TITLE:
Periodontitis and Inflammation: Plasma High Titer Naturally Occurring Anti-Glucan Antibodies Form Immune Complex with Streptococcus mutans Antigen
AUTHORS:
Genu George, Molly Antony, Jaisy Mathai, Padinjaradath S. Appukuttan
KEYWORDS:
Streptococcus mutans, Anti-β-Glucan Antibody (ABG), Dextran Binding Immunoglobulins (DIg), Immune Complexes
JOURNAL NAME:
Modern Research in Inflammation,
Vol.5 No.3,
August
8,
2016
ABSTRACT: Atheromatous plaques
usually contain antigens of the periodontitis-causing bacteria Streptococcus mutans though molecular mechanism of this
incorporation remains unknown. Since vascular adhesion and inflammatory
potential of Immune Complexes (IC) are known we investigated the naturally
occurring plasma antibodies that recognize major antigens from S. mutans. S. mutans-binding plasma proteins
(SMBP) prepared by affinity chromatography on a column of heat-killed S. mutans could recognize α- and β-linked glucose in dextran and
yeast respectively but not galactose in
glycoproteins. SMBP contained only three proteins, each corresponding in
electrophoretic mobility to standard plasma IgG, IgA or IgM. The major
positively and negatively charged protein antigens (PSMAg and NSMAg) isolated
from S. mutans by electrophoresis and ion exchange
chromatography respectively were recognized sugar-reversibly by the anti-β-glucan
antibody (ABG) and though less avidly, by the dextran-binding immunoglobulin
(DIg) in normal plasma. NSMAg addition resulted in near doubling of IC-bound
immunoglobulins in immunoglobulin-rich fraction of plasma. IC isolated from
above fraction after NSMAg addition had substantially more IgA and IgM content
than total plasma immunoglobulins. IC formation by NSMAg was significantly
inhibited by ABG- and DIg-specific sugars or by selective withdrawal of ABG or
DIg from plasma. ABG and DIg being relatively high titer plasma antibodies IC
formation with them suggested a possible route for vascular adhesion and damage
by S. mutans and its antigens. Further, high IgA
content of these ICs indicated their susceptibility to tissue uptake through
cell surface galectin-1 for which IgA is the lone immunoglobulin ligand.