Decoy receptors: a strategy to regulate inflammatory cytokines and chemokines

Cytokines, acute-phase proteins, and hormones: IL-1 and TNF-alpha production in contact-mediated activation of monocytes by T lymphocytes

The cytokine network is a homeostatic system that has to be perceived in an analogous fashion to the acid/base equilibrium. The level of any cytokine in biological fluids can be interpreted correctly only by taking into account the levels of other synergistic cytokines, of their respective inhibitors, and of each cytokine receptor. Due to their potent activities in many different processes (including cell growth and differentiation, development, and repair processes leading to the restoration of homeostasis), the cytokine activities have to be tightly controlled by natural inhibitory mechanisms. Since one of the main functions of cytokines is to mediate interactions between the immune and inflammatory system, it is thought that chronic immuno-inflammatory diseases might be caused in part by the uncontrolled production of cytokines. Depending on the stage of inflammation or the biological effect determined, the same cytokine might be pro- or anti-inflammatory. This applies, for instance, to IL-4, IL-10, and TGFbeta. An important mechanism that triggers the production of pro-inflammatory cytokines in chronic inflammatory diseases is the direct cellular contact between stimulated T cells and monocyte-macrophages. This mechanism is blocked at the systemic level by the "negative" acute-phase protein apolipoprotein A-I (apo A-I). The levels of expression of cytokines and cytokine inhibitors and acute-phase proteins are ruled by hormones. Estrogens as well as androgens inhibit the production of IL-1beta and TNF-alpha on monocyte-macrophages. However, androgens antagonize estrogen stimulatory effects on apo A-I synthesis by the liver. Other studies suggest that estradiol is more inhibitory to Thl cytokines (e.g., IFNgamma, IL-2), while testosterone is inhibitory to Th2 cytokines (e.g., IL-4). Cytokines also control the axis of the hypothalamic-hypophyseal-adrenal glands as well as the sexual hormones. The discrepancy between studies would suggest that the mechanisms are different in physiological and pathophysiological conditions.

Molecular mechanisms of neutrophil recruitment elicited by bacteria in the lungs

The recruitment of leukocytes to an extravascular destination requires intercellular communication between tissue cells and leukocytes. The molecules mediating this intercellular communication play differing roles in recruiting different types of leukocytes, in response to different stimuli, in different tissues, and in different hosts. The present communication reviews the adhesion molecules, chemokines, other cytokines, and NF- kappa B proteins which regulate the recruitment of neutrophils elicited by bacteria in the lungs.

The Cytokine Odyssey 2001, a joint meeting of the Society of Leukocyte Biology and the International Cytokine Society. 8-11 November 2001, Maui, Hawaii, USA

The Cytokine Odyssey 2001 was held at the Outrigger Wailea Resort in Maui, Hawaii, USA. The meeting, jointly sponsored by the International Cytokine Society (ICS, 9th Annual Meeting) and the Society of Leukocyte Biology (SLB, 35th Annual Meeting), was organised by Carl Ware (Chair) from the La Jolla Institute for Allergy and Immunology (La Jolla, USA) and Thomas Hamilton (Co-Chair) from the Cleveland Clinic Foundation (Cleveland, USA). This international conference was designed to bring together leading investigators in molecular and cellular biology, physiology and genetics, interested in cytokines and cells of the immune system. This forum was aimed to assess the impact of this expanding science on new approaches to disease intervention [1].