Immunology and Pathology of Arena Virus Infections.
Final rept. 31 Jan 90-30 Jan 92,
TEXAS UNIV AT GALVESTON
Pagination or Media Count:
Pichinde Virus PIC is the animal model for human Lassa Fever. The pathogenic mechanisms were examined by comparing a virulent guinea pig GP adapted PIC strain, adPIC and the GP avirulent prototype PIC strain PIC3739. ADPIC replicated to higher titers than PIC3739 in macrophages infected in vivo and in vitro. Lethal infections were associated with pronounced shifts in visceral macrophage distribution. Tumor necrosis factor TNF - like bioactivity levels increased in the serum of adPIC but not PIC3739 infected GPs. Spleen TNF activity rose during the first week after infection by both viral strains. However, neither in vitro nor in vivo infected macrophages by either virus produced more TNF. Peritoneal macrophages explanted from adPIC infected GP day 1 1 showed augmented TNF production after LPS stimulation as compared with PIC3739 infected or uninfected cells. We now theorize that TNF secretion patterns relate to the level of virus infection or replication and there appear to be structural differences in these two viruses that may account for different pathogenicities. Characterization of these structural differences will be important in developing potential model vaccine strains. Finally, results are also presented that support the theory that adPIC infection is associated with a progressive suppression of lymphocyte responses.
- Medicine and Medical Research