Postinoculation PMPA Treatment, but Not Preinoculation Immunomodulatory Therapy, Protects against Development of Acute Disease Induced by the Unique Simian Immunodeficiency Virus SIVsmmPBj

Abstract

The fatal disease induced by SIVsmmPBj4 clinically resembles endotoxic shock, with the development of severe gastrointestinal disease. While the exact mechanism of disease induction has not been fully elucidated, aspects of virus biology suggest that immune activation contributes to pathogenesis. These biological characteristics include induction of peripheral blood mononuclear cell (PBMC) proliferation, upregulation of activation markers and Fas ligand expression, and increased levels of apoptosis. To investigate the role of immune activation and viral replication on disease induction, animals infected with SIVsmmPBj14 were treated with one of two drugs: FK-506, a potent immunosuppressive agent, or PMPA, a potent antiretroviral agent. While PBMC proliferation was blocked in vitro with FK-506, pig-tailed macaques treated preinoculation with FK-506 were not protected from acutely lethal disease. However, these animals did show some evidence of modulation of immune activation, including reduced levels of CD25 antigen and FasL expression, as well as lower tissue viral loads. In contrast, macaques treated postinoculation with PMPA were completely protected from the development of acutely lethal disease. Treatment with PMPA beginning as late as 5 days postinfection was able to prevent the PBj syndrome. Plasma and cellular viral loads in PMPA-treated animals were significantly lower than those in untreated controls. Although PMPA-treated animals showed acute lymphopenia due to SIVsmmPBj14 infection, cell subset levels subsequently recovered and returned to normal. Based upon subsequent CD4+ cell counts, the results suggest that very early treatment following retroviral infection can have a significant effect on modifying the subsequent course of disease. These results also suggest that viral replication is an important factor involved in PBJ-induced disease. These studies reinforce the idea that the SIVsmmPBj model system is useful for therapy and vaccine testing.

Gene Chromosomal Organization and Expression in Cultured Human Neurons Exposed to Cocaine and HIV-1 proteins gp120 and tat: Drug Abuse and NeuroAIDS

“…Of many animal models, the SIV-rhesus macaque also yields important information related to NeuroAIDS disease (31,32). The monkey animal model using SIV recapitulates NeuroAIDS in great part (33) and infection of CNS is supported by animal model studies as well. A neurovirulent clone of SIV was isolated that causes CNS lesions.…”

Post-exposure prophylaxis of HIV infection.German-Austrian guidelines

“…Grundsätzliche und mit Vorbehalt zu interpretierende, tierexperimentelle Untersuchungen (9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) lassen zusätzlich vermuten, dass -der Wirkmechanismus einer PEP nicht allein auf einer vollständigen Blockade der initialen Infektion beruht, -zumindest ein Teil der Wirksamkeit auf einer durch die Medikamente geschützten Entwicklung einer kompetenten zellulären Immunantwort beruhen könnte, -die Wirksamkeit der PEP vom Beginn und der Dauer der Medikamentengabe ebenso wie von der Auswahl der Medikamente abhängig ist, -die Verlängerung der Behandlungsdauer möglicherweise einen verzögerten Behandlungsbeginn in Grenzen kompensieren kann, -bei unvollständigem Schutz eine Verzögerung der Infektion (Virämie, Antikörperbildung) um ca. 1-3 Wochen nach Ende der Prophylaxe zu erwarten ist.…”