Cell surface antigens of neonatal monocytes are selectively impaired in basal expression, but hyperresponsive to lipopolysaccharide and zymosan

• Published in: Journal of reproductive immunology Vol. 136; p. 102614
• Main Authors: Hikita, Norikatsu, Cho, Yuki, Tachibana, Daisuke, Hamazaki, Takashi, Koyama, Masayasu, Tokuhara, Daisuke
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier B.V 01.11.2019
• Subjects: Adult; Antigens, Surface - blood; Antigens, Surface - immunology; Cord blood; Female; Fetal Blood - immunology; Fetal Blood - metabolism; Flow Cytometry; Humans; Infant, Newborn; Innate immunity; Lipopolysaccharides - pharmacology; Male; Monocyte; Monocytes - immunology; Monocytes - metabolism; Neonate; Toll-like receptor; Zymosan - pharmacology; Neonate; APC; Cord blood; Monocyte; Innate immunity; TLR; Toll-like receptor; DC; mAb
• ISSN: 0165-0378; 1872-7603
• DOI: 10.1016/j.jri.2019.102614

•Neonates have limited innate immune responses to infection.•We compared cord blood (CD14+CD16high) and adult (CD14+CD16intermediate) monocytes.•Cord blood monocytes had low basal expression of MHC class II, CD80, and CD11b.•TLR4 or TLR2/6 stimulation increased the antigens more in cord than adult monocytes.•TLR agonists may have utility as vaccine adjuvants in infants. Toll-like receptors (TLRs) are important components of the innate immune system, but how neonatal TLR-mediated immune responses differ from those of adults is unknown. We aimed to clarify the TLR-mediated expression profiles of cell surface antigens related to antigen presentation in neonates. CD14-positive monocytes were isolated from human cord blood and adult peripheral blood and then stimulated with lipopolysaccharide (LPS; TLR4 agonist) or zymosan (TLR2/6 agonist) or left unstimulated. Expression levels of the surface antigens major histocompatibility (MHC)-class II, CD80, CD86, CD11b, CD11c, CD14, and CD16 were then evaluated by flow cytometry. Cord blood CD14+CD16high monocytes (CBM) showed significantly lower basal levels of MHC-class II, CD80, and CD11b than adult blood CD14+CD16intermediate monocytes (ABM) (P < 0.01, P < 0.001, P < 0.001, respectively). LPS stimulation enhanced expression of MHC class II, CD80, and CD11b significantly more in CBM than in ABM (P < 0.001, P < 0.01, P < 0.01, respectively), resulting in levels that did not differ between CBM and ABM. Zymosan stimulation also enhanced expression of MHC class II, CD86, CD11b, and CD11c significantly more in CBM than in ABM (P < 0.001, P < 0.01, P < 0.001, P < 0.01, respectively), resulting in levels of CD86 and CD11c that did not differ in CBM and ABM. However, MHC class II, CD80, and CD11b remained significantly higher in ABM than in CBM (P < 0.05, P < 0.01, P < 0.05, respectively). These data indicate that CBM and ABM have distinct phenotypes and responses to stimulation.