Morphologic changes in the murine leukemia L5178Y cells treated with antibodies in the absence of complement activity

Murine leukemia L5178Y cells treated with antiserum in the absence of complement activity showed capping and endocytosis of surface receptors after 30 min and 3 hr, respectively. Electron microscopy revealed that the number of microvilli on the treated cells was decreased after 1 hr whereas mitochondrial damage, appearance of vesicles and autosome—cytosomes, and small numbers of cell ghosts with watery cytoplasm and nucleus occurred after 6 hr. At 24 hr, some cells were obviously dead or moribund while the majority showed similar changes to those that had been seen at 6 hr. In many cells polyribosomes had become disorganized, reflecting the previously reported inhibition of protein synthesis which occurred after 6 to 8 hr. By 48 hr, many more of the cells had died but the survivors appeared to be essentially normal, indicating recovery of cells from the growth inhibitory effect of antiserum.