Human milk cell migration and production of monocyte chemotactic factor: lack of activity

The lymphocytes of human breast milk have been previously shown to be immunologically competent while the monocytes have been described as actively motile in some reports but not in another. Cells were separated from milk samples collected by lactating women 2 to 9 days postpartum. Milk cell migration and production of the lymphokine, monocyte chemotactic factor, by milk cells were assayed using membrane filters. Milk cells were poorly motile although prior culturing improved their migratory ability. Cell-free milk was chemotactic for blood monocytes. Chemotactic factor production was detected in only two of 16 phytohemagglutinin-stimulated milk cell cultures.