Irene K. Berezesky

ENHANCEMENT OF ADENOVIRUS GROWTH IN AFRICAN GREEN MONKEY KIDNEY CELL CULTURES BY SV40.

Summary SV40 enhances the growth of adenovirus 12 in African green monkey kidney (AGMK) cell cultures. In the absence of SV40, adenovirus 12 produces CPE; however, after 72 hours, less than 1% of the cells contain adenovirus particles by electron microscopy, and titrations show no increase in virus. When similar cultures are infected with both SV40 and adenovirus 12, after 72 hours 75% of the cells contain adenovirus particles and there is an increase in virus by titration. A similar enhancement of the growth of adenovirus 5 in AGMK cultures by SV40 has been observed. The development of progressive adenovirus-type cytopathic changes without demonstrable adenovirus particles in cells of AGMK cultures infected with adenoviruses alone suggests the possibility of some type of incomplete virus formation which is able to go to completion in the presence of SV40.

Ultrastructure of a rat cytomegalovirus

Abstract A cytomegalovirus isolated from Panamanian rats was examined by electron microscopy. Capsid structure of the virions in negatively stained preparations appeared identical to human cytomegalovirus and other viruses of the herpes family. In thin sections, the naked nucleocapsid measured slightly larger (138 nm) than herpes-type and cytomegaloviruses previously reported. Development of the virus was observed in rat kidney and hamster kidney cell cultures. Periodic fibrils were observed in the nuclei of infected rat kidney cells, and virus particles accumulated in unusually large cytoplasmic aggregates.

Biochemical, Morphologic, and Gytogenetic Studies of Leukocytes Growing in Continuous Culture from Normal Individuals and from Patients with Cystinosis

Extract: Continuous leukocyte cultures were established from the blood of three siblings with classical nephropathic cystinosis and from their mother. The cells from patients with cystinosis (CC) contained at least 15− to 20-fold more cystine than cultured leukocytes from normal individuals (NC). The transport of cystine-35S into CC was similar to uptake into NC when tested at pH 5.0 and pH 7.4.The cultured CC could not be distinguished by ultrastructure from NC Crystalline inclusions which could easily have been mistaken for cystine were observed in the lysosome of a normal cell. The modal number of chromosomes in CC and NC lines was 46. There was a marked degree of aneuploidy. Tetraploidy was present in 3.8–9.6% of metaphases. Structural rearrangements and breaks were seen in all cell lines.Speculation: Continuous leukocyte cultures may prove a useful experimental tool for further studies of the basic metabolic derangement responsible for abnormal intracellular accumulations of cystine in cystinotic cells (CC). The cultures are a convenient source of relatively large amounts of pure cellular material for investigative use. Because they grow in suspension, cultured leukocytes are well suited for investigation of transport phenomena in normal human cells (NC) as well as those with genetic diseases. The absence of a defect in the uptake of cystine at pH 5.0 in CC fails to support the hypothesis of a lysosomal transport abnormality for cystine in these cells, yet cannot be regarded as firm refutation of that hypothesis. Elucidation of the basic metabolic defect in cystinosis may require studies of the enzymology and transport systems of isolated lysosomes; such transport studies may have formidable technical problems.The demonstration of intralysosomal crystals which could easily have been mistaken for cystine in one line of cultured NC emphasizes the need for great caution in assigning pathophysiologic significance to any rare crystalline bodies seen only in occasional lysosomes or other organelles of CC.The chromosome abnormalities, and perhaps the capacity to proliferate, of continuously cultured leukocytes may be related to infection with herpes-like virus, as has been previously suggested.

Virus: Mixed Infection with Herpes Simplex and Simian Virus 40.

Mixed infection, the infection of a single cell by two distinguishable viruses, has been demonstrated by electron microscopy in cultures of African green monkey kidney cells after inoculation with simian virus 40 and herpes simplex. Mixed infection occurs rarely when the two viruses are inoculated simultaneously, but if herpes is inoculated 24 hours after SV40 both viruses are found in the same nucleus in about 5 percent of intact cells.