Effects of antibodies, trypsin, and trypsin inhibitors on susceptibility of neonates to rotavirus infection.
Levels of antirotaviral secretory immunoglobulin A were measured by enzyme-linked immunosorbent assay in colostrum and milk samples collected daily for the first 5 days postpartum from 49 mothers breast-feeding their infants. The trypsin-inhibitory capacity of these lacteal secretion samples was assessed by their ability to inhibit the hydrolysis of alpha-N-benzoyl-DL-arginine-p-nitroanilide by trypsin. Stools passed by these breast-fed infants and by an additional 43 bottle-fed infants were pooled by individual and examined by electron microscopy for rotavirus. Stool trypsin levels were estimated with the gelatin hydrolysis test. Breast-fed infants were significantly less likely to become infected with rotavirus and showed significantly lower stool tryptic activity than did bottle-fed infants. Breast-fed infants who did not excrete rotavirus over the 5-day period received milk of significantly higher antirotaviral secretory immunoglobulin A or trypsin-inhibitory capacity or both than breast-fed infants who were infected with rotavirus. A case of probable maternal rotavirus infection during pregnancy, producing greatly elevated lacteal antirotaviral secretory immunoglobulin A levels lasting for 2 years, was detected. Results of this study suggest that both antibodies and trypsin inhibitors in human milk can be associated with the protection of neonates against rotavirus infection in the first 5 days of life.
D003126:Colostrum / Q000032:analysis; D005243:Feces / Q000201:enzymology; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis*; D007071:Immunoglobulin A, Secretory / Q000032:analysis*; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000276:immunology*; D008895:Milk, Human / Q000032:analysis / Q000276:immunology; D012087:Reoviridae / Q000276:immunology*; D012088:Reoviridae Infections / Q000276:immunology*; D012401:Rotavirus / Q000276:immunology*; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000032:analysis*
D007070:Immunoglobulin A; D007071:Immunoglobulin A, Secretory; D014361:Trypsin Inhibitors; D014357:Trypsin