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Development of secretory immunity in breast fed and bottle fed infants
Insights
Breastfeeding boosts early infant immunity, with higher immunoglobulin levels in breastfed infants at 6 days. However, bottle-fed infants show increased immunoglobulin concentrations later, suggesting local antigens become the primary immune stimulator.
Area of Science:
- Immunology
- Pediatrics
- Neonatal Care
Background:
- Secretory immunoglobulins play a crucial role in mucosal immunity.
- Infant feeding methods, breastfeeding and bottle-feeding, may differentially impact immune development.
- Understanding early immune responses is vital for infant health and development.
Purpose of the Study:
- To compare immunoglobulin concentrations and specific antibody levels in breastfed versus bottle-fed infants.
- To investigate the impact of feeding method on secretory immunity from early neonatal period to 9 months.
- To determine the influence of breastfeeding on the development of mucosal immunity in infants.
Main Methods:
- Sequential collection of saliva and nasal secretions from 15 breastfed and 15 bottle-fed infants.
- Measurement of total immunoglobulin G (IgG), IgM, and IgA concentrations using radioimmunoassay.
- Quantification of specific antibodies to tetanus toxoid and Escherichia coli.
Main Results:
- Breastfed infants had higher total IgM, IgA, and IgA antibodies to E. coli at 6 days.
- All infants showed increased IgM and IgA concentrations by 6 weeks.
- Bottle-fed infants exhibited higher salivary IgA and IgM concentrations between 6 weeks and 9 months, but not in nasal secretions.
Conclusions:
- Breastfeeding provides a significant, but transient, enhancement of secretory immunity in the early neonatal period.
- By 6 weeks, local antigens appear to be the primary drivers of immunoglobulin production in respiratory mucosa.
- The study suggests that breastfeeding's immune-boosting effects on mucosal immunity are most pronounced in the initial neonatal phase.
Abstract:
Samples of saliva and nasal secretions were collected sequentially from 15 breast fed and 15 bottle fed infants on five occasions between 6 days and 9 months of age. Total immunoglobulin concentrations of G, M, and A classes, and class specific antibodies to tetanus toxoid and a pool of commensal strains of Escherichia coli were measured by solid phase radioimmunoassay and expressed per milligram of total protein. There were significant differences between feeding groups, which changed with age. Total IgM and IgA concentrations and IgA antibodies to E. coli were higher in the saliva and nasal secretions of breast fed infants at 6 days. There followed a rapid increase in IgM and IgA concentrations in secretions from all infants, and between 6 weeks and 9 months concentrations were higher in the saliva (but not in the nasal secretions) of the bottle fed group. There were no significant differences between the feeding groups for total IgG, specific G, M, and A antibodies to tetanus toxoid, and G and M antibodies to E. coli. These results suggest that breast feeding enhances secretory immunity in the early neonatal period only. By 6 weeks, local antigens are the main source of stimulation for production of immunoglobulin in the respiratory mucosa and thus may be obscuring any additional stimulation by growth factors in breast milk.