Endogenous interleukin-4, but not interleukin-10, is involved in suppression of host resistance against Listeria monocytogenes infection in interferon-depleted mice

Abstract

The production and roles of endogenous interleukin-4 (IL-4) and IL-10 in a sublethal infection with Listeria monocytogenes were studied in normal mice and anti-gamma interferon (IFN-␥) monoclonal antibody (MAb)pretreated mice. In normal mice, the expression of mRNAs for IL-4 and IL-10, which was amplified by reverse transcription-PCR, was induced in the spleens and livers either early or late in infection, although the serum IL-4 and IL-10 were not detectable by enzyme-linked immunosorbent assays. In vivo administration of anti-IL-4 MAb showed no effect on antilisterial resistance, whereas anti-IL-10 MAb partially diminished the defense. In anti-IFN-␥ MAb-pretreated mice, a delay in the bacterial elimination from the spleens and livers was observed and high titers of serum IL-4 and IL-10 were induced late in infection. Production of endogenous IL-4 and IL-10 was suppressed in both CD4 ؉ cell-and CD8 ؉ cell-depleted mice. The suppression of antilisterial resistance in anti-IFN-␥ MAb-pretreated mice was canceled when anti-IL-4 MAb was injected late in infection, whereas anti-IL-10 MAb showed no effect. These results suggest that the host immune responses were polarized into the T-helper 2 phenotype in anti-IFN-␥ MAb-pretreated mice and that inhibition of host resistance against L. monocytogenes by depletion of IFN-␥ might be attributable to IL-4 produced by T cells polarized into the T-helper 2 phenotype as well as the inhibition of the IFN-␥ effects.

Roles of endogenous cytokines in liver apoptosis of mice in lethal Listeria monocytogenes infection

“…L. monocytogenes 1b-1684 cells [24] were grown in tryptic soy broth (Difco Laboratories, Detroit, MI, USA) at 37³C for 16 h. Mice were infected i.v. with 0.2 ml of a solution containing 5U10 6 colony-forming units (cfu) of viable L. monocytogenes 1684 cells in 0.01 M phosphate-bu¡ered saline (PBS ; pH 7.4).…”

“…Normal rat globulin (NRG) was injected as a control for the mAbs. NRG was prepared as described previously [24].…”

Effect of a matrix metalloproteinase inhibitor on host resistance against Listeria monocytogenes infection

“…L. monocytogenes 1b-1684 cells were prepared as described previously [27]. Mice were infected intravenously with 0.2 ml of a solution containing various numbers of viable L. monocytogenes in 0.01 M phosphate-bu¡ered saline (PBS, pH 7.4).…”

“…Hybridoma cell lines secreting monoclonal antibodies (mAbs) against mouse TNF-K (MP6-XT22.11; rat IgG1) and against mouse CD95L (MFL-1; hamster IgG) [28] were injected into pristane-primed CD-1 nu/nu mice. The mAbs found in the ascites £uid were partially puri¢ed by (NH 4 ) 2 SO 4 precipitation [27]. The mice were given a single intravenous injection of 50 Wg of anti-TNF-K mAb or 1 mg of anti-CD95L mAb 1 h before infection.…”

“…After 48 h of incubation at 37³C in a humidi¢ed 5% CO 2 incubator, the supernatants were collected. For estimation of endogenous cytokine production, the livers and spleens from infected mice were suspended in RPMI 1640 medium containing 1% (w/v) CHAPS (Wako Pure Chemical Co., Osaka, Japan) and 10% (w/v) homogenates were prepared with a Dounce grinder and then clari¢ed by centrifugation at 2000Ug for 20 min [27]. The culture supernatants, organ extracts, and sera were stored at 380³C until cytokine assays were performed.…”