The appearance of lecithin- 32 P, synthesized from lysolecithin- 32 P, in phagosomes of polymorphonuclear leukocytes.

Rabbit polymorphonuclear leukocytes ingesting paraffin oil particles stabilized with albumin, converted more lysolecithin-(32)P (added to the medium as an albumin complex) to cellular lecithin than did control cells. Almost all of the increment in leukocyte lecithin-(32)P is found in association with the isolated phagocytic vacuoles. About half of lecithin-(32)P of granulocytes incubated first with lysolecithin-(32)P and then reincubated with paraffin particles in a nonradioactive medium is transferred from a sedimentable (presumably membrane) fraction to the phagosomes. Isolated phagosomes or granules by themselves are capable of acylating lysolecithin. The main source of lysolecithin-(32)P for synthesis of cellular lecithin-(32)P, however, appears to be extracellular rather than lysolecithin-(32)P within the cytoplasm or the phagocytic vacuole. We interpret our findings therefore as indicating that lecithin-(32)P in the phagosomes derives chiefly from the outer membrane.