Contents

10 August 1990
Vol 249, Issue 4969

About The Cover

Immunofluorescence photomicrograph of vacuoles containing the parasite Toxoplasma gondii inside a Chinese hamster ovary cell stably transfected with murine Fc receptors. Infected cells were stained with an antibody to a lysosomal glycoprotein (lgp). Only parasites coated with antibody before internalization reside in lgp-stained vacuoles, indicating that route of parasite entry determines fusion competence of the vacuole. See page 641. [Photograph by Philippe Male, Yale University]