Junin Virus Infection of Guinea Pigs: Immunohistochemical and Ultrastructural Studies of Hemopoietic Tissue

Abstract

An association between viral antigens, cytopathic effect (CPE) and viral titers in blood and lymphoid tissues suggests a direct CPE of Junin virus on the lymphopoietic organs of guinea pigs infected with 10(3) 50% lethal doses of the XJ prototype strain. After seven days of infection, all lymphoreticular organs had infectivity titers higher than those for blood. Virus was recovered from bone marrow and lymph nodes at day 5 after infection; peak titers were obtained from bone marrow, spleen, and lymph nodes after day 10. Granular specific fluorescence was detected in the cytoplasm of reticular monocytes after day 7; megakaryocytes showed positive fluorescence, but specific staining of other lymphoid cells was not observed. Necrosis of bone marrow, lymph nodes, and spleen was observed after day 9. CPE consisted of overdevelopment of reticuloendoplasmic cisterne of reticulomonocytes and myeloblasts. Typical Junin virus particles were observed. Reticular cells were gradually destroyed, and simultaneous necrosis of surrounding lymphoid cells was observed.

Cytogenetic Effect of Two Strains of Junin Virus in the Guinea Pig

“…Al though the biological properties of the virus have been extensively analyzed [6][7][8], almost no data exist on its cytogenetic effect. Thus far…”

“…Thus far Guinea pigs reproduce the main features of the human disease when infected experiment ally with the XJ strain of virus. This strain produces 100% mortality in 14 days, and lymphotropism of the virus is demonstrated by the high viral titers and the presence of viral antigens and CPE in lymphoid tissue [7,8], On the contrary, the XJ-CI3 strain is attenuated for this host and induces a rapid humoral immune response. In this report we present data regard ing the in vivo cytogenetic effect of these two strains of Junin virus on the bone marrow chromosomes of guinea pigs.…”

Viral Strain Dependent Differences in Experimental Argentine Hemorrhagic Fever (Junin Virus) Infection of Guinea Pigs

“…This has also been reported for guinea pigs infected with the prototype XJ strain of Junin [8] and for rhesus ma caques infected with P3790, but not with P3406 [20]. Lesions in the bone marrow are not consistently found in human AHF [21], but, however, they are not a rare finding.…”

“…The same time point in both figure 1 and table II represents the same guinea pig. Based on preliminary studies in our labora tory and on the studies of Eisner et al [6] and Carballal et al [8], the primary sites for virus isolation in Junin-infected guinea pigs are lymph nodes, spleen, bone marrow, brain, and serum. These were examined from each animal, and those sites positive for virus are shown in figure 1.…”

“…Disadvantages of this model, however, are cost, scarcity, and the large size of the animals, restricting their util ity to very specialized studies. Much of the current knowledge of AHF pathogenesis has been derived from studies with guinea pigs, and most of these have been conducted with a single strain of Junin virus, the prototype XJ strain [6,8].…”