Electron Microscopy of Intracellular Protozoa
Abstract
Verapamil, a calcium antagonist, has recently been shown to reverse chloroquine resistance in malarial parasites in vitro. In collaboration with Major Milhous and his associates, we studied morphological changes associated with this phenomenon using chloroquine-sensitive and resistant clones of P. falciparum. While the administration of 6.3 x 10 -8M chloroquine had little morphological effect on the chloroquine-resistant strain, the combination of chloroquine and verapamil resulted in typical chloroquine-related food vacuolar swelling with increased amounts of granular matrix. Secondary morphological changes included degeneration of nuclei, mitochondria and other organelles. These effects appeared similar to those in the chloroquine-sensitive strain of P. falciparum treated with chloroquine alone or with the chloroquine/verapamil combination. Therefore, our results support the suggestion that verapamil reverses chloroquine resistance in malarial parasites. We also performed an experiment on ultrastructural localization of protective antigens of P. falciparum by post embedding immunoelectron microscopy in collaboration with Col. J. Chulay of WRAIR. The 101 kDa antigen recognized by monoclonal 3D5 is synthesized by mature trophozoites and young schizonts and appears in the culture medium when schizont rupture occurs in normal culture medium. Post embedding immunoelectron microscopy indicated that the antigen recognized by MAb 3D5 was present at the surface of schizonts within electron-dense material in the parasitophorous vacuole and at the surface of individual merozoites within schizont-infected cells.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1988
- Accession Number
- ADA203527
Entities
People
- Masamichi Aikawa
Organizations
- Case Western Reserve University