title: The effect of breast-feeding on proliferation by infant lymphocytes in vitro.
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 at 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 at the two earliest ages studied (6 days and 6 wk). Responses to mitogens which predominantly affect B cells, such as pokeweed mitogen and Staphylococcus aureus (Cowan), were similar in both feeding groups at 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.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D001942:Breast Feeding; D002453:Cell Cycle; D002455:Cell Division; D006801:Humans; D007223:Infant; D007225:Infant Food; D007231:Infant, Newborn; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000187:drug effects; D010835:Phytohemagglutinins / Q000494:pharmacology; D011043:Pokeweed Mitogens / Q000494:pharmacology; D013211:Staphylococcus aureus; D013745:Tetanus Toxoid / Q000494:pharmacology
chemical_list: D010835:Phytohemagglutinins; D011043:Pokeweed Mitogens; D013745:Tetanus Toxoid