Induction of antibodies by Staphylococcus aureus nasal colonization in young children

Abstract

In order to develop novel antistaphylococcal strategies, understanding the determinants of carriage and how humans respond to Staphylococcus aureus exposure is essential. Here, the primary S. aureus-specific humoral immune response and its association with nasal colonization was studied in young children. Sera from 57 colonized or non-colonized children, serially collected at birth and at 6, 14 and 24 months, were analysed for IgG, IgA and IgM binding to 19 staphylococcal proteins, using flow cytometry-based technology. The antibody responses showed extensive inter-individual variability. On average, the levels of antistaphylococcal IgA and IgM increased from birth until the age of 2 years (p <0.05), whereas the levels of IgG decreased (p <0.001). Placentally transferred maternal IgG did not protect against colonization. In colonized children, IgG and IgA levels for a number of proteins were higher than in non-colonized children. At both 14 and 24 months, the levels of IgG against chemotaxis inhibitory protein of S. aureus (at 24 months; median fluorescence intensity, 4928 vs. 24, p <0.05), extracellular fibrinogen-binding protein (987 vs. 604, p <0.05), and iron-responsive surface determinant H (62 vs. 5, p <0.05) were significantly higher in colonized children. The levels of IgA against CHIPS, IsdH and IsdA were higher (p <0.05). Therefore, CHIPS, Efb, IsdA and IsdH seem to play a role in nasal colonization of young children.

Clearance of Staphylococcus aureus Nasal Carriage Is T Cell Dependent and Mediated through Interleukin-17A Expression and Neutrophil Influx

“…HIV-infected patients with a CD4 ϩ T-cell count of Յ200/l have an increased prevalence of persistent colonization (10). In addition, colonized children have significantly higher levels of IgA and IgG against S. aureus proteins than do noncolonized children (11). Despite the evidence provided by these studies, the specific immunological mechanisms for clearance of S. aureus nasal carriage are undefined.…”

“…Previous studies have shown a potential role for antibody-mediated immunity in clearance. IgA and IgG antibodies have been shown to increase in nasally colonized children (11). Additionally, antistaphylococcal antibody levels are higher in persistent carriers than in noncarriers (18).…”

Natural Antibodies against Several Pneumococcal Virulence Proteins in Children during the Pre-Pneumococcal-Vaccine Era: the Generation R Study

“…The Wilcoxon signed rank tests and Mann-Whitney U tests were used for the same type of analyses described previously (34).…”

The Generation R Study: design and cohort update 2012

“…Observations of parent-child interaction and behaviour, such as executive function, heart rate variability, infant-parent attachment, moral development, and compliance with mother and child have been performed at the ages of 14, 36 and 48 months and with father and child at the age of 48 months [240,241]. Biological materials have been collected, including bacterial colonization measured by nasal-and nasopharyngeal swabs at the ages of 1.5, 6, 14 and 24 months, cortisol day rhythm measured by repeated salivary samples at the age of 14 months and, if parents give consent, blood samples at the ages of 6, 14 and 24 months [242][243][244][245][246][247][248][249][250][251].…”