Targeting of Porphyromonas gingivalis with a bispecific antibody directed to FcalphaRI (CD89) improves in vitro clearance by gingival crevicular neutrophils.

Phagocytosis and killing of pathogens by polymorphonuclear neutrophils (PMN) from gingival crevicular fluid (GCF) is diminished in chronic periodontitis patients. As an approach to improve targeting of PMN toward a periodontopathogen, Porphyromonas gingivalis, the efficacy of a bispecific antibody (BsAb) directed against both recombinant 130 kDa hemagglutinin domain (r130k-HMGD) of P. gingivalis, and PMN Fc receptor (FcR) was evaluated.

Mac-1 (CD11b/CD18) as accessory molecule for Fc alpha R (CD89) binding of IgA.

IgA, the principal ligand for FcalphaRI, exists in serum as monomeric IgA and at mucosal sites as secretory IgA (SIgA). SIgA consists of dimeric IgA linked by joining chain and secretory components. Human polymorphonuclear leukocytes (PMN) and mouse PMN transgenic for human FcalphaRI exhibited spreading and elicited respiratory burst activity upon interaction with either serum or SIgA.

Activity of human IgG and IgA subclasses in immune defense against Neisseria meningitidis serogroup B.

Both IgG and IgA Abs have been implicated in host defense against bacterial infections, although their relative contributions remain unclear. We generated a unique panel of human chimeric Abs of all human IgG and IgA subclasses with identical V genes against porin A, a major subcapsular protein Ag of Neisseria meningitidis and a vaccine candidate. Chimeric Abs were produced in baby hamster kidney cells, and IgA-producing clones were cotransfected with human J chain and/or human secretory component.

Pneumococcal capsular polysaccharide-specific IgA triggers efficient neutrophil effector functions via FcalphaRI (CD89).

Specific anti-capsular polysaccharide IgG is believed to be important for protection against infection by Streptococcus pneumoniae. Significant IgA responses have been observed after vaccination with pneumococcal vaccines, but the role of this isotype in anti-pneumococcal host defense is unclear. Here, it is shown that purified serum IgA specific for pneumococcal capsular polysaccharides can initiate efficient cellular effector functions, such as phagocytosis, via interaction with the myeloid IgA receptor, FcalphaRI (CD89).

Effective phagocytosis and killing of Candida albicans via targeting FcgammaRI (CD64) or FcalphaRI (CD89) on neutrophils.

Invasive fungal infections are an increasing problem for immunocompromised patients. As an approach to improve targeting of polymorphonuclear leukocytes (PMNL) toward Candida albicans, the effect of bispecific antibodies (BsAbs) directed against C. albicans and either FcalphaRI or FcgammaRI was evaluated.

Factor V Leiden, antiphospholipid antibodies and thrombosis in systemic lupus erythematosus.

Thromboembolic complications are frequently observed in patients with systemic lupus erythematosus (SLE). Significant associations have been reported between these complications and the presence of antiphospholipid antibodies, notably the lupus anticoagulant and anticardiolipin antibodies. Factor V Leiden is a genetic disorder associated with an increased risk of venous thrombosis.

The plasma concentration of soluble Fc-gamma RIII is related to production of neutrophils.

Fc gamma RIII (the CD16-antigen), a low-affinity receptor for IgG, is expressed by neutrophils, natural killer lymphocytes and macrophages. A soluble form of Fc gamma RIII has been identified in human plasma. This soluble form of Fc gamma RIII (sFc gamma RIII) originates from release by neutrophils.