Pathogenesis and Immune Responses in Newborn African Green Monkeys (Cercopithecus aethiops) Inoculated with Simian Immunodeficiency Virus (SIVagm)

Background: Simian immunodeficiency viruses (SIVs) are diverse group of viruses that naturally infect a wide range of African primates, including African Green Monkeys (AGMs). It has been shown that in vivo passage of SIV in rhesus macaque results in selection of pathogenic virus that causes Simian Acquired Immunodeficiency Syndrome. However, adult AGMs infected with Simian Immunodeficiency Virus (SIV) do not show clinical signs of immunodeficiency. Objective: Therefore, the present study sought to determine whether pathogenicity occurs in new-born AGMs following serial in vivo passage with SIVagm. Methodology: One new-born AGM was inoculated with cell-free SIVagm isolated from plasma of a naturally infected AGM and subsequent bone marrow serial transfusions done to other three AGMs at two weeks intervals. Virus isolation and quantification was determined by limiting dilution co-culture method. Virus presence was detected by antigen capture ELISA and polymerase chain reaction. Seroconversion was determined by antibody ELISA and confirmed by Western blot. Results: Virus isolation and seroconversion confirmed successful SIVagm passage in new-born AGMs. After one year, all the animals did not show clinical symptoms related to SIVagm infection. Bone marrow transfusions from SIVagm infected new-born into naïve new-borns induced persistent infection and anti-SIV antibody response. However, this did not show presence of disease suggesting that AGMs possess inherent resistance that either kill SIVagm or render immune cells of AGMs non-functional. Conclusion: The results provide valuable information important in investigating the lack of SIV disease pathogenesis in AGMs.