Proximity to livestock farms and COVID-19 in the Netherlands, 2020-2021.

Objectives: In the Netherlands, during the first phase of the COVID-19 epidemic, the hotspot of COVID-19 overlapped with the country's main livestock area, while in subsequent phases this distinct spatial pattern disappeared. Previous studies show that living near livestock farms influence human respiratory health and immunological responses. This study aimed to explore whether proximity to livestock was associated with SARS-CoV-2 infection.

The multiple facets of FcRn in immunity.

The neonatal Fc receptor, FcRn, is best known for its role in transporting IgG in various tissues, providing newborns with humoral immunity, and for prolonging the half-life of IgG. Recent findings implicate the involvement of FcRn in a far wider range of biological and immunological processes, as FcRn has been found to bind and extend the half-life of albumin; to be involved in IgG transport and antigen sampling at mucosal surfaces; and to be crucial for efficient IgG-mediated phagocytosis. Herein, the function of FcRn will be reviewed, with emphasis on its recently documented significance for IgG polymorphisms affecting the half-life and biodistribution of IgG3, on its role in phagocyte biology, and the subsequent role for the presentation of antigens to lymphocytes.

Staphylococcus aureus formyl peptide receptor-like 1 inhibitor (FLIPr) and its homologue FLIPr-like are potent FcγR antagonists that inhibit IgG-mediated effector functions.

To evade opsonophagocytosis, Staphylococcus aureus secretes various immunomodulatory molecules that interfere with effective opsonization by complement and/or IgG. Immune-evasion molecules targeting the phagocyte receptors for these opsonins have not been described. In this study, we demonstrate that S.

Competition for FcRn-mediated transport gives rise to short half-life of human IgG3 and offers therapeutic potential.

Human IgG3 displays the strongest effector functions of all IgG subclasses but has a short half-life for unresolved reasons. Here we show that IgG3 binds to IgG-salvage receptor (FcRn), but that FcRn-mediated transport and rescue of IgG3 is inhibited in the presence of IgG1 due to intracellular competition between IgG1 and IgG3. We reveal that this occurs because of a single amino acid difference at position 435, where IgG3 has an arginine instead of the histidine found in all other IgG subclasses.

FcRn: an IgG receptor on phagocytes with a novel role in phagocytosis.

Here, we report that the MHC class I-related neonatal Fc receptor (FcRn) is expressed within azurophilic and specific granules of neutrophils and relocates to phagolysosomes on phagocytosis of IgG-opsonized bacteria. We found FcRn to enhance phagocytosis in a pH-dependent manner which was independent of IgG recycling. IgG-opsonized bacteria were inefficiently phagocytosed by neutrophils from beta2M knock-out or FcRn alpha-chain knock-out mice, which both lack expression of FcRn.

Working mechanism of immunoglobulin A1 (IgA1) protease: cleavage of IgA1 antibody to Neisseria meningitidis PorA requires de novo synthesis of IgA1 Protease.

Neisseria meningitidis secretes a protease that specifically cleaves the hinge region of immunoglobulin A1 (IgA1), releasing the effector (Fc) domain of IgA1 from the antigen binding (Fab) determinants. Theoretically, the remaining Fab fragments can block pathogen receptors or toxins and still provide protection. Here, we describe binding of V-gene-matched human IgA1 and IgA2 to PorA of strain H44/76.

Central role of complement in passive protection by human IgG1 and IgG2 anti-pneumococcal antibodies in mice.

Streptococcus pneumoniae is an important cause of morbitity and mortality worldwide. Capsule-specific IgG1 and IgG2 Abs are induced upon vaccination with polysaccharide-based vaccines that mediate host protection. We compared the protective capacity of human recombinant serogroup 6-specific IgG1 and IgG2 Abs in mice deficient for either leukocyte FcR or complement factors.