Distribution and kinetics of superantigen-induced cytokine gene expression in mouse spleen.

Abstract

SummaryThe polyclonal stimulation of T cells by bacterial superantigens is involved in the pathogenesis of the toxic shock syndrome in certain staphylococcal and streptococcal infections. Here we describe the onset and kinetics of superantigen-induced cytokine production in situ in spleens of normal BALB/c mice monitored at the level of cytokine mRNA expression by in situ hybridization. Messenger RNAs for interleukin 2 (IL-2), interferon % and tumor necrosis factors (TNF) c~ and/3 were not expressed at detectable levels in spleens of unstimulated animals but became visible already 30 min after intraperitoneal application of 50/~g staphylococcal enterotoxin B. All mRNA levels showed peak expression approximately 3 h after injection and a slow decrease up to 24 h after injection. Expression of the mRNAs was restricted to the T cell-dependent area of the periarteriolar lymphatic sheets of the spleen. Interestingly, TNF-oe mRNA showed a biphasic response, the early appearing mRNA had the same localization as the other mRNAs, whereas after 3 h TNF-ol mRNA showed a broader distribution indicating a second cell population producing TNF-o~. The expression of IL-2 and TNF proteins in the serum increased in parallel to the observed mRNA changes with a slight delay. The presence of macrophages was not required for the expression of the cytokine mRNAs in the spleen as the expression was unchanged in macropbage-depleted mice. Only the second phase of TNF-c~ mRNA expression was abrogated in such animals. The expression of all mRNAs was completely suppressed by prior administration of cyclosporin A. These data show that nonphagocytic cells are the essential superantigen-presenting cells in vivo and indicate that at least part of the pathogenetic TNF-ol is T cell derived. n in situ analysis of a T cell response should provide information on the distribution of induced events in the affected organs and on the kinetics of the response. In contrast, in vitro experiments allow only a vague approximation of the kinetics of an immune response and do not give much information on the significance of cellular interactions for the events in vivo. It is therefore surprising that such analyses in vivo have only rarely been performed so far, possibly because of the usually low frequency of responding cells in antigen-specific immune reactions.The study of a superantigen response has the advantage that a superantigen activates a large fraction of T cells by a mechanism closely resembling antigen recognition. Superantigens, such as the staphylococcal enterotoxins, cross-link variable parts of the TCR with MHC class II antigens on APCs. Consequences of this massive T cell activation are the transient expansion of the stimulated T cell subset followed by death and development of anergy in these cells, and eventually shocklike symptoms due to a burstlike expression of different cytokines (1, 2).TNF has been reported to play a critical role in the development of superantigen-induced toxic shock because an antibody against TNF has a protective eff...

Relationship of varying patterns of cytokine production to the anorexic and neuroendocrine effects of repeated Staphylococcal enterotoxin A exposure☆

“…A major property of SEA is the ability to stimulate T cells bearing the Vβ3 and Vβ11 T cell receptor phenotypes, resulting in pronounced cytokine production and T cell proliferation. Similar effects on cytokine production are observed with other staphylococcal enteroxins, such as staphylococcal enterotoxin B (SEB) (Bette et al, 1993). Indeed, rodents challenged with SEA or SEB produce high levels of interleukin-2 (IL-2) and tumor necrosis factor α (TNFα), and these changes are associated with activation of the hypothalamic-pituitary-adrenal (HPA) axis (Bette et al, 1993;Goehler et al, 2001;Gonzalo et al, 1993;Kusnecov and Goldfarb, 2005;Sundstedt et al, 1994).…”

Trypanosoma cruzi induces strong IL-12 and IL-18 gene expression in vivo: correlation with interferon-gamma (IFN-γ) production

“…In situ hybridization using 35 S-labelled in vitro transcribed cRNA probes on cryostat section was performed as described previously [28,29]. After 15 days at 4ЊC sections were developed in Kodak D-19 developer and counterstained with haemalaun.…”

“…35 S-labelled RNA probes and in situ hybridization The IFN-g and the IL-12 p40 probes have been described [28,29]. IGIF- [21] and T. cruzi- [30] specific probes were cloned in the Bluescript KS vector (Stratagene, Heidelberg, Germany).…”

“…Subcloning of specific DNA fragments in plasmids with SP6 or T3/T7 initiation sites (Boehringer, Mannheim, Germany) was done by standard protocols. In vitro transcription of sense and antisense probes was performed as described [28,29].…”

Effect of Treatments with Cyclosporin A and Anti‐Interferon‐γ Antibodies on the Mechanisms of Immune Tolerance in Staphylococcal Enterotoxin B Primed Mice

“…Because SEB immunization also allows us to follow in vivo the responses of these reactive T cells, it has been widely used as an important experimental model for studying peripheral T cell activation and tolerance induction [2][3][4][5][6]. Following SEB injection in mice, a strong immune response occurs within the first 24 h (early phase) resulting in the release of large amounts of cytokines [7][8][9], and disappearance of Vb8 þ T cells due to deletion through apoptosis [3,4,6]. Thereafter on days 2-4, Vb8 þ T cells proliferate, achieving high percentages in the spleen as well as in the blood [10].…”