytes in the elderly with the influenza vaccinations. It can be concluded, that the proliferation ability of the immunoglobulin-bearing B cells and T cells is reduced due to old age.

Electronmicroscopical and immunoelectronmicroscopical examination of the lymphocytes of young and old people after influenza vaccination

Authors examined the lymphocytes of young and old individuals before, 6 days and 6 weeks after influenza vaccination. Vaccination was carried out with killed Influenza B/Hong-Kong virus. Electronmicroscopic structure of the lymphocytes and membrane bound surface IgG and IgM were studied. Membrane bound surface IgG and IgM were seen on the small lymphocytes and on the membrane of the medium-sized lymphocytes in young and aged individuals before and after vaccination. In both age groups intracytoplasmic tubuloreticular structures were seen in the lymphocytes. These findings were not age dependent alterations. Age dependent changes could be detected on the mitochondria of the lymphoid cells. The mitochondrial crysts in aged individuals disappeared and were replaced by myelin-like forms or by faint density substance. The mitochondrial changes were present before vaccination and after vaccination in non labelled, presumably T lymphocytes. The injury of the mitochondrium can influence the function and the proliferative capacity of the cells.

Autoantibodies in aged individuals

Authors determined in 282 individuals autoantibodies in 132 T and B lymphozytes. Theirs results were as follows: 1. The frequency of the presence of autoantibodies increases with age. 2. In the presence of autoantibodies the absolute T and B lymphocyte counts of aged persons markedly decrease; the absolute T and B lymphozyte counts of young adult people do not change by existing autoantibodies. 3. There is a significant difference between the absolute T cell counts of aged and young adult age groups, both age-groups having autoantibodies. 4. Comparing the frequency of occurence of autoantibodies in aged healthy persons and in aged ones with cardiovascular changes and being in the habit of smoking and consuming alcohole, respectively, a significant difference could be demonstrated; in the latter group the frequency was much higher.

Immuno-electronmicroscopic studies after influenza vaccination of young and old individuals

Authors examined the lymphocytes of young and old individuals after influenza vaccination. They stated that membrane bound surface IgG and IgM were detectable on the lymphocytes and occasionally on lymphoblasts in both the old and young age groups. In both age-groups intracytoplasmic tubulo-reticular structures (TRS) were seen in the lymphocytes and lymphoblasts. In young individuals TRS was present in the peroxidase positive cells, in the contrary in old persons TRS was never found in cells with surface immunoglobulins. In the TRS themselves peroxidase positive IgG and IgM could be detected.

Age-related change of the absolute number of IgG-, and IgM-bearing B-lymphocytes and T-lymphocytes in human peripheral blood following influenza vaccination

The absolute number of IgG-, and IgM-bearing B lymphocytes and of T lymphocytes was determined in the peripheral blood of 12 old (over 60 years) and 11 young (20 to 40 years) healthy persons before vaccination and 6 days and 6 weeks, respectively after vaccination. It has been found that as opposed to an approximately fivefold increase of IgG bearing cells in young persons, the increase did hardly reach double of the original value in old individuals. The absolute number of T lymphocytes participating in the immune reaction showed a transitory increase in young persons, while a gradual decrease has been observed in old individuals. In healthy elderly persons the administration of 10 U Honkong 5/72-B killed influenza virus as in vivo antigen stimulus resulted in a reduced proliferation of IgG carrier lymphocytes participating in antibody production.

Effect of the depletion on brain noradrenaline on the plasma FSH and growth hormone levels in ovariectomized rats

The electrolytic lesion of locus coeruleus reduced the hypothalamic noradrenaline (NE) content to 28% of the control values and resulted in a marked decrease of the plasma FSH level in ovariectomized rats before puberty. The local microinjection of 6-OH-dopamine into the locus coeruleus led to a reduction in the hypothalamic NE content to 21% of the control level and induced a decrease of the compensatory ovarian hypertrophy and that of the plasma FSH level. The electrolytic lesion of the locus coeruleus or the 6-OH-dopamine treatment failed to influence the plasma growth hormone (GH) level. The observations support the hypothesis that ventral noradrenergic projection is involved in controlling the pituitary FSH secretion.

Nuclear RNA content and synthesis in anterior pituitary in intact, castrated and androgen sterilized rats

The content and uridine incorporation into nuclear RNA of anterior pituitary gland was studied in vitro in intact, castrated and neonatally testosterone treated rats of both sexes. In female rats a higher RNA content and a lower uridine incorporation rate could be observed than in males. The castration resulted in a marked increase of RNA content and uridine incorporation in male rats. Ovariectomy was followed by a decrease of RNA content which was accompanied by an increase of incorporation rate. Estradiol administration produced a biphasic change of RNA content and uridine incorporation in ovariectomized rats. From these findings a repressive action of estrogens on the nuclear RNA synthesis may be suggested. Neonatal testosterone treatment resulted in alterations of RNA synthesis which could be observed in both sexes.