Natural Immunoreactivity of Secretory IgA to Indigenous Strains of Streptococcus mutans From Chinese Spousal Pairs.
BACKGROUND
Dental caries is a well-known biofilm-mediated disease initiated by Streptococcus mutans, which should infect and colonize in a milieu perfused with components of the mucosal immune system. Little is known, however, regarding the relationship between the natural secretory IgA activity and S. mutans of a variety of diverse genotypes.


OBJECTIVE
The current study aimed to use spousal pairs to investigate the natural immunoreactivity of salivary secretory IgA to different genotype strains of S. mutans.


METHODS
Indigenous strains were characterized from nine spousal pairs using polymerase reaction chain (PCR) and arbitrarily primed polymerase chain reaction (AP-PCR) by genotype monitoring. Unstimulated submandibular/sublingual secretions were collected and the concentrations of secretory IgA were determined by the enzyme-linked immunosorbent assay (ELISA). Each saliva sample was examined by Western blot to analyze the immunoreactivity of naturally occurring salivary secretory IgA antibodies for his/her own indigenous strain, spouse's strain and reference strains including S. mutans GS-5 and Ingbritt (C).


RESULTS
The results showed that naturally induced salivary IgA antibodies against S. mutans were present in all subjects. Almost all subjects had the similar individual immunoblotting profiles to different genotype strains.


CONCLUSIONS
The current study indicated that the immunoreactivity of secretory IgA might have no direct correlation with the colonization of indigenous flora and rejection of exogenous strains in adults. The relationship of microbes, host and dental caries should be in the light of coevolved microecosystem as a whole, but not caused by one factor alone.
The State Key Laboratory Breeding Base of Basic Science of Stomatology, Hubei Province and Key Laboratory of Oral Biomedicine (Wuhan University), Ministry of Education, Wuhan, China.
Min
M
Nie
Department of Implantology, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
Dong
D
Chen
The State Key Laboratory Breeding Base of Basic Science of Stomatology, Hubei Province and Key Laboratory of Oral Biomedicine (Wuhan University), Ministry of Education, Wuhan, China.
Zhenyan
Z
Gao
The State Key Laboratory Breeding Base of Basic Science of Stomatology, Hubei Province and Key Laboratory of Oral Biomedicine (Wuhan University), Ministry of Education, Wuhan, China.
Xinyu
X
Wu
The State Key Laboratory Breeding Base of Basic Science of Stomatology, Hubei Province and Key Laboratory of Oral Biomedicine (Wuhan University), Ministry of Education, Wuhan, China.
Tong
T
Li
Colonization; Genotype; Immunoglobulin A; Indigenous Flora; Streptococcus mutans