Degradation of immunoglobulin G by periodontal bacteria

Abstract

Several subgingival microorganisms were tested for their ability to utilize human immunoglobulin G (IgG) as a substrate for growth. This was done using a protein-free chemically defined medium, supplemented with IgG. Stimulation of growth was observed for Capnocytophaga ochracea, Porphyromonas asaccharolytica, Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, Prevotella oralis, Lactobacillus catenaforme and Streptococcus intermedius. Immunoelectrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a protein assay demonstrated that P. intermedia and P. endodontalis completely degraded the protein chains of IgG. Partial breakdown of IgG was observed for P. asaccharolytica and C. ochracea, whereas P. oralis cleaved the IgG heavy chain, yielding Fc and Fab fragments. All these bacteria utilized IgG as a substrate for growth. Binding studies using an enzyme-linked immunosorbent assay, revealed complete loss of in vitro antigen-antibody binding capacity after incubation of specific IgG with P. endodontalis and partial loss of binding with P. intermedia, P. gingivalis, C. ochracea or Fusobacterium nucleatum. Degradation or inactivation of IgG by oral bacteria is thought to be important in the causation of polymicrobial infections.

Characterization of immunoglobulin G‐degrading proteases of Prevotella intermedia and Prevotella nigrescens

“…In a previous study, we demonstrated the ability of Porphyromonas and Prevotella species to use IgG as the sole source of amino acids while growing in a chemically defined medium (11). Here, using a relatively rich medium, we detected growth enhancement of P. intermedia and P. nigrescens by up to 130%.…”

“…Although P. intermedia may be less virulent than Porphyromonas gingivalis (30), it produces an array of virulence factors (21), of which the capacity to degrade immunoglobulins is thought to be important. Bacteria with this ability can provide themselves (8,11) and other bacteria (27) with nutrients while simultaneously impeding host defense (3,6). Several laboratories have isolated and characterized P. gingivalis proteases (4,7,20,29), but less attention has been paid to those of P. intermedia.…”

An Orthologue of Bacteroides fragilis NanH Is the Principal Sialidase in Tannerella forsythia

“…A number of periodontal bacteria are known to exploit host sialylated glycoproteins as a nutrient source. For example, immunoglobulin G, which is abundant in gingival crevicular fluid, can support the growth of P. gingivalis, Prevotella oralis, and a number of other periodontal pathogens (20). The NanH of B. fragilis is important for growth in vivo: sialidase-deficient mutants of B. fragilis have impaired growth in a rat pouch model (14).…”

IgG and IgA subclass mRNA-bearing plasma cells in periodontitis gingival tissue and immunoglobulin levels in the gingival crevicular fluid

“…Immunohistochemistry is an established technique for protein detection, but staining for immunoglobulin may be unreliable due to the high background staining caused by non-specific binding to other immunoglobulins within the tissues [15] and with serumderived immunoglobulins which bathe the tissues [6]. In addition, the detection of immunoglobulin proteins in vivo presents several technical difficulties because of degradation by neutrophil elastase [16] and oxidants [17] in inflamed sites as well as by immunoglobulin-degrading proteases from periodontal bacteria [18,19]. Our attempts to localize immunoglobulin in gingival tissues using MoAbs have been disappointing due to the excessive background staining thought to be due to the systemic and local soluble immunoglobulin presence.…”