This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Khan, Z M Articles by Vanderberg, J P Search for Related Content PubMed PubMed Citation Articles by Khan, Z M Articles by Vanderberg, J P

 Previous Article  |  Next Article 

Infect Immun. 1992 January; 60(1): 264-270

Early hepatic stages of Plasmodium berghei: release of circumsporozoite protein and host cellular inflammatory response.

Department of Medical and Molecular Parasitology, New York University School of Medicine, New York 10016.

ABSTRACT

After injection of Plasmodium berghei sporozoites into Norway-Brown rats, we were able to localize these sporozoites and the early hepatic trophozoites developing from them in histological sections of the liver stained with a sensitive immunogold-silver procedure. Sporozoites invading hepatocytes released substantial quantities of circumsporozoite protein into the hepatocyte cytoplasm. This intrahepatic cytoplasmic distribution reached a maximal level at about 4 h post-sporozoite injection. As the hepatic parasites continued to differentiate, circumsporozoite protein became undetectable within the cytoplasm of the hepatocytes and became localized around the periphery of each parasite. There was generalized cellular inflammation within the liver of the host, which first became evident at around 4 h post-sporozoite injection and progressed to the formation of well-defined granulomas by 24 h. Such histopathological changes were not seen in rats injected with killed sporozoites, indicating that the cellular inflammation was induced by viable, infective sporozoites. We did not observe cellular infiltration specifically associated with any of the developing hepatic stages that we observed, even up to 28 h post-sporozoite inoculation. These results indicate that viable sporozoites induced rapid and generalized hepatic inflammation in host rats. However, sporozoites that successfully invaded hepatocytes and then proceeded to develop further did not appear to be the target of inflammatory cells until a period beginning at around 40 h post-sporozoite inoculation.