Interaction of a lymphokine with normal human macrophages results in release of a suppressor factor for mitogen-induced immunoglobulin synthesis

Ingested (oral) SIRS peptide 1–21 inhibits acute EAE by inducing Th2-like cytokines

OBJECTIVE

Ingested type I IFN inhibits clinical attacks, relapses and inflammation in murine chronic relapsing EAE by inhibiting Th1-like cytokines. Type I IFN activates human suppressor T cells that produce SIRS.

METHODS

We examined whether oral (ingested) SIRS peptide inhibits EAE by decreasing Th1-like cytokines.

RESULTS

Parenteral SIRS peptide 1-21 showed a significant inhibition of disease severity in murine EAE. Ingested SIRS peptide at 10 and 100 microg SIRS peptide showed a significant inhibition of disease severity but also a prolonged delay in the onset of disease compared to placebo. There were significantly less inflammatory foci in the SIRS peptide fed group compared to the control mock fed group. Splenocytes from SIRS peptide 1-21 fed mice showed increased production of Th2-like CD30L, IL-13, TCA-3 cytokines/chemokines and decreased production of Th1-like cytokine lymphotactin.

INTERPRETATION

Ingested (oral) SIRS peptide significantly inhibits both clinical EAE and inflammation predominately via counter-regulatory type 2-like cytokines/chemokines IL-13, CD30L and TCA-3.

Effect of intravenous immunoglobulins on in vitro immunoglobulin formation in patients with antibody immunodeficiency

Seventeen patients with antibody immunodeficiency (9 subclass IgG immunodeficiencies, 8 common variable immunodeficiencies) and clinically unambiguous immunodeficiency symptomatology participated in the study with 14 healthy donors. The patients were given regular intravenous immunoglobulin (IVIG) infusions with Endobulin. Blood was collected before and 7 days after infusion of the usual IVIG dose. Mononuclear cells were isolated from peripheral blood (PBMC) of the patients by Ficoll-Paque gradient centrifugation. In order to monitor the ability to inhibit or activate polyclonal production of immunoglobulins in vitro, we stimulated PBMC with pokeweed mitogen (PWM) and with a mixture of pokeweed mitogen + concanavalin A (PWM+ConA). We found that an immunomodulatory effect of IVIG persists in vitro even one week after infusion. Polyclonally stimulated IgA and IgM production was suppressed by IVIG infusion mainly in patients with IgG subclass deficiency. The positive stimulatory effect of IVIG infusion on IgG production was confirmed. The IgG production increased in vitro after infusion in both groups of patients and was significantly higher than in healthy donors. Co-stimulation of PWM-stimulated cells with ConA caused an inhibition of immunoglobulin release in normal healthy donors. The infusion supported the capability of ConA to inhibit IgG production in vitro in patients with IgG subclass deficiency, whereas an increase in IgG production with PWM+ConA stimulation after infusion was found in CVID patients. We assume that lymphocytes activated by ConA produce suppressive factors, which can be affected by the IVIG infusion and which can have both an immunostimulatory and an immunosuppressive effect.

Human nonspecific suppressive lymphokines

Since the term "lymphokine" first appeared in print over 20 years ago, a tremendous number of these soluble mediators of the immune system have been described. Within the past few years, many human nonspecific suppressive lymphokines have been identified. This review discusses the historical basis of immunologic suppression and suppressor factors. Later reports describing suppressive human lymphokines are then grouped into four categories: primarily stimulatory lymphokines that also mediate certain suppressive activities, suppressive lymphokines produced during altered states of immunity, suppressive lymphokines produced by exogenously stimulated lymphocytes, and suppressive lymphokines produced by unstimulated lymphocytes. Recent work I have been involved in focusing on the human suppressive lymphokine soluble suppressor factor (SSF) is also discussed.