The Effect of Breast-Feeding on Proliferation by Infant Lymphocytes in Vitro

Abstract

ABSTRACT. The effect of breast-feeding on the development of lymphocyte responsiveness in infants has been studied. Peripheral blood mononuclear cells from 15 breast-and 15 bottle-fed infants were obtained sequentially between 6 days and 9 months of age. A number of agents were used to stimulate the cells in vitro and the resulting proliferative responses were compared between the two feeding groups. A hanging drop microculture system using serum-free medium, enabled spontaneous proliferation and proliferative responses to several stimuli ( T and B cell mitogens, allogeneic lymphocytes, and antigen) to be studied a t a range of cell concentrations and days of culture. Significant age-related differences were found between the responses of cells from the two feeding groups. Spontaneous proliferation and proliferative responses to the T cell mitogen phytohaemagglutinin and the antigen tetanus toxoid were significantly greater in the breast-fed group a t the two earliest ages studied (6 days and 6 wk). Responses to mitogens which predominantly affect B cells, such a s pokeweed mitogen and Staphylococcus aureus (Cowan), were similar in both feeding groups a t this age. In contrast, from 3 to 9 months of age, responses of cells from bottle-fed infants were significantly greater to all stimuli than responses from breast-fed infants. One possible explanation for the higher level of proliferation by cells from newborn breast-fed infants, is that these infants may absorb the cell-growth factors and lymphokines known to be present in human colostrum and milk. These factors may stimulate T cells and/or their precursors in vivo. The subsequent greater responsiveness of peripheral blood mononuclear cells from the bottle-fed group a t 3 to 9 months of age appears to be due to a higher level of antigenic stimulation in vivo in this group. This could result from the greater intake of cow milk proteins or from the absence of the passive protective effect of the antimicrobial components in human milk. Breast-fed infants have a lower incidence of infections than bottle-fed infants (1-3). This has been attributed to a passive protective role of antimicrobial compounds in human milk, such as secretory IgA, acting locally within the gut of the newborn infant (4-6). More recently, interest has developed in other factors in colostrum and milk, such as epidermal growth factor (7, 8), interferon (9, 1 O), and prostaglandins ( 1 1, 12), which can influence cell growth and differentiation in vitro. It is possible that these growth factors and lymphokines in milk may actively enhance the development of the immune system of the breastfed infant, although an in vivo role for milk lymphokines has not yet been demonstrated. To investigate whether these lymphokines might be having an effect in vivo on the immune system of the breast-fed infant, we have studied the development of immune responses in breast-and bottle-fed infants sequentially from 6 days to 9 months of age.Mononuclear cell proliferation in vitro has frequently been used to assess ...

Influence of Feeding Formula and Breast Milk Fortifier on Lymphocyte Subsets in Very Low Birth Weight Premature Newborns

“…Hawkes et al [22] documented higher numbers of CD4+ lymphocytes and lower numbers of CD8+ cells in their formula-fed babies compared to their HM-fed infants. Stephens et al [24] made these same observations in 6-week-old cell cultures from formula-fed infants. They proposed that this could be explained by increased antigenic stimulation in this group, and based this argument on three factors: (a) increased exposure to cow's milk proteins in the formula-fed babies; (b) deficiency of direct antimicrobial features of HM in the formula fed group, and (c) earlier bacterial translocation in babies fed formula than in those fed HM.…”

“…In contrast, however, Hawkes et al [22] observed no difference in B-cell numbers in HM-fed versus formula-fed babies. In experiments involving 6-day and 6-week-old cell cultures from babies fed HM or formula, Stephens et al [24] found no differences between the 2 groups with respect to spontaneous and stimulated B-cell proliferation. However, Juto [25] showed that adding colostrum or HM to spleen cell cultures induced B-cell proliferation.…”

Intracellular and plasma cytokine profile in neonates born to non-atopic parents: the impact of breast feeding

“…In addition, previous studies, most including older infants, showed that breast feeding had a significant impact on various aspects of lymphocyte function [22,30]. Previous studies by Stevens et al [30] showed that lymphocyte proliferating responses were significantly higher in the BF infants during the first 6 weeks of life and lower thereafter as compared to those in the FF infants. Pabst et al [22] reported significantly lower T-cell activation and lower IFN-gamma production either at baseline or following stimulation by tetanus toxoid or Candida albicans at 12 months of age.…”

“…Thymic size has been reported to be greater in infants still being breast fed at the age of 10 months [14]. In addition, previous studies, most including older infants, showed that breast feeding had a significant impact on various aspects of lymphocyte function [22,30]. Previous studies by Stevens et al [30] showed that lymphocyte proliferating responses were significantly higher in the BF infants during the first 6 weeks of life and lower thereafter as compared to those in the FF infants.…”

Tumor Necrosis Factor-α in Human Milk

“…DISCUSSION This is one of the first immunochemical demonstrations of a cytokine in human milk and the first report of substantial amounts of TNF-a in human milk. A number of other studies have reported effects of mammalian milks on the growth and development of T and B lymphocytes that were attributed to the possible presence of cytokines (28)(29)(30)(31)(32). However, no studies were performed to determine if cytokines were present.…”