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A Restriction Enzyme Based Cloning Method to Assess the In vitro Replication Capacity of HIV-1 Subtype C Gag-MJ4 Chimeric Viruses
Published on: August 31, 2014
Vaccine evaluation studies of replication-defective SIVsmB7
E N Kraiselburd1, A Salaman, M Beltrán
1Department of Microbiology and Medical Zoology, School of Medicine, University of Puerto Rico, San Juan 00936, USA.
Cellular and Molecular Biology (Noisy-Le-Grand, France)
|February 4, 1998
Summary
Non-infectious simian immunodeficiency virus (SIV) particles did not prevent infection in macaques. However, one immunization method showed potential for later virus clearance and more stable CD4 counts post-infection.
Area of Science:
- Virology
- Immunology
- Vaccinology
Background:
- Developing effective vaccines against simian immunodeficiency virus (SIV) is crucial for understanding and combating human immunodeficiency virus (HIV).
- Non-infectious virus-like particles (VLPs) expressing SIV env and gag genes, but lacking essential replication genes (pol, vpx/vpr), offer a potential platform for vaccine development.
Purpose of the Study:
- To assess the protective immunity induced by different immunization strategies using SIVsmB7 VLPs against a pathogenic SIVsmE660 challenge in rhesus macaques.
- To evaluate the impact of immunization on viral load, antibody responses, and CD4+ T cell counts following infection.
Main Methods:
- Three groups of rhesus macaques were immunized with SIVsmB7 VLPs using various prime-boost strategies, including cell-associated, cell-free, adjuvant combinations, and iron oxide microbead conjugation.
- Animals were challenged intravenously with a pathogenic SIVsmE660 strain.
- Viral load, antibody titers (ELISA), neutralizing antibodies, and CD4+ T cell counts were monitored post-challenge.
Main Results:
- All immunized animals became infected, indicating a lack of sterilizing immunity.
- Low-titer antibodies and low or undetectable neutralizing antibodies were observed before challenge, with strong anamnestic responses post-challenge.
- Animals immunized with cell-associated SIVsmB7 (Group A) exhibited transient viremia and more stable CD4+ T cell counts compared to other groups and controls.
Conclusions:
- Immunization with SIVsmB7 VLPs did not confer sterilizing immunity against a highly pathogenic SIV strain.
- Cell-associated SIVsmB7 immunization may contribute to delayed viral clearance and immune stabilization during infection.
- Further research into VLP-based SIV vaccines is warranted, focusing on strategies that enhance protective immune responses.
