Pro-inflammatory adiponectin in pediatric-onset multiple sclerosis

Background: Being obese is associated with both increased risk of developing multiple sclerosis (MS) and greater MS disease activity. Objectives: The objective of this study is to investigate levels and potential pathophysiologic contribution of serum adipose-hormones (adipokines) in pediatric-onset MS. Methods: Following a Luminex adipokine screen, adiponectin (APN) and its isoforms were quantified by enzyme-linked immunosorbent assay (ELISA) in 169 children with incident acquired demyelinating syndromes (ADS), prospectively ascertained as having either MS or other forms of inflammatory central nervous system (CNS) demyelination. The effect of recombinant APN and APN-containing sera was assessed on functional responses of normal human peripheral blood myeloid and T cells and on human CNS-derived microglia. Results: Compared to other cohorts, children with MS harbored higher serum APN levels, principally driven by higher levels of the low-molecular-weight isoform. Recombinant APN and pediatric MS serum-induced APN-dependent pro-inflammatory activation of CD14+ monocytes and of activated CD4+ and CD8+ T cells (both directly and indirectly through myeloid cells). APN induced human microglia activation while inhibiting their expression of molecules associated with quiescence. Conclusions: Elevated APN levels in children with MS may contribute to enhanced pro-inflammatory states of innate and adaptive peripheral immune responses and breach CNS-resident microglia quiescence, providing a plausible and potentially targetable mechanism by which APN contributes to MS disease activity.

Antibody-Dependent Cellular Cytotoxicity against Primary HIV-Infected CD4+T Cells Is Directly Associated with the Magnitude of Surface IgG Binding

Antibody (Ab)-dependent cellular cytotoxicity (ADCC) is thought to potentially play a role in vaccine-induced protection from HIV-1. The characteristics of such antibodies remain incompletely understood. Furthermore, correlates between ADCC and HIV-1 immune status are not clearly defined. We screened the sera of 20 HIV-1-positive (HIV-1+) patients for ADCC. Normal human peripheral blood mononuclear cells were used to derive HIV-infected CD4+T cell targets and autologous, freshly isolated, natural killer (NK) cells in a novel assay that measures granzyme B (GrB) and HIV-1-infected CD4+T cell elimination (ICE) by flow cytometry. We observed that complex sera mediated greater levels of ADCC than anti-HIV-1 envelope glycoprotein (Env)-specific monoclonal antibodies and serum-mediated ADCC correlated with the amount of IgG and IgG1 bound to HIV-1-infected CD4+T cells. No correlation between ADCC and viral load, CD4+T cell count, or neutralization of HIV-1SF162or other primary viral isolates was detected. Sera pooled from clade B HIV-1+individuals exhibited breadth in killing targets infected with HIV-1 from clades A/E, B, and C. Taken together, these data suggest that the total amount of IgG bound to an HIV-1-infected cell is an important determinant of ADCC and that polyvalent antigen-specific Abs are required for a robust ADCC response. In addition, Abs elicited by a vaccine formulated with immunogens from a single clade may generate a protective ADCC responsein vivoagainst a variety of HIV-1 species. Increased understanding of the parameters that dictate ADCC against HIV-1-infected cells will inform efforts to stimulate ADCC activity and improve its potency in vaccinees.