PubMed HealthSearch

PubMed · 8397769

Immunostimulants.

Abstract

Nonspecific immunostimulation has progressed from crude microbially derived substances to chemically defined drugs with selective effects on different components of the immune system. John Hadden describes how immunopharmacological analyses of structure-activity relationships, pharmacokinetics and immunopharmacodynamics have directed the effective use of these agents in disease models and suggest that they may be of value in combination with other therapies in the treatment of immunodeficiencies, cancer, infections and even autoimmune disorders.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

J W Hadden. 1993. Immunostimulants.. https://doi.org/10.1016/0167-5699(93)90045-m

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

TGF-beta differentially modulates epidermal growth factor-mediated increases in leukemia-inhibitory factor, IL-6, IL-1 alpha, and IL-1 beta in human thymic epithelial cells.

The regulation of cytokine production by thymic epithelial cells (TEC) in the thymus is under coordinated and temporal control and is important for the development of T cells. Human TEC express TGF-beta R and epidermal growth factor (EGF) receptor, and produce TGF-beta 3 in vitro and in vivo. Furthermore, EGF has been shown to increase IL-1 alpha, IL-1 beta, IL-6 mRNA and protein levels in human TEC. Since EGF has been shown to modulate TGF-beta effector functions, we determined whether TGF-beta can modulate EGF-mediated increases in cytokine gene expression in human TEC. We established that a single TEC expresses both EGF receptor and TGF-beta R. TGF-beta plus EGF synergistically increased leukemia-inhibitory factor (LIF), additively increased IL-6, but had little effect on IL-1 alpha and IL-1 beta mRNA levels. In contrast, TGF-beta alone increased LIF and IL-6, had little effect on IL-1 alpha, and slightly decreased IL-1 beta mRNA levels. The increases in LIF and IL-6 mRNA levels by TGF-beta plus EGF correlate with the increases in LIF and IL-6 concentrations in TEC culture supernatants as detected by ELISA. We also determined the mechanism responsible for the increases in cytokine mRNA levels. TGF-beta plus EGF did not affect transcription of LIF and IL-6 genes; this suggests that the increases in the steady state levels of cytokine mRNA were mediated post-transcriptionally, most likely at the level of mRNA stability. Our data demonstrate that TGF-beta modulates TEC cytokine production. We speculate that TGF-beta produced in situ plays a role in thymocyte development by directly affecting thymocyte differentiation and by indirectly modulating TEC cytokine production.

Adjuvants, Immunologic

Granulocyte-macrophage colony-stimulating factor and IFN-gamma restore the systemic TNF-alpha response to endotoxin in lipopolysaccharide-desensitized mice.

The influence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and IFN-gamma on the restoration of impaired TNF-alpha release in LPS-desensitized mice or their refractory macrophages was investigated. Mice pretreated with GM-CSF or IFN-gamma (50 microg/kg i.v.) and injected with 3 mg/kg LPS i.p. displayed increased plasma TNF-alpha levels compared with LPS controls. IL-10 was marginally up-regulated by GM-CSF but abrogated by IFN-gamma pretreatment. LPS-tolerant mice (30 microg/kg LPS i.p., -24 h) showed an attenuated plasma TNF-alpha and IL-10 response to LPS and survived LPS shock. Pretreatment of such mice with GM-CSF or IFN-gamma restored the previously impaired TNF-alpha response. In cultures of murine monocyte/macrophage-containing cell populations, i.e., alveolar, peritoneal, spleen, bone marrow cells, or blood, the presence of GM-CSF or IFN-gamma (10 ng/ml) resulted in an enhanced release of TNF-alpha initiated by 1 microg/ml LPS. Cells from LPS-tolerant mice showed a diminished responsiveness to LPS. However, when exposed to GM-CSF or IFN-gamma ex vivo, their TNF-alpha response to LPS was partially restored. These findings characterize GM-CSF and IFN-gamma as potent enhancers of LPS-induced TNF-alpha production in normal as well as in experimentally immunocompromised mice and provide the rationale for further experiments to explore the pharmacologic use of these cytokines for restoration of immunocompetence in sepsis-associated immunosuppression.

Adjuvants, Immunologic

IL-13 protects mice from lipopolysaccharide-induced lethal endotoxemia: correlation with down-modulation of TNF-alpha, IFN-gamma, and IL-12 production.

IL-13 is a potent down-modulator of macrophage proinflammatory activity in vitro, similar in this context to the anti-inflammatory cytokines IL-4 and IL-10. Since IL-10 effectively confers protection to mice from LPS-induced lethal endotoxemia through inhibition of proinflammatory cytokine production, we investigated whether IL-13 may also be capable of providing protection in this experimental model of endotoxic shock. A single injection of recombinant murine IL-13 (rmIL-13; 0.5-10 microg) significantly increased survival in a dose-dependent manner when a lethal i.p. injection of endotoxin was administered to BALB/c mice. This effect appeared to be IL-13 specific, since survival was not affected in mice that received heat-inactivated rmIL-13. rmIL-13 provided significant protection to mice even when given 30 min after LPS injection; however, this protection decreased in a time-dependent manner as the administration of rmIL-13 was delayed by 1, 2, and 5 h following LPS injection. The protective effect of IL-13 was correlated with significant decreases in the production of the inflammatory mediators TNF-alpha, IFN-gamma, and IL-12 as well as a decrease in the anti-inflammatory mediator IL-10. Our data suggest that IL-13 provides protection from LPS-induced lethal endotoxemia in a manner that is similar to but independent from that of IL-10, and therefore can be added to the list of cytokine immunomodulators that might be beneficial in the treatment of septic shock.

Adjuvants, Immunologic