We previously demonstrated that certain biologic activities in human milk were partially blocked by antibodies directed against human tumor necrosis factor-a (TNF-α). In this study, immunochemical methods were used to verify the presence of TNF-α in human milk obtained during the first few days of lactation. Gel filtration revealed the presence of TNF-α by RIA in molecular weight fractions between 80 and 195 kD. TNF-α could not be detected consistently by conventional Western blotting or cytotoxic assays. Although immunoreactive bands were detected by a Western blot-125I protein A technique in TNF-α-positive fractions from gel filtration, those bands proved to be nonspecific. TNF-α in milk was reliably quantified by the competitive RIA. Those studies revealed that the concentrations of TNF-α in milk were 620 ± 183 pg/mL. Although RNA to TNF-α was detected in milk leukocytes by Northern blotting, little TNF-α was found in those cells before or after stimulation with N-formyl-/-methionyl-/-leucyl-/-phenylalanine or 4β-phorbol-12β-my-ristate-13a-acetate. The origin of this cytokine in human milk remains unclear. Nevertheless, this study suggests that TNF-α is present in early human milk in sufficient quantities to exert possible biologic effects upon the mammary gland of the mother or the immune system of the infant.
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health