Chronic HIV-2 infection protects against total CD4+ cell depletion and rapid disease progression induced by SHIV89.6p challenge

Ron A. Otten, Debra R. Adams, Caryn N. Kim, Jennifer K. Pullium, Tamela Sawyer, Eddie Jackson, Thomas M. Folks, Sal Butera

    Research output: Contribution to journalArticlepeer-review

    6 Scopus citations


    Objective: To better understand HIV-1 sexual transmission risk, we have studied the susceptibility of HIV-2-exposed, uninfected (EU) female pig-tailed macaques to intravaginal (IVAG) re-challenge with the homologous HIV-2 strain, followed by heterologous SHIV89.6p. Methods: Nine female macaques, previously protected by a post-exposure prophylaxis (PEP) regimen, along with one mock-treated EU animal, were re-exposed to HIV-2 by the IVAG route approximately 1.5 years later. A single follow-up challenge was performed approximately 1 year later with SHIV89.6p to assess susceptibility of chronic HIV-2-infected animals to further re-infection and pathogenic effects with a heterologous virus, somewhat mimicking HIV-1. Results: Eight of ten macaques (80%) became infected systemically with HIV-2, and plasma or cervicovaginal vRNA levels did not appreciably differ from prior historic non-PEP control macaques. Interestingly, all eight HIV-2-infected females were susceptible to SHIV89.6p infection by either intravenous (n = 4) or IVAG exposure (n = 4) after one inoculation. Plasma vRNA levels in these groups were controlled by week 8 and there were no decrease in CD4+ T cells > 50%. The remaining two HIV-2 EU macaques, inoculated intrarectally with SHlV 89.6p, were unable to control virus replication and succumbed to disease by week 25 or week 61. Conclusions: Our findings demonstrate that successful PEP regimens to prevent an initial infection do not have any lasting protective effects. The observed lack of cross-protection against SHIV 89.6p transmission among chronic HIV-2-infected macaques provides modeling support for limited epidemiologic data indicating that human HIV-2 infection does not protect against HIV-1 infection, but may serve to alter overt clinical outcome.

    Original languageEnglish (US)
    Pages (from-to)1127-1135
    Number of pages9
    Issue number8
    StatePublished - May 21 2004


    • CD4
    • HIV
    • Pig-tailed macaque
    • Re-challenge
    • Simian/human immunodeficiency virus

    ASJC Scopus subject areas

    • Immunology and Allergy
    • Immunology
    • Infectious Diseases


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