Molecular Analysis of Decreased Interleukin-12 Production in Persons Infected with Human Immunodeficiency Virus

Abstract

Human immunodeficiency virus (HIV) disease is associated with loss of type 1 responses, including interleukin (IL)-12 production. The dramatic drop in p70 production seen at early stages of disease was found not to be associated with a similarly decreased p40 mRNA expression. p35 mRNA expression was more extensively reduced than p40 mRNA expression at these early stages. Monocytes infected in vitro with HIV displayed decreased p35 expression and p70 production, suggesting that such decreased IL-12 expression may contribute to reduced IL-12 production in HIV-positive patients' cells. In addition, treatment of cells with IL-10 increased IL-10 mRNA expression and decreased p40 expression in both HIV-positive and -negative cells, while neutralization of IL-10 increased p40 mRNA levels. These observations, together with the observed hyperproduction of IL-10 in HIV-positive patients, may explain the dysregulation of IL-12 production seen in HIV disease.

CD40 Ligand Dysregulation in HIV Infection: HIV Glycoprotein 120 Inhibits Signaling Cascades Upstream of CD40 Ligand Transcription

“…Among the APC functions that have been reported defective in HIV infection is a marked impairment of production of IL-12 by PBMC and macrophages from HIV-infected (HIV ϩ ) patients (1)(2)(3)(4)(5)(6)(7)(8)(9). This defect in IL-12 production does not reflect a global deficiency in secretion of proinflammatory cytokines by APC, as production of TNF-␣ and IL-1␤ are not reduced (1,2).…”

“…This defect in IL-12 production does not reflect a global deficiency in secretion of proinflammatory cytokines by APC, as production of TNF-␣ and IL-1␤ are not reduced (1,2). IL-12 is a key link between innate and adaptive immunity (reviewed in Ref.…”

“…Total RNA was extracted using RNAeasy mini kits, following manufacturer's instruction (Qiagen). RNA was quantified by spectrophotometer absorbance and 0.5 g of RNA was reverse-transcribed using superscript reverse transcriptase (Life Technologies) and random primers (Roche Molecular Systems, Pleasanton, CA), as described earlier (2). A one-fourth dilution of the RT product was amplified using real-time PCR, performed in a Light-Cycler (Roche) using a SYBR green PCR kit (Roche) and specific primers to amplify 100-200 bp fragments from the different genes analyzed.…”

Transcriptional Inhibition of Interleukin-12 Promoter Activity in Leishmania Spp.–Infected Macrophages

“…killing is indeed delayed (Melby, 1991). Inhibition of MP IL-12 production and resulting Th1 responses is not unique to Leishmania; viruses (Chehimi et al, 1994;Chougnet et al, 1996;Karp et 1996) and bacteria (Marth and Kelsall, 1997;Sutterwala et al, 1997;Matsunaga et al, 2003) also exploit this mechanism to avoid clearance.…”

“…killing is indeed delayed (Melby, 1991). Inhibition of MP IL-12 production and resulting Th1 responses is not unique to Leishmania; viruses (Chehimi et al, 1994;Chougnet et al, 1996;Karp et 1996) and bacteria (Marth and Kelsall, 1997;Sutterwala et al, 1997;Matsunaga et al, 2003) also exploit this mechanism to avoid clearance.The general nature of impaired IL-12 production in Leishmania spp.-infected MP has extended to every IL-12 agonist that has been tested. Leishmania spp.-infected MP are unable to produce IL-12 even in response to strong inflammatory stimuli, including microbial stimuli, e.g., lipopolysaccharide (LPS), Staphylococcus aureus (SAC), Toxoplasma gondii antigen, and mycobacteria (Carrera et al, 1996;Sartori et al, 1997;Belkaid et al, 1998;Weinheber et al, 1998;Piedrafita et al, 1999), and T-cell-dependent agonists, e.g., IFN-γ and CD40L (Carrera et al, 1996;Belkaid et al, 1998;Weinheber et al, 1998;Piedrafita et al, 1999).…”