The use of live-attenuated viruses as
vaccines has been successful for the control of
viral infections. However, the development of an effective
vaccine against the human immunodeficiency virus (HIV) has proven to be a challenge. HIV infects cells of the immune system and results in a severe immunodeficiency. In addition, the ability of the virus to adapt to immune pressure and the ability to reside in an integrated form in host cells present hurdles for vaccinologists to overcome. A particle-based
vaccine strategy has promise for eliciting high titer, long-lived, immune responses to a diverse number of viral
epitopes from different
HIV antigens. Live-attenuated viruses are effective at generating both cellular and humoral immunity, however, a live-
attenuated vaccine for HIV is problematic. The possibility of a live-
attenuated vaccine to revert to a pathogenic form or recombine with a wild-type or defective virus in an infected individual is a drawback to this approach. Therefore, these
vaccines are currently only being tested in non-human primate models. Live-
attenuated vaccines are effective in stimulating immunity, however challenged animals rarely clear
viral infection and the degree of attenuation directly correlates with the protection of animals from disease. Another particle-based
vaccine approach for HIV involves the use of virus-like particles (VLPs). VLPs mimic the viral particle without causing an immunodeficiency disease. HIV-like particles (HIV-LP) are defined as self-assembling, non-replicating, nonpathogenic, genomeless particles that are similar in size and conformation to intact virions. A variety of VLPs for both HIV and SIV are currently in pre-clinical and clinical trials. This review focuses on the current knowledge regarding the immunogenicity and safety of particle-based
vaccine strategies for HIV-1.