Modulation of cytokine mRNA expression by brain-derived neurotrophic factor and nerve growth factor in human immune cells.

Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) exert various effects on immune cells. Here we studied, whether they influence the cytokine expression pattern in peripheral blood mononuclear cells (PBMCs) or antigen specific T-cells. In PBMCs BDNF and NGF had interindividually variable effects on T helper cell type (Th)1- and Th2-cytokines. However, there was a high correlation between the modulating properties of these neurotrophins (r=0.97) concerning the expression of interleukin (IL) 4, transforming growth factor-beta and tumour necrosis factor-alpha mRNA at a concentration of 100 ng/ml. In myelin basic protein-specific T-cell lines BDNF and NGF increased interferon -gamma mRNA to a moderate extent, but not IL4. No major effects were detected at the cytokine protein level. In conclusion, our results suggest a partial effect of neurotrophins on immune cells, which may be modified by other signals.

Influenza vaccination in MS: absence of T-cell response against white matter proteins.

BACKGROUND: Natural infections bear the risk of triggering MS bouts, whereas epidemiologic studies have not delineated an increased risk for disease activity after influenza virus vaccination. OBJECTIVE: To examine influenza A virus-specific and myelin protein-reactive T-cell frequencies by interferon gamma (IFNgamma)-enzyme-linked immunospot and the response of these cells by IFNgamma-reverse transcription (RT) PCR after immunization and any incidental upper respiratory tract infection (URI) in 12 patients with MS (seven with a relapsing-remitting course; five with a secondary progressive course; Kurtzke Expanded Disability Status Scale [EDSS] score from 1.0 to 6.5, without immunosuppressive treatment) and 28 healthy volunteers. RESULTS: A cellular immune response against influenza A virus was mounted in both populations at 2 weeks after vaccination. Patients with MS showed a higher relative increase (p = 0.008) than controls with respect to the number of influenza-specific T cells. Mean antibody responses against influenza A virus were increased in both populations after 2 weeks (p < 0.01). Despite these virus-specific reactions, no increase in T-cell frequencies responsive to human myelin basic protein (MBP) or recombinant human myelin oligodendrocyte protein (MOG) was observed after immunization, arguing against a general immune stimulation by influenza vaccination. In contrast, MBP-specific T-cell responses became detectable in several individuals after febrile infection. CONCLUSION: These data support the clinical observations that influenza vaccination is effective and safe in patients with MS with respect to cellular immunoreactivity against two main CNS myelin proteins.

Characterization of early immunological responses in primary cultures of differentially activated human peripheral mononuclear cells.

Specific immune cell activation is a hallmark of infections and autoimmune disorders. Quantification of proliferative cell responses by (3)H-thymidine incorporation is a slow process and describes only one type of cellular reaction. We here investigated early immunological responses of purified human peripheral blood mononuclear cells to the direct stimulus alpha CD3 and antigen specific stimulation (human myelin basic protein (hMBP), tetanus toxoid, and influenza vaccine) and compared them to polyclonal LPS stimulation. Cytokine mRNA levels were quantified using real-time quantitative reverse transcriptase polymerase chain reaction (RT PCR) 4 h, 16 h, and 48 h after activation. Proliferation was measured 96 h after initiation of the cultures. Antigen specific responses were detected as early as 4 h after stimulation and followed different kinetics depending on the mode of activation. We demonstrated significant correlations of cytokine mRNA and protein expression for TNF alpha, IL10, and IFN gamma. Expression of IL2 mRNA at 16 h was correlated with proliferation indices at 96 h whereas IL4 mRNA levels were negatively correlated. Early cytokine mRNA expression in stimulated immune cells provides important functional data and is a powerful tool with which to study immunological reactions.

Variations in cytokine mRNA expression during normal human pregnancy.

Epidemiological data provide evidence that disease activity of T cell-mediated, organ-specific autoimmune diseases is reduced during pregnancy. Although there are several experimental animal studies on the effect of pregnancy on the immune system, the situation in humans is less clear. We therefore performed a prospective analysis of cytokine mRNA expression in whole blood by a new on-line reverse transcriptase-polymerase chain reaction technique and of serum hormone levels during pregnancy in healthy women. The control group included age-matched non-pregnant healthy women. Quantitativecytokine mRNA expression revealed significantly reduced IL-18, interferon-gamma (IFN-gamma), and IL-2 mRNA levels in the first and second trimester in pregnancy compared with non-pregnant women. No difference between groups was detected for tumour necrosis factor-alpha (TNF-alpha) mRNA. IL-4 and IL-10 mRNA were detected at low levels in only 20% of pregnant women and were reduced to a statistically significant extent in the second and third trimester compared with the control group. Changes in IL-18 mRNA expression correlated inversely with serum values for human choriogonadotropin (HCG) and IL-10 serum levels correlated with increases in serum 17beta-oestradiol levels. These data indicate immunomodulatory effects of pregnancy at the cytokine level which may be related to the variations in the clinical course of organ-specific, T cell-mediated autoimmune diseases during pregnancy.