Differential reactivity of salivary igA and igG against streptococcus mutans proteins in humans with different caries experience

ABSTRACT

Dental caries is an infectious disease which still constitutes a public health concern. It begins at an early age and is caused mainly Streptococcus mutans (S. mutans). The aim of this study was to characterize the salivary humor immune response to S. mutans proteins in patients with caries, with history of caries and without caries, in order to determine which S. mutans proteins participate in the immunological response in subjects with different caries experience. Saliva was collected by spontaneous salivation for 5 minutes from 60 subjects aged 18 to 30 years, classified according to their caries experience as without caries (Group I), with active caries (Group II) and with history of caries (Group III). The antigens derived from S. mutans by sonication were recognized by salivary IgA and IgG by Western Blot. The results showed that all the individuals studied recognized S. mutans proteins with molecular weights in the range of 8 to 191 kDa, with similar recognition profiles for salivary IgA and IgG. Subjects without caries recognized the 29 kDa protein, also known as S. mutans Antigen A, via salivary IgA, differing from patients with caries and history of caries, who recognized it via IgG. The protective response against S. mutans is mediated by IgA. To conclude, a differential response to the 29 kDa protein between study individuals may be indicative of resistance to dental caries and may have a protective role in the induction of IgA antibodies against dental caries, as found in the group without caries, in contrast to subjects with active caries and history of caries.

RESUMEN

La caries dental es una enfermedad infecciosa que continua siendo un problema de salud publica, inicia a temprana edad y es causada principalmente por Streptococcus mutans (S. mutans). El objetivo de este estudio fue caracterizar la respuesta inmune humoral salival, ante las proteinas de S. mutans, en pacientes con caries, historia de caries e individuos libres de caries, para asi establecer que proteinas de S. mutans participan en la respuesta inmunologica en los diferentes estadios de caries. La saliva de 60 individuos entre 18 y 30 anos de edad, clasificados de acuerdo al estado de caries libres de caries (grupo I), caries activa (grupo II) e historia de caries (grupo III), se colecto por salivacion espontanea durante 5 minutos. Los antigenos derivados de S. mutans por sonicacion, fueron reconocidos por IgA e IgG salivales por Western Blot. Los resultados mostraron que todos los individuos estudiados reconocen las proteinas de S. mutans en el rango de 8 a 191 kDa de peso molecular con perfiles de reconocimiento similares para IgA e IgG salival. Se encontro que los sujetos libres de caries reconocen por IgA salival la proteina de 29 kDa, tambien llamada Antigeno A de S. mutans, de manera diferente que los pacientes con caries e historia de caries quienes reconocieron la proteina via IgG. La respuesta protectora frente a S. mutans es mediada por IgA. En conclusion, una respuesta diferencial a la proteina de 29 kDa entre los individuos estudiados, puede ser indicativo de resistencia a la caries dental y tener un papel protector en la induccion de anticuerpos IgA frente a la caries dental, como se encontro en el grupo libre de caries, a diferencia de los sujetos con historia de caries y caries activa.