Decreased interleukin-12 (IL-12) from activated cord versus adult peripheral blood mononuclear cells and upregulation of interferon-γ, natural killer, and lymphokine-activated killer activity by IL-12 in cord blood mononuclear cells

Sun Min Lee, Yu Suen, Leh Chang, Vivian Bruner, John Qian, Jeff Indes, Eva Knoppel, Carmella Van De Ven, Mitchell S. Cairo

Research output: Contribution to journalArticlepeer-review

155 Scopus citations

Abstract

Interleukin-12 (IL-12) is a critical cytokine regulating natural killer (NK) and T-cell function. We hypothesized that the impaired ability of cord blood (CB) to produce normal adult levels of IL-12 in response to stimulation may contribute to the immaturity of CB immunity. Furthermore, exogenous IL-12 may compensate for the immaturity in CB cellular immunity and have the potential for immunotherapy post cord blood transplantation. We compared the expression and production of IL-12 from activated cord versus adult mononuclear cells (MNC), regulatory mechanisms associated with IL-12 expression in CB MNC, and the effects of IL-12 on induction of CB interferon (IFN)-γ, production, NK, and lymphokine-activated killer (LAK) cytotoxicity. Northern analysis and enzyme-linked immunosorbent assay were performed in lipopolysaccharide (LPS)- stimulated CB and adult peripheral blood (APB) MNC. IL-12 mRNA expression was induced within 6 hours with LPS (10/μg/mL) and reached peak levels at 12 hours in both CB and APB MNC. However, IL-12 mRNA expression and protein accumulation in CB MNC were 35.8% ± 4.84% (12 hours, n = 11, P < .05), and 17.6% ± 1.7% (24, 72, 96 hours, n = 9, P < .05) respectively, when compared with APB MNC. Nuclear run-on assays showed no differences between CB and APB MNC in both the basal levels of transcription and the degree of transcriptional activation. However, the half-life of IL-12 p40 mRNA was approximately threefold lower in activated CB MNC than in activated APB MNC (CB: 114 ± 3.0 minutes v APB: 353 ± 7.8 minutes, n = 3, P < .05). Exogenous IL-12 {10 U/mL) induced a significant increase of IFN-γ, from both CB and APB MNC (24 hours, 72 hours, P < .05, n = 3). The stimulated CB IFN-γ level reached comparable levels produced by unstimulated APB. IL-12 treatment also significantly enhanced CB NK cytotoxicity against K562 and NB-100 cell lines to the comparable levels of APB (P < .05, n = 4). CB MNC was more responsive to IL-12 stimulation with respect to IFN-γ production, NK, and LAK cytotoxicity when compared with APB. The present study suggests that IL-12 mRNA and protein expression is decreased in activated CB. This discrepancy in IL-12 production is secondary, at least in part, to the altered posttranscriptional regulation. The impaired ability of CB MNC to produce IL-12 in response to stimulation may contribute to the decrease in IFN-γ production and NK cytotoxicity. However, IL-12 enhanced IFN- γ and NK activity in CB MNC up to the comparable levels of APB MNC. These findings suggest that reduced expression and production of IL-12 from activated CB may contribute to the immaturity in CB cellular immunity and contribute, in part, to decreased graft-versus-host disease following CB stem cell transplantation.

Original languageEnglish (US)
Pages (from-to)945-954
Number of pages10
JournalBlood
Volume88
Issue number3
DOIs
StatePublished - Aug 1 1996
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

Fingerprint

Dive into the research topics of 'Decreased interleukin-12 (IL-12) from activated cord versus adult peripheral blood mononuclear cells and upregulation of interferon-γ, natural killer, and lymphokine-activated killer activity by IL-12 in cord blood mononuclear cells'. Together they form a unique fingerprint.

Cite this