OBJECTIVES Anti-citrullinated protein antibodies (ACPA) have been shown to cause platelet activation in vitro, through the low-affinity immunoglobulin G (IgG) receptor (FcγRIIa) on platelets. Platelet activation via engagement of FcγRIIa results in proteolytic cleavage and shedding of platelet specific glycoprotein VI (GPVI) which can be detected in the plasma as soluble GPVI (sGPVI). We hypoth...

OBJECTIVE Mast cells may play a role in rheumatoid arthritis (RA), but activation of human mast cells in autoimmune settings has been little studied. Toll-like receptors (TLR) and Fcγ receptors (FcγR) are important receptors for cellular activation in the joint, but expression and stimulation of these receptors in human mast cells or the functional interplay between these pathways is poorly und...

Despite recent treatment improvements, multiple myeloma remains an incurable disease. Since antibody-dependent cell-mediated cytotoxicity is an important effector mechanism of daratumumab, we explored the possibility of improving daratumumab-mediated cell-mediated cytotoxicity by blocking natural killer cell inhibitory receptors with the human monoclonal anti-KIR antibody IPH2102, next to activ...

Plasmacytoid dendritic cells (pDC) expressing FcγRIIa are antigen-presenting cells able to link innate and adaptive immunity and producing various cytokines and chemokines. Although highly restricted, they are able to replicate HIV-1. We determined the activity of anti-HIV-1 neutralizing antibodies (NAb) and non-neutralizing inhibitory antibodies (NNIAb) on the infection of primary pDC by HIV-1...

The interactions of therapeutic antibodies with fragment crystallizable γ (Fcγ) receptors and neonatal Fc receptors (FcRn) are measured in vitro as indicators of antibody functional performance. Antibodies are anchored to immune cells through the Fc tail, and these interactions are important for the efficacy and safety of therapeutic antibodies. High-throughput binding studies on each of the hu...

The importance of human Fc receptors in immune regulation is well known. Their role is critical not only in the recruitment of cellular effector functions but also in regulating the balance in the periphery between autoimmunity and tolerance. Despite their central importance, there is a dearth of literature on controlled numeric comparisons in affinities of antibody subclasses for gamma recepto...

PURPOSE AS1402 is a humanized immunoglobulin G1 antibody that targets the aberrantly glycosylated antigen MUC1, which is overexpressed in 90% of breast tumors and contributes to estrogen-mediated growth and survival of breast cancer cells in vitro by modulating estrogen receptor (ER) activity. Aromatase inhibitors have been reported to enhance antibody-dependent cell-mediated cytotoxicity elici...

Activating Fc gamma receptors (FcγRs) in hematopoietic cells serve to remove antibody-opsonized antigens, including dengue virus (DENV), from systemic circulation. While neutralizing antibody concentrations provide humoral immunity, cross-reactive or sub-neutralizing levels of antibody can result in antibody-dependent enhancement of DENV infection that increases overall viral burden. Recently, ...

Genetic polymorphisms of the Fc gamma receptors (FcγR) IIa and IIIa have been implicated in the rate of HIV-1 disease progression, but results are inconsistent. We aimed to determine the association between these polymorphisms and disease progression in a cohort of HIV-1 seroconverters from Mombasa, Kenya. Neither FcγRIIa nor FcγRIIIa genotypes were predictive of set point viral load, viral loa...