Plasmacytoid dendritic cell interferon-α production to R-848 stimulation is decreased in male infants
© Wang et al.; licensee BioMed Central Ltd. 2012
Received: 12 April 2012
Accepted: 6 July 2012
Published: 6 July 2012
Sex differences in response to microbial infections, especially viral ones, may be associated with Toll-like receptor (TLR)-mediated responses by plasmacytoid dendritic cells (pDCs).
In this study, we identified sex differences in human infant pDC interferon-α production following challenge with the TLR7/8 agonist R-848. Male pDC responses were significantly lower than those of females during early infancy. This difference may be attributed to the androgen surge experienced by males during the early infancy period. Pretreatment of human pDCs with dihydrotestosterone produced a significant reduction in interferon-α production following R-848 challenge.
Androgen-mediated regulation of pDC TLR7-driven innate immune responses may contribute to the observed sex differences in response to infections during early infancy.
KeywordspDC IFN-α TNF-α Infant TLR7
Plasmacytoid DCs (pDCs) are highly specialized cells that produce large amounts of interferon-α (IFN-α) in response to a wide range of viruses and other microbial stimuli [1, 2]. Infant and adult human pDCs express high levels of Toll-like receptors (TLRs) 7 and 9, but not TLR8 [3, 4]. Human TLRs 7 and 8 are members of the endosomal TLR9 subfamily that sense RNA moieties intracellularly and signal through the adaptor MyD88 . The imidazoquinolone and guanosine-like compound, resiquimod (R-848), stimulates human TLRs 7/8 [6, 7].
Sex differences in adult pDC IFN-α production have been previously described, with production being higher in females than males [8, 9]. However, the reported effects of female sex hormones on TLR7-mediated pDC IFN-α production have been varied [8–10]. The effects of male sex hormones have not been previously determined. Within the first six months of life, infants experience a “mini-puberty”. During this time period, circulating levels of sex hormones approach the levels seen during puberty . We found that during the “mini-puberty” period female infant pDCs also have higher pDC IFN-α production than male infants in response to 1 μM R-848 stimulation. Androgen signaling downregulated R-848 stimulated pDC IFN-α production. This sex effect on pDC IFN-α production may play a role in the female survival benefit seen during early infancy. However, the effect of sex on pDCs may have a cost of higher rates of systemic lupus erythematosus (SLE) and autoimmune diseases later in adult females compared to adult males [12, 13]. Here we describe a novel effect of male sex hormones on TLR7-mediated pDC IFN-α production.
Results and discussion
Female infants enjoy a survival benefit compared to male infants in the first six months of life. In particular, Staphylococcus aureus infections  and respiratory viral infections such as respiratory syncytial virus (RSV)  predominate in males during early infancy. Staphylococcus aureus and several airborne and respiratory RNA viruses (including RSV) can modulate TLR7-mediated pDC IFN-α production during their pathogenesis [22–24]. Higher pDC IFN-α production in females during early infancy may contribute to their survival benefit. Later in life, this sex effect may contribute to a higher incidence of SLE and autoimmune diseases in females [12, 13].
We found that R-848-stimulated pDC IFN-α production, but not pDC TNF-α production, was higher in girls compared to boys during early infancy. Androgen signaling downregulated R-848-stimulated pDC IFN-α production, but not pDC TNF-α production, in a dose dependent fashion. We postulate that androgen effects on pDCs play a role during the “mini-puberty” of early infancy in the sex differences of R-848-stimulated pDC IFN-α production.
Infant clinical study
The infant clinical study was approved by the institutional review boards of the Research Institute for Tropical Medicine, Philippines, and the University of Massachusetts Medical School (UMMS). Mothers and their healthy infants were recruited and enrolled after providing written informed consent. Study enrollment began in October 2006 in San Pablo, Philippines. Blood samples were collected from healthy infants and their mothers when the infant was between 6–18 weeks old. Normalized child growth indicators were determined using WHO child growth standards . PBMC were isolated by Ficoll-Hypaque density centrifugation from infant blood samples and cryopreserved.
Antibodies and fluorophores
The following monoclonal antibodies (mAbs) and fluorophores were used: mouse mAb anti-human CD123 eFluor NC650 (eBioscience, San Diego, CA), anti-human CD303 APC (Miltenyi Biotec, Auburn, CA), anti-human tumor necrosis factor-α (TNF-α) PerCPCy5.5 (Biolegend, San Diego, CA), and anti-human IFN-α FITC (PBL Interferon Source, Piscataway, NJ).
Intracellular cytokine staining (ICS)
PBMC were resuspended in RPMI 1640 (Invitrogen Life Technologies, Grand Island, NY), 10 % FCS (HyClone, Logan, UT), 10 ng/ml rIL-3 (R&D Systems, Minneapolis, MN), and 20 μg/ml DNase (Sigma-Aldrich, St. Louis, MO). 1.5 × 106 PBMC were placed in polypropylene tubes with 1 μM R-848 (Invivogen, San Diego, CA 0.5 μg/ml brefeldin A (BD Pharmingen, San Diego, CA), and incubated for 16 h in a 37 °C/5 % CO2 incubator. The PBMC were then stained with Live/Dead Aqua (Invitrogen Life Technologies, Grand Island, NY), fixed and permeabilized (Invitrogen Life Technologies), and stained for pDC markers (CD123 and CD303) and cytokine production (IFN-α and TNF-α). Flow cytometry data was acquired on a FACSAria (BD Biosciences, San Diego, CA).
Cell culture and ELISAs
Human pDCs were isolated from the blood of healthy adult donors under a protocol approved by the UMMS Institutional Review Board. PBMC were isolated using Ficoll-Hypaque density centrifugation, and pDCs were positively selected from the PBMC using magnetic beads (Miltenyi Biotec, Auburn, CA). 5 × 104 pDCs were cultured in 96-well plates in 200 μl RPMI 1640, 10 % FCS, and 10 ng/ml rIL-3. 1 μM R-848 or 7.5 μg/ml CpG 2336 (Coley Pharmaceuticals, Wellesley, MA) was added to pDC cultures overnight in a 37 °C/5 % CO2 incubator; cell-free culture supernatants were collected for ELISAs at 18–24 h. IFN-α and TNF-α ELISAs (R&D Systems) were performed per the manufacturer’s instructions. All samples were assayed in duplicate. In some experiments, pDCs were pretreated for 1 h with dihydrotestosterone (DHT, Sigma-Aldrich) at the indicated concentrations.
The SPSS software package (version 19.0) was used for statistical analyses. Comparisons between two groups were performed using a two-tailed Mann–Whitney U test. Spearman’s correlation was also determined. P < 0.05 was considered significant. Values are presented as the median [95 % confidence interval (CI)].
Intracellular cytokine staining
Interferon regulatory factor 7
Peripheral blood mononuclear cells
Plasmacytoid dendritic cell
Respiratory syncytial virus
Systemic lupus erythematosus
Tumor necrosis factor-α
University of Massachusetts Medical School
World Health Organization.
The authors would like to acknowledge Rosario Z. Capeding, Luz Acosta, Linda Dexter-Fraser, and Ronald Banez for assistance with the infant clinical study and PBMC collection.
This work was supported by NIH/NIAID grants R01AI092105 (to J.P.W.) and U01AI065654 and R01AI091820 (to D.H.L.).
- McKenna K, Beignon AS, Bhardwaj N: Plasmacytoid dendritic cells: linking innate and adaptive immunity. J Virol. 2005, 79: 17-27. 10.1128/JVI.79.1.17-27.2005.PubMedPubMed CentralView ArticleGoogle Scholar
- Fitzgerald-Bocarsly P: Natural interferon-alpha producing cells: the plasmacytoid dendritic cells. Biotechniques. 2002, 22 (16–20): 24-29.Google Scholar
- Corbett NP, Blimkie D, Ho KC, Cai B, Sutherland DP, Kallos A, Crabtree J, Rein-Weston A, Lavoie PM, Turvey SE: Ontogeny of Toll-like receptor mediated cytokine responses of human blood mononuclear cells. PLoS One. 2010, 5: e15041-10.1371/journal.pone.0015041.PubMedPubMed CentralView ArticleGoogle Scholar
- Lan T, Putta MR, Wang D, Dai M, Yu D, Kandimalla ER, Agrawal S: Synthetic oligoribonucleotides-containing secondary structures act as agonists of Toll-like receptors 7 and 8. Biochem Biophys Res Commun. 2009, 386: 443-448. 10.1016/j.bbrc.2009.06.036.PubMedView ArticleGoogle Scholar
- Wagner H: The immunobiology of the TLR9 subfamily. Trends Immunol. 2004, 25: 381-386. 10.1016/j.it.2004.04.011.PubMedView ArticleGoogle Scholar
- Heil F, Ahmad-Nejad P, Hemmi H, Hochrein H, Ampenberger F, Gellert T, Dietrich H, Lipford G, Takeda K, Akira S: The Toll-like receptor 7 (TLR7)-specific stimulus loxoribine uncovers a strong relationship within the TLR7, 8 and 9 subfamily. Eur J Immunol. 2003, 33: 2987-2997. 10.1002/eji.200324238.PubMedView ArticleGoogle Scholar
- Jurk M, Heil F, Vollmer J, Schetter C, Krieg AM, Wagner H, Lipford G, Bauer S: Human TLR7 or TLR8 independently confer responsiveness to the antiviral compound R-848. Nat Immunol. 2002, 3: 499-PubMedView ArticleGoogle Scholar
- Berghofer B, Frommer T, Haley G, Fink L, Bein G, Hackstein H: TLR7 ligands induce higher IFN-alpha production in females. J Immunol. 2006, 177: 2088-2096.PubMedView ArticleGoogle Scholar
- Meier A, Chang JJ, Chan ES, Pollard RB, Sidhu HK, Kulkarni S, Wen TF, Lindsay RJ, Orellana L, Mildvan D: Sex differences in the Toll-like receptor-mediated response of plasmacytoid dendritic cells to HIV-1. Nat Med. 2009, 15: 955-959. 10.1038/nm.2004.PubMedPubMed CentralView ArticleGoogle Scholar
- Hughes GC, Thomas S, Li C, Kaja MK, Clark EA: Cutting edge: progesterone regulates IFN-alpha production by plasmacytoid dendritic cells. J Immunol. 2008, 180: 2029-2033.PubMedView ArticleGoogle Scholar
- Quigley CA: Editorial: the postnatal gonadotropin and sex steroid surge-insights from the androgen insensitivity syndrome. J Clin Endocrinol Metab. 2002, 87: 24-28. 10.1210/jc.87.1.24.PubMedGoogle Scholar
- Lockshin MD: Sex differences in autoimmune disease. Lupus. 2006, 15: 753-756. 10.1177/0961203306069353.PubMedView ArticleGoogle Scholar
- Barrat FJ, Meeker T, Gregorio J, Chan JH, Uematsu S, Akira S, Chang B, Duramad O, Coffman RL: Nucleic acids of mammalian origin can act as endogenous ligands for Toll-like receptors and may promote systemic lupus erythematosus. J Exp Med. 2005, 202: 1131-1139. 10.1084/jem.20050914.PubMedPubMed CentralView ArticleGoogle Scholar
- Li X, Xu Y, Ma L, Sun L, Fu G, Hou Y: 17beta-estradiol enhances the response of plasmacytoid dendritic cell to CpG. PLoS One. 2009, 4: e8412-10.1371/journal.pone.0008412.PubMedPubMed CentralView ArticleGoogle Scholar
- Pang S, Levine LS, Chow D, Sagiani F, Saenger P, New MI: Dihydrotestosterone and its relationship to testosterone in infancy and childhood. J Clin Endocrinol Metab. 1979, 48: 821-826. 10.1210/jcem-48-5-821.PubMedView ArticleGoogle Scholar
- Grino PB, Griffin JE, Wilson JD: Testosterone at high concentrations interacts with the human androgen receptor similarly to dihydrotestosterone. Endocrinology. 1990, 126: 1165-1172. 10.1210/endo-126-2-1165.PubMedView ArticleGoogle Scholar
- Meyer TE, Chu LW, Li Q, Yu K, Rosenberg PS, Menashe I, Chokkalingam AP, Quraishi SM, Huang WY, Weiss JM: The association between inflammation-related genes and serum androgen levels in men: the prostate, lung, colorectal, and ovarian study. Prostate. 2012, 72: 65-71. 10.1002/pros.21407.PubMedPubMed CentralView ArticleGoogle Scholar
- Tailor P, Tamura T, Ozato K: IRF family proteins and type I interferon induction in dendritic cells. Cell Res. 2006, 16: 134-140. 10.1038/sj.cr.7310018.PubMedView ArticleGoogle Scholar
- Hannah MF, Bajic VB, Klein SL: Sex differences in the recognition of and innate antiviral responses to Seoul virus in Norway rats. Brain Behav Immun. 2008, 22: 503-516. 10.1016/j.bbi.2007.10.005.PubMedPubMed CentralView ArticleGoogle Scholar
- Thompson DJ, Gezon HM, Hatch TF, Rycheck RR, Rogers KD: Sex distribution of Staphylococcus aureus colonization and disease in newborn infant. N Engl J Med. 1963, 269: 337-341. 10.1056/NEJM196308152690703.PubMedView ArticleGoogle Scholar
- Simoes EA: Environmental and demographic risk factors for respiratory syncytial virus lower respiratory tract disease. J Pediatr. 2003, 143: S118-S126. 10.1067/S0022-3476(03)00511-0.PubMedView ArticleGoogle Scholar
- Parcina M, Wendt C, Goetz F, Zawatzky R, Zahringer U, Heeg K, Bekeredjian-Ding I: Staphylococcus aureus-induced plasmacytoid dendritic cell activation is based on an IgG-mediated memory response. J Immunol. 2008, 181: 3823-3833.PubMedView ArticleGoogle Scholar
- Schlender J, Hornung V, Finke S, Gunthner-Biller M, Marozin S, Brzozka K, Moghim S, Endres S, Hartmann G, Conzelmann KK: Inhibition of toll-like receptor 7- and 9-mediated alpha/beta interferon production in human plasmacytoid dendritic cells by respiratory syncytial virus and measles virus. J Virol. 2005, 79: 5507-5515. 10.1128/JVI.79.9.5507-5515.2005.PubMedPubMed CentralView ArticleGoogle Scholar
- Hornung V, Schlender J, Guenthner-Biller M, Rothenfusser S, Endres S, Conzelmann KK, Hartmann G: Replication-dependent potent IFN-alpha induction in human plasmacytoid dendritic cells by a single-stranded RNA virus. J Immunol. 2004, 173: 5935-5943.PubMedView ArticleGoogle Scholar
- WHO Multicentre Growth Reference Study Group: WHO Child Growth Standards: Length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: Methods and development. 2006, World Health Organization, Geneva, (312 pages)Google Scholar
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