Evidence for long-term memory of the mucosal immune system: milk secretory immunoglobulin A against Shigella lipopolysaccharides.
Although the common mucosal immune system has generally been considered to have only short-term memory, recent data suggest that long-term memory exists for Shigella virulence plasmid antigens. Because such antigens might cross-react with environmental antigens, we investigated milk for the persistence of antibodies to the specific Shigella lipopolysaccharide (LPS) antigens. Enzyme-linked immunosorbent assays to detect secretory immunoglobulin A (sIgA) against Shigella flexneri and Shigella sonnei LPS in milk samples were developed; 15 random milk samples tested on different days correlated from one day to the next (P = 0.0001). Of 18 Mexican mothers, 18 (100%) had one or more milk samples positive for anti-S. flexneri LPS, 14 (78%) had one or more milk samples positive for anti-S. sonnei LPS, and 14 (78%) had one or more milk samples positive for both. Of 27 Houston mothers, 16 (59%) had one or more milk samples positive for anti-S. flexneri LPS, 7 (26%) had one or more milk samples positive for anti-S. sonnei LPS, and 5 (19%) had one or more milk samples positive for both. Mexican mothers were significantly more likely than Houston mothers to have at least one sample with a positive titer for anti-S. flexneri LPS (P less than 0.02) and at least one sample with a positive titer for anti-S. sonnei LPS (P less than 0.002). Although the Houston women had a lower rate of titer positivity for both Shigella species, the rate was too high to be consistent with short-lived mucosal immunity. It is unlikely that 18 of the 27 Houston women had shigellosis during or just prior to lactation. The data suggest that there exists a long-term hormonally driven memory in the secretory immune system for Shigella spp.
Hayani
K C
KC
Department of Pediatrics, University of Texas Medical School, Houston 77030.
Guerrero
M L
ML
Ruiz-Palacios
G M
GM
Gomez
H F
HF
Cleary
T G
TG
D000907:Antibodies, Bacterial / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007107:Immune System / Q000276:immunology; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D007156:Immunologic Memory; D008070:Lipopolysaccharides / Q000276:immunology; D008895:Milk, Human / Q000276:immunology*; D009092:Mucous Membrane / Q000276:immunology; D012760:Shigella / Q000276:immunology*; D012763:Shigella flexneri / Q000276:immunology; D012764:Shigella sonnei / Q000276:immunology; D013997:Time Factors
D000907:Antibodies, Bacterial; D007071:Immunoglobulin A, Secretory; D008070:Lipopolysaccharides