Little is known about subclass levels of IgA in serum or saliva of infants in the perinatal period. We have previously shown that very young infants are capable of responding to an experimental rotavirus vaccine with both serum and salivary IgA, and that small amounts of IgA are already detectable in cord blood of these infants. In the present study, total IgA1 and IgA2 antibodies in serum and saliva samples of some of these infants at birth, at 6 weeks of age, and at 12 weeks of age, were determined by a quantitative ELISA. Also, subclass‐specific IgA antibodies to the rotavirus group A common antigen were determined by ELISA. The ratio of average serum concentrations of IgA1 to IgA2 for 14 infants at 6 weeks of age was 19:1, while in saliva it was 5:1. Between 6 and 12 weeks of age levels of serum IgA1 increased by 25%, while levels of IgA2 did not increase perceptibly. Concentrations of IgA1 were higher in infant sera than in saliva, while concentrations of IgA2 were slightly higher in saliva than in serum. When calculated as specific ELISA units per mg IgA1, more salivary IgA1 was specific for rotavirus than serum IgA1. Further studies are needed to determine when infant IgA2 levels rise to values more characteristic of children and adults. This may be of significance for infant mucosal immunizations if secretory IgA2, more resistant to bacterial proteases than IgA1, is required for efficient defence of the respiratory and intestinal tracts.
SUMMARYSerum and salivary responses of 95 infants to either a standard (4 x 10''plaque-forming units (PFU), 47 neonates) or a high dose (4 x 10^ PEU, 48 neonates) of tetravalent reassortant rhesus rotavirus vaccine (administered at 2 days and at 6 weeks of age) were evaluated in a double-blind clinical trial. Serum and salivary IgA antibodies to the rotavirus group A common antigen were determined by ELISA and radioimmunoassay (RIA). Serum neutralizing antibodies to rhesus rotavirus were determined by fluoreseent foeus reduction assay. No significant differences in responses to the high versus standard dose were noted in serum or saliva. Response was influenced by cord blood antibodies. All infants who were cord blood-negative for rhesus rotavirus neutralizing antibodies (nine who received the standard dose and 20 who received the higher dose) had serum responses, compared with 42 H)"A. ofthose who were cord blood-positive. The scrum response rate recorded for babies with cord blood neutralizing titres > 1000 was 44' ;-^>. Infants being bottle fed had a higher serum response rate than did babies being breast fed exclusively. If serum and salivary responses were combined, the response rate reached 80% for bottle fed infants. Thus, determination of serum responses alone underestimates vaccine 'take' in infants, and more so in highly endetnie areas thati in areas subject only to sporadic outbreaks. However, determination of salivary responses in newborn breastfed infants may be inaccurate, due to possible persistence of antibodies derived frotn colostrum or breast milk.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.