Intestinal immunoglobulin a response to naturally acquired enterotoxigenic Escherichia coli in US travelers to an endemic area of Mexico.
BACKGROUND
Simple methods for detecting secretory immunoglobulin A (sIgA) immune responses following natural enteric infection and oral immunization are needed.


METHODS
Fourteen students from the United States acquiring enterotoxigenic Escherichia coli (ETEC) diarrhea in Mexico were studied for fecal immunoglobulin A (IgA) response to their homologous infecting ETEC and to heat-labile (LT) toxin of ETEC using Dot-Blot microfiltration and enzyme-linked immunosorbent assay (ELISA) methods. Paired stool samples were collected on the day of presentation and 5 days later.


RESULTS
Twelve of 14 (86%) patients with ETEC diarrhea (5 heat-stable [ST]/LT positive, 4 LT-only, and 5 ST-only) developed sIgA antibodies directed against their homologous ETEC and 6 (66%) of the 9 patients harboring ST/LT or LT-only strains developed sIgA LT-antibody responses. Single fecal samples from 9 healthy controls were negative for ETEC specific antibodies.


CONCLUSIONS
Patients with diarrhea due to noninvasive ST/LT ETEC and LT ETEC commonly produce a specific sIgA antibody response early in the illness. We feel that the methods employed will be useful to detect antibodies during natural infection by enteric pathogens and following oral enteric vaccine administration.
Estrada-García
M T
MT
Center of Infectious Diseases, The University of Texas School of Public Health, Houston, Texas, USA.
Jiang
Z-D
ZD
Adachi
J
J
Mathewson
J J
JJ
DuPont
H L
HL
D000917:Antibody Formation; D000942:Antigens, Bacterial / Q000276:immunology; D003967:Diarrhea / Q000276:immunology* / Q000382:microbiology; D004768:Enterotoxins / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D004927:Escherichia coli Infections / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000276:immunology*; D008800:Mexico / Q000453:epidemiology; D014195:Travel; D014481:United States
D000942:Antigens, Bacterial; D004768:Enterotoxins; D007070:Immunoglobulin A