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Results for “Immune function”

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PubMed2004

Potential involvement of rainbow trout thrombocytes in immune functions: a study using a panel of monoclonal antibodies and RT-PCR.

The functional relationship between fish and mammalian thrombocytes is relatively unknown. In this study, a panel of monoclonal antibodies (mAbs) was used to investigate the functional properties of rainbow trout thrombocytes. The mAbs recognize cell-surface molecules on thrombocytes with molecular weights ranging from 17 to 160 kDa. Flow cytometric and immuno-electron microscopic analyses demonstrate that these molecules are expressed at different levels and that surface expression increased upon activation with bovine collagen. Two of these cell-surface molecules (17 and 21 kDa) were directly involved in collagen-induced aggregation of thrombocytes since aggregation was blocked upon pre-treatment with mAbs that recognize the two surface markers. Interestingly, the percentage of thrombocytes in blood increased after stimulation using different antigens. The transcriptional profile of trout thrombocytes was then examined after immuno-magnetic enrichment using the described mAbs to assess potential roles of trout thrombocytes in immune functions. Trout thrombocytes express components of the MHC class Ia pathway, IL1beta, TNFalpha, TGFbeta, the interleukin receptor common gamma chain as well as CXC and CC chemokines. MHC class IIB and TNFalpha were expressed at low levels in resting thrombocytes. No evidence was found for the expression of TCRalphabeta, Ig heavy chain, CD8alpha or CK1 mRNA. Taken together, these results suggest that rainbow trout thrombocytes express molecules involved in activation, aggregation and genes encoding proteins, that are involved in antigen presentation and immune regulation.

Animals↗
PubMed1999

Effects of carotenoids on human immune function.

Many epidemiological studies have shown an association between diets rich in carotenoids and a reduced incidence of many forms of cancer, and it has been suggested that the antioxidant properties of these compounds are a causative factor. Attention has focused on the potential role of one specific carotenoid, beta-carotene, in preventing cancer, and numerous publications have described in vitro experiments and animal studies which suggest that not only can this carotenoid protect against the development of cancer, but also several other chronic diseases. Since the immune system plays a major role in cancer prevention, it has been suggested that beta-carotene may enhance immune cell function. Several human trials, using dietary beta-carotene supplementation with a wide range of intakes, have been undertaken to address this hypothesis. The general conclusion of these studies is that this compound can enhance cell-mediated immune responses, particularly in the elderly. The present article will review some of these human studies and, hopefully, complement the reviews of other authors associated with the present symposium, some of whom will also describe work in this area. Potential mechanisms for the effects of carotenoids on immune function will also be reviewed. Finally, possible reasons for the failure of three major prospective studies to demonstrate a beneficial effect of beta-carotene supplementation on lung cancer risk will be discussed.

Antioxidants↗
PubMed1989

The effects of 9-ene-tetrahydrocannabinol on hormone release and immune function.

We investigated effects of 9-ene-tetrahydrocannabinol (THC) on endocrine and immunological function. Seventeen male volunteers entered into a double blind, randomized study to receive oral THC (10 mg t.i.d. for 3 days and on the morning of the fourth day) or placebo, after at least 2 weeks of abstinence. Plasma prolactin, ACTH, cortisol, luteinizing hormone and testosterone were not altered during or after THC, compared with baseline concentrations. Tests of lymphocyte function showed no differences compared to baseline between THC and placebo groups. As the relatively low dosing regimen of THC (10 mg t.i.d.) resulted in no alterations, another group of 6 men were administered higher doses of THC by inhalation (18 mg/marijuana cigarette) following the same dosing regimen. No endocrine or immunological alterations were observed. When the subjects were grouped according to their history of THC use prior to admission, heavy THC users had lower prolactin concentrations than light users. No differences were observed in concentrations of other hormones or in tests of immune function.

Adult↗
PubMed1999

[Effect of beta-endorphin on plasma sialic acid level in rats and the relationship with the immune function].

With the use of beta-EP microinjection into the central nervous system, spectrophotometrical analysis and immunochemical method we studied the effect of beta-Endorphin (beta-EP) on plasma sialic acid (SA) level. The results indicate: (1) The plasma SA level was significantly decreased after microinjection of beta-EP into the lateral ventricle (LV); (2) When beta-EP was microinjection into nucleus arcuatus (ARC), the plasma SA level was significantly decreased (P < 0.05). This effect can be blocked by i.v. atropine or vagotomy; (3) Microinjection of beta-EP into ARC can cause the increase of CD3, CD4 and CD4/CD8, while CD8 was decreased. The above results suggest that the possible mechanism underlying the decrease of plasma SA level is mediated by cholinergic muscarinic receptor, and the cellular immune function is enhanced.

Animals↗
PubMed1997

The monitoring biomarker for immune function of lymphocytes in the elderly.

In this paper, we determined the number of peripheral blood lymphocytes (PBL) in the elderly and their proliferative response to PHA (Phytohemagglutinin). The data showed that the PBL number decreased with age. For the young group: 1680.0 +/- 644.7/microliters; the 60-69 years old group: 1284.0 +/- 492.3/microliters; the 70-79 years old group: 987.5 +/- 309.1/microliters, P < 0.05. The OD (optical density) value measured by MTT method for proliferative response of PBL in the elderly was 0.15 +/- 0.08, which was lower than the young group 0.18 +/- 0.05. Also, an apparent decline of soluble IL-2 receptor (sIL-2R) release from activated PBL in old people was found. The results suggested that the changes of PBL number and sIL-2R level could be considered as an indication of immune function of lymphocytes in the elderly.

Adult↗
PubMed2003

Depression and HIV infection: impact on immune function and disease progression.

Can psychological factors, such as depression, affect human immunodeficiency virus progression? HIV infection is viewed as a chronic illness in which those infected often confront a number of emotional challenges and physical health and disease-related issues. Over the past 20 years, there has been increasing evidence that depression and other mood-related disturbances are commonly observed among HIV-positive individuals. There is also mounting data showing that depressive symptoms might further impact upon specific elements of immune system functioning and influence quality of life and health status. This paper will highlight studies examining the prevalence of depression during HIV infection and review some of the evidence examining the impact of depressive symptoms on immune function and HIV disease progression.

CD4 Lymphocyte Count↗
PubMed1994

Immune function of patients receiving recombinant human interleukin-6 (IL-6) in a phase I clinical study: induction of C-reactive protein and IgE and inhibition of natural killer and lymphokine-activated killer cell activity.

Interleukin-6 (IL-6) is a cytokine that acts on a variety of cell types, including myeloid progenitor cells and B and T lymphocytes. It has been found to activate cytotoxic T cells and natural killer (NK) cells and to induce T-cell-mediated antitumour effects in animal models. In a phase I clinical trial of recombinant human IL-6, 20 patients with advanced cancer were entered to receive daily subcutaneous injections of IL-6 over 7 days followed by a 2-week observation period and another 4 weeks of daily IL-6 injections. Doses varied between 0.5 microgram/kg and 20 micrograms/kg body weight and immune functions were monitored throughout. At all dose levels IL-6 administration led to a marked increase in serum levels of C-reactive protein and a moderate rise in complement factor C3. The proportions of CD4, CD8 or HLA-DR lymphocytes in peripheral blood did not alter with IL-6 treatment nor did the in vitro proliferation of peripheral blood mononuclear cells induced by either phytohaemagglutinin, pokeweed mitogen or fixed Staphylococcus aureus. By contrast, NK cell activity, lymphokine-activated killer (LAK) cell activity and proliferation induced by in vitro culture with interleukin-2 (IL-2) were suppressed at doses exceeding 2.5 micrograms/kg. Serum IgE levels were consistently elevated over the IL-6 dose range but IgM, IgG and IgA levels were unaffected. In summary there is a dose-dependent induction of acute-phase proteins by in vivo IL-6 treatment. At higher IL-6 doses there is a suppressive effect on NK and LAK activity measured in vitro. IL-6 may thus be useful in combination cytokine therapies that seek to suppress LAK and favour cytotoxic T lymphocyte responses. The rise in IgE levels in response to IL-6 was unexpected and suggests a more pivotal role than previously known for the control of IgE production; this could include IgE-related diseases.

Antibodies, Antinuclear↗
PubMed1995

Stimulatory effect of saponin from Panax ginseng on immune function of lymphocytes in the elderly.

We used the saponin Rg1 extracted from Panax ginseng to study its effects on lymphocytes of 10 young and 19 elderly persons. The proliferative response of lymphocytes cocultured for 72 h with PHA and saponin was measured by using MTT method and the 3H-TdR incorporation procedure. PHA and Rg1 had stimulative effects on the phenotype of lymphocytes (P < 0.001). Rg1 also increased the fluidity of lymphocyte membrane of the aged (P < 0.001). The CD25 and CD45RA positive cells of lymphocytes in the elderly were lower than those of the young people, 8.6% +/- 2.7% vs 10.43% +/- 3.5%; 20.95% +/- 15.5% vs. 50.86% +/- 4.2%, respectively. More CD45RO positive cells (41.5% +/- 13.9%) than CD45RA positive cell lymphocyte populations were seen in the aged. The CD45RO positive cells of the young people were 39.63% +/- 3.2%. We discussed the cause of declined immune function of lymphocytes of aged person and the mechanism of the effect of P. ginseng on lymphocytes.

Aged↗
PubMed1995

Reduced provirus burden and enhanced humoral immune function in AZT-treated SCID-feline mice inoculated with feline immunodeficiency virus.

The lack of a safe, economical murine lentivirus model for human immunodeficiency virus type 1 (HIV-1) infection of humans has hampered the preclinical evaluation of potential antiviral compounds, vaccines, and biological response modifiers. A small animal model that does not employ HIV-1 is needed to minimize risk of accidental human exposure, enhance efficient use of scarce experimental compounds, and reduce laboratory space necessary to conduct statistically significant in vivo trials. Feline immunodeficiency virus (FIV), an immunosuppressive lentivirus of domestic cats, has been used extensively as an animal model for the pathogenesis and therapy of human HIV-1 infection. Cats, however, are not amenable to large-scale efficacy trials because of their relatively large size, high cost, and limited degree of physiologic characterization, particularly with regard to drug metabolism. To adapt the feline immune system to a small laboratory animal host, severe combined immunodeficient mice (SCID mice) were engrafted with feline lymphoid tissues (forming the SCID-fe mouse) and inoculated with FIV. Two quantitative parameters, the incidence of provirus detection in feline tissue grafts and the level of feline IgG in plasma, were used to demonstrate the antiviral efficacy of 3'-azido-3'-deoxythymidine (AZT, azidothymidine, Retrovir, zidovudine) in the SCID-fe system. Of 17 SCID-fe mice inoculated with 7 x 10(6) peripheral blood mononuclear cells (PBMC) from an FIV-infected cat, eight had detectable FIV provirus in both the feline thymus and feline lymph node implants, as measured by polymerase chain reaction (PCR)/Southern blot analysis. Treatment of these mice with AZT at a dose of 125 mg kg-1 day-1 in drinking water beginning 1 day prior to FIV inoculation and continuing throughout the study interval prevented the dual detection of provirus in feline lymph node and thymus grafts of all mice tested. In a separate experiment, the level of spontaneous feline IgG production was quantified by ELISA 2 weeks after FIV inoculation with and without AZT treatment. Mean plasma feline IgG level of five SCID-fe mice inoculated with 10(3) TCID50 cell-free FIV was 2.23 mg ml-1. Mean feline IgG level of five mice inoculated with the same quantity of FIV and treated with AZT beginning 1 day prior to virus inoculation and continuing for 2 weeks thereafter was 14.98 mg ml-1. AZT significantly (P < 0.05) enhanced feline humoral immune function at a virus inoculum titer of 10(3) TCID50.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

PR8 influenza virus infection impairs serum thymic activity levels and thymus-derived immune functions in mice.

The levels of serum thymic activity (STA), the Thy-1.2 positivity of spleen "spontaneous" rosette-forming cells (SSRFCs) (measured in terms of Az sensitivity), as well as the blastogenic response to specific mitogens for T-lymphocytes, were studied in Balb/C mice after intranasal infection with A/PR/8/34 (HON1) influenza virus. As early as 12 hours, and more drastically, 24 hours the levels of STA were profoundly decreased after virus infection. Spleen Az sensitivity and blastogenic response of thymocytes and splenocytes to stimulation with Concanavalin A and Phytohemagglutinin, respectively, were depressed only later (day 2 or 3). These changes remain evident for about 1 week and later revert to normal values. All of the effects described are dose-dependent and appear to be virus related. Thence the PR8 virus infection initially induces a decrease of STA levels and secondly a impairment of thymus-derived immune functions.

Animals↗
PubMed1985

Immune function in chronic active Epstein-Barr virus infection.

The spectrum of illness attributed to Epstein-Barr virus (EBV) includes patients with symptoms persisting for more than 1 year without any other obvious underlying disease. High titers of antibodies to EBV, either IgG antiviral capsid antigen or anti-early antigen, can be demonstrated. In this study, 13 patients diagnosed as having chronic active EBV infection were examined to determine aspects of their immunologic status. Morphological examination and fluorescent antibody analysis revealed no abnormalities in the phenotypes of peripheral blood white cells present in these patients. Compared to those from healthy control individuals, mononuclear cells from the patients showed a markedly depressed ability to produce both interleukin-2 and interferon after stimulation with mitogen and a phorbol ester. Studies of natural killer (NK) cell activity revealed that unfractionated mononuclear cells from patients with chronic active EBV infection were significantly lower in killing activity compared to the control group. Fractionation procedures to enrich for large granular lymphocytes resulted in an increase in NK activity for all individuals, but killing activity still remained slightly lower in the patients than in the control group. The dysfunctions which were found in patients with chronic active EBV infection may reflect a primary defect in natural immune functions of the patients predisposing them to a chronic or intermittent clinical disease rather than a self-limiting illness. Alternatively, the abnormalities detected in these experiments may be a result of the viral infection itself.

Adolescent↗
PubMed2006

Evaluation of immunomodulation by Lactobacillus casei Shirota: immune function, autoimmunity and gene expression.

Lactic acid bacteria are claimed to have immunomodulating effects. Stimulation as well as suppression of T helper (Th)1 mediated immune responses, have been described for various strains. Experiments involving Lactobacillus casei Shirota (LcS) detected mainly enhancement of innate immune responses and promotion of Th1 mediated immune reactivity. To confirm and further investigate modulation of Th1 responses and development of autoimmune disease by LcS, the consequences of oral administration of LcS were assessed in several experiments. The effect of LcS varied between the different models. No modulation was found in the mitogen-induced cell proliferation and cytokine release assays in mesenteric lymph nodes of Wistar rats. LcS inhibited the Th1 mediated immune response in an adapted murine Local Lymph Node Assay (LLNA) in BALB/c mice, whereas experimental autoimmune encephalomyelitis (EAE) in Lewis rats was aggravated. These varying effects on Th1 responses indicate that beneficial as well as harmful effects on immune related disorders could occur after LcS consumption. Since microarray analysis is suggested to be more sensitive and predictive than functional tests, gene expression profiling was included as an alternative endpoint in the testing of immunomodulation. The detected gene expression profiles did not reflect the effects of LcS on the immune system. Microarray analysis may therefore have no more predictive value than immune function assays when investigating immunomodulation by probiotics. To gain further insight into effects of probiotics on immune function, experiments including cytokine assays and gene expression analysis combined with disease models could be useful.

Animals↗
PubMed2005

The immune function of MHC class II molecules mutated in the putative superdimer interface.

Analysis of the crystal structure of human class II (HLA-DR1) molecules suggests that the alphabeta heterodimer may be further ordered as a dimer of heterodimers (superdimer), leading to the hypothesis that T cell receptor dimerisation is a mechanism for initiating signaling events preceding T cell activation. The interface between pairs of molecules is stabilised by both salt bridges, polar and hydrophobic interactions. The residues that form the superdimer interface occur in three areas distinct from the antigen-binding groove. They can be defined as follows: region 1, beta-beta contacts in the helix of the beta1 domain; region 2, alpha-alpha contacts near the alpha 1/alpha2 domain junction and region 3; alpha-beta contacts in the alpha2/beta2 domains adjacent to the plasma membrane. To determine whether salt bridges and polar interactions formed within these regions are involved in the immune function of the murine MHC class II molecule, I-A(b), appropriate residues in both the alpha and beta chain were identified and mutated to uncharged alanine. Cell lines transfected with different combinations of mutated alpha and beta chains were generated and tested for MHC class II expression, peptide binding capabilities, and ability to present antigenic peptide to an OVA-specific T cell hybridoma. With the exception of two residues in region 2, the substitutions tested did not modulate MHC class II expression, or peptide binding function. When tested for ability to present peptide to an antigen-specific T cell hybridoma, with the exception of mutations in region 2, the substitutions did not appear to abrogate the ability of I-A(b) to stimulate the T cells. These results suggest that mutation of residues in region 2 of the putative superdimer interface have a gross effect on the ability of I-A(b) to be expressed on the cell surface. However, abrogation of salt bridges in region 1 and 3 do not influence I-A(b) cell surface expression, peptide binding or ability to stimulate antigen-specific T cells.

Animals↗
PubMed1990

[Effects of the polysaccharides isolated from mycelium and fermentation fluid of Schizophyllum commune on immune function in mice].

SPG1 and SPG2 are polysaccharides extracted respectively from fermented cultural mycelium and fermentation fluid of Schizophyllum commune. This paper reports the effect of SPG1 and SPG2 on concanavalin A (Con A) induced proliferation of lymphocyte from C57BL/6J mice in vitro. SPG1 (10, 25, 50 and 100 micrograms/ml) and SPG2 (10, 50 and 100 micrograms/ml) was found to significantly increase lymphocyte proliferation. In addition, SPG1 (10, 25, 50 and 75 micrograms/ml) antagonized the suppressive effect of hydrocortisone on proliferation of mouse spleen cells, while SPG2 did not. In vivo, at the dose of 2.5 and 5.0 mg/kg ip for 9 days, SPG1 and SPG2 remarkably enhanced the delayed-type hypersensitivity to 2, 4-dinitrochlorobenzene (DNCB) in mice. SPG1 (1.25, 2.5 and 5.0 mg/kg, ip for 1 day) and SPG2 (2.5 and 5.0 mg/kg, ip for 1 day) promoted the plaque forming cell (PFC) response to sheep red blood cells (SRBC) in mice. The effects of SPG1 and SPG2 on immune function were studied in aged immunodeficient mice. SPG1 (10 and 25 micrograms/ml) and SPG2 (25 micrograms/ml) was found to enhance the Con A induced lymphocyte proliferation in 14 months aged mice. At the dose of 2.5 mg/kg, SPG1 and SPG2 produced respectively 162.1 and 136.0% increase in PFC response in 14 months aged mice.

Animals↗
PubMed1998

Sodium butyrate upregulates Kupffer cell PGE2 production and modulates immune function.

The immunosuppressive effect of portal venous blood transfusions in organ transplantation has been well established and may be mediated by increased Kupffer cell production of the immunosuppressive arachidonic acid metabolite prostaglandin E2 (PGE2). In this study, butyrate, a short-chain fatty acid known to enhance gene transcription, is hypothesized to enhance Kupffer cell PGE2 production by altering cyclooxygenase or phospholipase A2 (PLA2) activity, thus augmenting the immunosuppressive effect of portal venous transfusion. Lewis rats were given a portal venous transfusion of Wistar-Firth blood or saline 1 h prior to Kupffer cell harvest. The in vitro effects of butyrate on Kupffer cell PGE2 production, cyclooxygenase, and PLA2 activity were assessed. Kupffer cell tumor necrosis factor-alpha (TNFalpha) production was also assessed due to its sensitivity to PGE2 and its proinflamatory effects. Kupffer cells from portally transfused animals produced significantly more PGE2 than saline-transfused controls. Addition of butyrate to the culture medium further increased PGE2 production by as much as sevenfold in Kupffer cells of portally transfused animals. Other short-chain fatty acids, propionate and hexanoate, did not increase PGE2 production. Butyrate added to Kupffer cells from transfused animals slightly upregulated inducible cyclooxygenase (COX-2) mRNA levels as measured by both Northern blot and reverse-transcriptase polymerase chain reaction and increased PLA2 activity fivefold as measured by Western blot. Kupffer cell immune function was also affected by in vitro butyrate treatment with a significant decrease in the production of TNFalpha. Thus, butyrate may be a useful immunoregulatory agent in organ transplantation protocols which seek to enhance transcription of immunosuppressive molecules.

Animals↗
PubMed1995

[Enhanced immune functions and antitumor activity of fibroblast-mediated interleukin-2 gene therapy].

The aim of the present study was to establish fibroblastmediated IL-2 gene therapy and to observe its antitumor effect in the mouse tumor model. The IL-2 gene-transfected fibroblasts (NIH3T3-IL-2+) secreting high level of IL-2 were encapsulated with collagen and then implanted i.p. into mice. Certain level of IL-2 could be detected in murine serum for some periods, and the splenic proliferation, NK and LAK activities, cytokine production (IFN-v, TNF, IL-2) were enhanced significantly. It was of great importance that the high endogenous LAK activity was induced. The significant therapeutic effect of i.p. implantation of NIH3T3-IL-2+ on ascitic liver carcinoma-bearing mice was observed. The better therapeutic results could be achieved. NIH3T3-IL-2+ cells were i.p. implanted in combination with i.p. injection of LAK cells. These results demonstrated that fibroblast--mediated IL-2 gene therapy has potent antitumor effect via augmentation of immune functions and the antitumor effect will be more obvious when IL-2 gene therapy is used along with the adoptive transfer of LAK cells.

3T3 Cells↗
PubMed1996

Immune functions in beluga whales (Delphinapterus leucas): evaluation of mitogen-induced blastic transformation of lymphocytes from peripheral blood, spleen and thymus.

A quantitative assay was developed to evaluate mitogen-induced lymphoblastic transformation in beluga whales (Delphinapterus leucas) using peripheral blood mononuclear cells, splenocytes and thymocytes. Optimal concentrations of four different mitogens (Con-A, PHA, LPS and PWM) were determined with the use of standard curves. Addition of human recombinant IL-2 (rhIL-2) after 48 h in culture with the different mitogens suggests that Con-A, PHA and PWM, but not LPS, stimulate T cells in belugas, as they do in other animal species. The addition of 2-mercaptoethanol did not enhance significantly the proliferation of cells stimulated by Con-A, PHA and LPS, while it did with the cells stimulated by PWM and those cultured without mitogen. The proliferative response of cells was suppressed when the culture medium was supplemented by beluga serum instead of fetal calf serum. This assay will be useful to assess the status of the immune functions in different populations of beluga whales as well for further in vitro immunotoxicological experiments.

Animals↗
PubMed1995

[Effects of Shenmai injection on immune function in stomach cancer patients after chemotherapy].

Sixty-three cases with stomach cancer were randomized and observed, the results showed that the count of T lymphocytes in chemotherapy combined with Shenmai injection (SMI) group increased, while in control group it decreased, the difference was significant (P < 0.05). The results also indicated that the count of OKT4 cells and the ratio of OKT4/OKT8 decreased after chemotherapy, but in SMI group both parameters increased in advence which were higher in the 4th week after chemotherapy than that before chemotherapy. However, the count of OKT1 cells and the ratio of OKT4/OKT8 were still in low level. Serum interleukin-2 receptor (sIL-2R) level also decreased (P < 0.05), while activities of natural killer cell (NK) and lymphokine activated killer cell (LAK) level increased (P < 0.05) in SMI group. Although the sIL-2R level had no change, both NK and LAK level decreased in control group. In addition, the difference of IgA, IgM, IgG level were not significant between these two groups. This suggested that SMI might improve human immune function to facilitate the chemotherapy of patients with stomach cancer.

Adenocarcinoma↗