TITLE:
Total IgA and IgA reactivity to antigen I/II epitopes in HLA-DRB1*04 positive subjects
AUTHORS:
V. Wallace McCarlie, James K. Hartsfield Jr, Janice S. Blum, Carlos González-Cabezas, Judith R. Chin, George J. Eckert, Lorri A. Morford, Mark D. Pescovitz, Henry Rodriguez, Margherita Fontana, Richard L. Gregory
KEYWORDS:
Dental Caries; Streptococcus mutans; I/II; IgA; Immunomodulation; Immunogenetics; HLA-II; DRB1; DRB1*04
JOURNAL NAME:
Open Journal of Immunology,
Vol.3 No.3,
September
18,
2013
ABSTRACT: Bacterial
adherence to the acquired dental pellicle, important in dental caries (caries),
is mediated by receptor-adhesins such as salivary agglutinin binding to Streptococcus mutans antigen I/II
(I/II). Ten selected I/II epitopes were chosen to determine their reactivity to
human salivary IgA. Previous studies suggested that a specific HLA biomarker
group (HLA-DRB1*04) may have differential influence of immune responses to
I/II. However, it was not known whether secretory IgA (SIgA) responses to the
selected epitopes from HLA-DRB1*04 positive subjects were different compared to
controls, or across other caries-related factors such as total IgA (TIgA).
Thirty-two total subjects were matched according to HLA type, gender, ethnicity
and age. HLA genotyping, oral bacterial, immunoglobulin and antibody analyses
were performed. A large observed difference emerged with regard to the natural immune reservoir of TIgA in HLA-DRB1*04 positive
subjects, specifically, a 27.6% reduction compared to controls. In contrast to
all other epitopes studied, HLA-DRB1*04 positive subjects also exhibited
reduced reactivity to I/II epitope 834-853. HLA-DRB1*04 positive subjects
exhibited lower specific SIgA activity/TIgA to 834-853 and also a lower
specific reactivity to 834-853/whole cell S.
mutans UA159. Furthermore, HLA-DRB1*04 positive subjects exhibited lower
responses to I/II in its entirety. The large observed difference in TIgA and
the 834-853 reactivity pattern across multiple measures suggest potentially
important connections pertaining to the link
between HLA-DRB1*04 and caries.