FIG. 4.

Recognition by pooled human intestinal and serum anti-LC3 IgA antibodies of synthetic peptides based on the amino acid sequences of LC3 epitopes 3 and 7. Ten overlapping peptides were synthesized based on the sequence of epitope 3 and 2 peptides were synthesized based on epitope 7. Intestinal (triangles) and serum (circles) IgA antibodies were obtained from subjects cured of ALA with concurrent infection (black); gray symbols, seropositive, asymptomatic PCR-positive subjects; open symbols, seronegative PCR-negative control subjects. Peptides 2, 9, 11, and 12 were recognized by intestinal and serum IgA antibodies from all subjects, compared to the cutoff point established by seronegative controls. Peptides 2, 9, and 11 were recognized by serum IgA antibodies from ALA subjects and fecal and serum IgA antibodies from asymptomatic infected seropositive subjects.