Interleukin 8 in the Human Colostrum

We investigated the postpartum changes in colostral interleukin (IL) 8 concentrations during the first 3 postpartum days and examined the IL-8 production of colostral cells at the levels of both protein and mRNA. Colostrum samples were obtained from healthy mothers after full-term delivery. Colostrum, supernatants, and cell lysates of cultured colostral cells were assayed for IL-8 by enzyme-linked immunosorbent assay. Reverse-transcription polymerase chain reaction was used to test uncultured colostral cells for the production of IL-8 mRNA. The colostral IL-8 concentrations, especially high on day 1 postpartum, declined abruptly during the first 3 postpartum days (mean 19.7, 10.0, and 3.0 ng/ml on days 1, 2 and 3 postpartum, respectively). Colostral cells apparently produced and secreted IL-8 in in vitro culture without stimulant, although in smaller quantities than with lipopolysaccharide stimulation. The majority of uncultured colostral cell samples expressed IL-8 mRNA, suggesting a role of colostral cells, at least in part, as a source of colostral IL-8.