IFNy

In the 1980s, studies with EAE, an animal model mimicking MS, indicated that interferon y (IFN y) was effective in treating that disease and a trial was initiated to evaluate its potential benefit in human MS. Rather than showing efficacy, in 1987, use of IFNy as a therapy in MS patients caused an increase in clinical exacerbations and forced the clinical trial to terminate early (Panitch et al., 1987). Associated study of IFNy in 20 MS patients indicates increased concentrations of IFNy and TNFa precede the observation of clinical defects (Beck et al., 1988). An evaluation of primary RR-MS patient lymphocytes using flow cytometry supports a correlation between EDSS scores and IFNy secretion (Petereit et al, 2000). Intracellular cytokine immuno-staining of anti CD8-I- T cells reveals a correlation with IFNy and disease phase but not disease activity (Becher et al., 1999). What initially seemed efficacious in the EAE animal model, not only did not decrease MS symptoms but is now felt to be a marker of active inflammatory disease. 

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Stimulation of murine peritoneal macrophages with IFNy and LPS induced NO synthesis and activated IRE binding by IRP-1 and IRP-2. This activation is NO dependent and accompanied by a loss of the aconitase activity of IRP-1. This was also shown to occur in other cell types, such as the erythroid cell line K562, rat brain slices and mouse fibroblast lines and did not require cytokine stimulation. The activating effects of NO may depend on a direct interaction with the 4Fe-4S cluster or a slow effect on the low-molecular-weight iron pool. Activation of IRP-2 by LPS and IFN-y has not been universally confirmed (reviewed by Cairo and Pietrangelo, 2000). 

Fig. 11.2 Effect of HU on ET-1 release in the supernatant of the TrHBMEC (a) and EA hy 926 (b) cell cultures. Results of the quantitative assessment of ET-1 by Elisa, from at least four independent experiments in duplicates, are expressed in pg of ET-1 mb supernatant per 5x10s plated cells. Control basal culture conditions, HU cells treated with HU 250 mM during 48 h, Cyto cells treated with cytokines TNFa and IFNy at 100 U/mL 1 during 48 h, HU+cyto combination of HU and cytokines.

Fig. 11.4 Dose-response effect of HU on ET-1 peptide release (a) from TrHBM EC cells incubated with various concentrations of HU during 48 h in the presence (A) and absence ( ) of cytokines (TNFaand IFNy at 100 U mL 1). Under the same conditions, quantitative mRNA analysis was also performed and the residual percentage of expression, in the presence (b) and absence (c) of pro-inflammatory cytokines is given.

Fig. 11.7 Effect of HU on ml-CAM-1 expression in the TrHBMEC (a) and EA-hy 926 (b). These cells were incubated with HU 250 pM for 48 h with or without 100 U mb of TNFaand IFNy. mlCAM-1 cellular expression was analyzed by flow cytometry. Results are the Mean Fluorescent Index (MFI) of one representative experiment, with overall trend in three other independent experiments being comparable. Parallel estimation of slCAM-1 release in the culture supernatant of TrHBMEC cells (6 independent experiments) revealed that without cytokines sICAM-1 was not detectable in the supernatant for the basal conditions. The results of HU-treated cells (c) in the presence of cytokines showed a significant increase in release of slCAM-1 (p <0.05).

Details on the cellular immune responses occurring following the recognition of xenobiotic haptens as antigens by the immune system are described in chapters 33-35 of this volume. Ultimately, a certain combination of mediators is selectively activated and subsequently helps determine and differentiate the characteristic immune response (e.g., Thl vs. Th2). For example, dermal sensitizing chemicals (e.g., oxazolone and dinitrochlorobenzene) elicit a higher proportion of Thl cytokines such as IFNy and... 

CD8+CD69+ T cells was not observed in vivo. NK cells appeared to increase during the recovery period and an expansion of B cells was observed that persisted longer than that observed for T cells in individual animals. Transient, moderate elevations of serum IL-2, IL-5 (anti-inflammatory TH2-type cytokine), and IL-6 (inflammatory cytokine) was observed in individual animals at 2 or 24 hours following the initial dose but were not observed on Days 17 or 62 no changes in TNFa or IFNy (major pro-inflammatory cytokines) were observed. Thus, TGN1412 did not appear to be associated with a cytokine-release syndrome that has been observed in humans with upon administration of agonistic anti-CD3 antibodies.78... 

Compared to people in a noncontaminated area, plasma IgG levels were also significantly decreased in proportion to increasing plasma levels of TCDD in a cohort exposed in an industrial accident in Seveso, Italy.118 There was no effect on IgM or IgA levels, or on complement levels IgE was not measured. In separate studies, in vitro exposure to TCDD enhanced the spontaneous production of IgE by B cells isolated from atopic but not non-atopic individuals, but did not affect the levels of other isotypes.119 Other recent studies have reported small changes in immune cells from individuals exposed occupationally to PHAH.120121 For example, compared to unexposed controls, a cohort of men exposed occupationally to TCDD had diminished IFNy production in a recall response to tetanus toxin, while IFNy production following polyclonal activation was unaffected.120 This observation is consistent with mouse studies, in which antigen-specific responses are highly suppressed by TCDD, but mitogen-driven T cell responses are less susceptible to impairment.83 88122123... 

Immunocytokines Antibody or antibody fragment Cytokine, interleukin or growth factor aEpCAM-IL-12 aHer2/weM-IL-12 RM4-TNFa RM4-IFNy [119] [120] [121] [122]... 

Human IFNy Cytometric Bead Array (CBA) Flex set (Becton Dickinson, CA, USA). 

The presence of IFNy in cell culture supernatants from PBMCs stimulated with DIMS compounds was detected using CBA flex kit (Becton Dickinson) on a FACSArray flow cytometer (Becton Dickinson). The data were analyzed using FCAP Array software (Becton Dickinson). 

IFN production of PBMCs cultured in the presence of selected DIMS is shown from six healthy individuals (ELISA mean data of IFNa and IFNfl) and CBA mean data (IFNy) from four healthy individuals (Table 2). Different DIMS are capable of inducing IFN with different efficiency in human PBMCs (see Notes 1, 2, 5, 7, 8, 10-15 for comments on results). 

DIMS Primary structure 5-3 Major secondary structure Major tertiary structure (%) IFNa IFNp IFNy... 

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