ANTIBODIES TO ESCHERICHIA-COLI AND SHIGELLA-FLEXNERI IN MILK FROM UNDERNOURISHED MOTHERS - STUDIES ON SODIUM DODECYL SULFATE-POLYACRYLAMIDEGEL ELECTROPHORESIS-SEPARATED ANTIGENS

Analysis of IgA, IgM, and IgG antibodies against Escherichia call O6, its lipopolysaccharide (LPS), and Shigella flexneri were performed in the milk of moderately undernourished Guatemalan women receiving eithe r a low or a high calorie supplement, using SDS-PAGE. As expected, the immunostaining analysis of milk antibodies showed that IgA was the pr edominant isotype in both groups. Concerning the other Igs, antibodies against O6 LPS were mainly of the IgM isotype, whereas IgG antibodies were more prominent than ISM against the bacterial whole cell prepara tions. Seven to nine distinct bands, ranging in molecular mass from 13 .5 to 109 kD were selected for each antigen to compare the milk antibo dies between the two groups of women. After a 20-wk supplementation pe riod, the ISA and IgG antibodies to the E. coli, O6 LPS, and S. flexne ri were not found negatively affected by a low calorie intake. A signi ficantly lower immunostaining intensity was, however, obtained for the low calorie intake group regarding the IgM antibody activity against four high molecular mass bands of the E. coli whole cell preparation. A decreased immunostaining intensity-was also found in the same group for IgM antibodies against two bands of E. coli O6 LPS when analyzing paired samples collected at d 0 and wk 20. No differences were found f or IgM antibodies against any of the S. flexneri antigens. In conclusi on, the results suggest that low calorie intake does not significantly affect the production of milk IgA antibodies to E. coli and S. flexne ri antigens in these women. Still, IgM antibodies against certain prot eins and LPS molecules of E. coli may be decreased. IgG antibodies, al though also present in milk, seemed to be directed mainly against bact erial proteins and not to LPS.