713 KINETICS OF IMMUNOGLOBULIN RELEASE BY THE BREAST MILK MACROPHAGE

The breast milk macrophage(MΦ)has been reported to release stored IgA over time.To determine the kinetics of immunoglobulin release,separate aliquots of MΦ from 9 healthy mothers were cultured serially for 7 days.Each culture contained 2×106MΦ suspended in 1 ml of media.The release of IgA into the media was quantitated using double antibody radioimmunoassays.To determine total cellular IgA at 0 time and 7 days,MΦ cultures were sonicated and ultracentrifuged.The cell pellet obtained was separated from the supernatant and resuspended in a volume of fresh media equal to the supernatant.These two solutions were then assayed for IgA content.Mean ±SEM IgA released into culture media after 0,3 & 7 days was 0.45±0.2,24.6±15.5,and 29.7±19 μg/ml.The mean ±SEM IgA measured in the sonicate pellet and sonicate supernatant at 0 time was 24.7±16.7 and 24.5±13.2 μg/ml as compared to 12.5±11 and 11.4±0.9μg/ml measured in the sonicate pellet and sonicate supernatant after 7 days incubation.The immunoglobulin released(y)per day(x)can be determined from the equation: