A novel technique for detecting IgA coated potentially pathogenic microorganisms in the human intestine.

This paper describes a novel method for detecting immunoglobulin A (IgA) coated potentially pathogenic microorganisms (PPMs) in the human intestine. Essentially, the technique consists of 2 phases: one in which IgA coated bacteria are detected by immunofluorescence and a second in which these bacteria are subcultured in situ and subsequently identified. In this way transient bacteria are differentiated from resident bacteria. These results show that the resident bacteria are coated with IgA. Resident microorganisms are always highly concentrated in the digestive tract. These results strengthen the hypothesis that only the high antigen concentrations achieved by a large number of resident bacteria are capable of IgA induction.