Local Antibodies to α-Casein and β-Lactoglobulin in the Saliva of Infants

Abstract

ABSTRACT. Salivary antibodies were studied in 112 infants between 1 day and 8 yr of life. SIgA anticasein was present from birth in breast-fed and bottle-fed infants. Bottle-feeding resulted in significantly higher concentrations of SIgA anticasein at 3 wk to 3 months of life as compared to breast-feeding. Salivary anticasein declined toward the end of the 1st yr and was present in less than half of the children older than 1 yr. Salivary anti-@-lactoglobulin was also present at birth in some infants. Levels increased slightly over the following 3 months but remained low. Only a minority of older children had this antibody in their saliva. Transplacentally acquired IgG protects the newborn infant against most systemic infections. During the immediate postnatal period some of this IgG can be recovered from mucosal membranes and may contribute to mucosal defense mechanisms. SIgA, the major secretory immunoglobulin, has been detected in saliva as early as 7 days of life and adult levels were present at 4 wk in 92% of infants (I, 2). Secretory antibodies have been shown to represent an immune response against replicating and nonreplicating antigens on mucosal surfaces and act to exclude such antigens from penetrating mucosal membranes.Cow's milk proteins are among the first antigens encountered by many human neonates. The systemic immune response to these proteins has been characterized in healthy term infants, in premature infants as well as in children and adults during health and disease (3-8).Since milk proteins are continuously presented to the local immune system of the gut and since these proteins have repeatedly been implicated in the pathogenesis of atopic disease it was of interest to study local antibody formation to the two major cow's milk proteins, a-casein and P-lactoglobulin during the 1st yr of life. MATERIALS AND METHODSnot relating to the immune system. In infants, unstimulated saliva was obtained by gentle suctioning with a soft rubber tube over 10-15 min. Saliva was obtained at least I h after the last meal to avoid contamination of the samples with milk. Saliva was heated for 20 min at 5 1" C, centrifuged at 5000 x g for 15 min and kept at -20" C until analyzed. Each individual was studied on a single occasion. Among the ten I-to 5-day-old neonates, four were fully breast-fed, three were bottle-fed, and three received mixed feedings. In the 3-wk to 4-month-old group 10 infants were fully breast-fed; among the remaining 2 1 bottlefed infants, three were still receiving some additional breast milk and 1 1 had received breast milk for an average of 4 wk. After 4 months of age all except two infants were exclusively bottle-fed. Antibody determinations.Antibodies against a-casein and Plactoglobulin of the IgA-isotype were determined by a direct ELISA as published previously (5, 8). Microtiter plates (Nunc Laboratories, Roskilde, Denmark) were coated with a-casein or @-lactoglobulin at concentrations of 20 pg/ml. Rabbit IgG-antibody against human SC was purchased from Nordic Immunological Laboratories...

Total and allergen‐specific immunoglobulin A levels in saliva in relation to the development of allergy in infants up to 2 years of age

“…The number of saliva samples with detectable levels of IgA to Fel d 1 tended to increase with age, while the opposite was observed for BLG‐specific IgA. The latter finding supports the results of a previous study [10], while the kinetics of IgA production in saliva to an inhalant allergen has not been studied previously. The different kinetics of IgA responses to BLG and Fel d 1 is similar to the development of IgG subclass responses, showing decreasing levels of food allergen‐specific IgG subclass antibodies [2, 11] and increasing levels of inhalant‐specific IgG with age [2].…”

Elevated Concentrations of Salivary Secretory Immunoglobulin A Anti-Cow’s Milk Protein in Newborns at Risk of Allergy

“…It confirms the observation of a previous investigation from our own laboratory [6] and from a group of Swedish investigators [7] who described SIgA antibodies in neonates which were directed against poliovirus and bacterium Escherichia coli.…”

“…The other 50% of tested samples contained less than 10% SIgM as compared to the SIgA activity. As previously described [6], SIgM to milk protein appears to play a minor role in neonatal sa liva.…”

“…Although concentra tions of total SIgA in serum or secretions were mini mal or below the limit of detection in early studies, re cent work has repeatedly demonstrated the presence 1 Supported by the Deutsche Forschungsgemeinschaft, Grant Rl 345/4-5. 2 We thank Mrs. Renate Warsideh for her excellent secretarial as sistance of specific SIgA and SIgM to viral, bacterial and milk protein antigens in the saliva of neonates [6,7], As IgA does not pass the placenta [9], the origin of these antibodies is not entirely clear. It is reasonable to assume, however, that they represent an early pro tection for the neonate's mucus membranes against invading organisms and potential allergens.…”

Human α-Lactalbumin and Bovine β-Lactoglobulin Absorption in Premature Infants

“…Secretion of IgA in the mucosa is induced to inhibit absorption of foreign antigens and to protect the host from harmful effects (20). Specific mucosal antibodies appear within 2 wk of exposure to new antigens (21). Our study was designed to detect the effects of these events on the permeation of BLG and ALA. Only small effects were seen.…”