Some Properties of Human Colostral Cells

Summary The morphological and some functional properties of the characteristic large monanuclear cells of human colostrum have been studied in vitro. In the 25 samples examined their number varied between 2 × 104 and 6 × 106cells per ml. In Leishman‐stained smears these cells measured up to 40 μ in diameter. Their nuclei were rounded, oval or irregular in shape and were surrounded by either a thick rim of basophilic cytoplasm with a few fat‐filled vacuoles only or, more often, by an even more abundant cytoplasm packed with globular fat The cells were shown to adhere to glass and to survive in culture for a period of 8 days or longer. The cultured cells spread out on the glass and by 4 days many cells with extremely long cytoplasmic processes (up to 100 μ) were seen. A number of multi‐nucleated cells (giant cells) which were considered to have arisen by cytoplasmic fusion rather than by amitotic division were also observed after 2 days in culture. The cultured cells were shown to take up large amounts of colloidal carbon, carbonyl iron and colostral fat particles when these substances were added to the culture medium. Cells in fresh monolayers formed directly from colostrum and cells cultured for periods of up to 8 days strongly took up baboon macrophage‐cytophflic antibody. We failed to detect IgA or other immunoglobulins on the surface of colostral cells in fresh monolayers formed from colostrum, or on cultured cells re‐exposed to human serum or colostrum using the highly sensitive mixed antiglobulin procedure.