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Volume 6 Supplement 3

AIDS Vaccine 2009

P04-50 LB. Prevalence of cross-reactive HIV-1 neutralizing activity in HIV-1 infected patients with rapid or slow disease progression


The native envelope gp160 trimer of HIV-1 is thought to shield vulnerable epitopes that could otherwise elicit effectively neutralizing antibodies. However, little is known about the prevalence of naturally occurring cross-reactive neutralizing activity in serum of HIV-1 infected individuals.


Here we studied 35 participants of the Amsterdam Cohort Studies on HIV-1 infection (20 long-term non-progressors (LTNP) and 15 progressors) for the presence of cross-reactive neutralizing activity in their sera at 2 and 4 years after seroconversion (SC). Neutralizing activity was tested in a pseudovirus assay, against a panel of HIV-1 envelope variants from subtype A, B, C, and D.


Already at year 2 post-SC, 7 out of 35 individuals (20%) had cross-reactive neutralizing activity, which increased to 11 individuals (31%) at 4 years post-SC. There was no difference in the prevalence of cross-reactive neutralizing serum activity between LTNP and progressors. Interestingly, high plasma viral RNA load and low CD4+ cell count at set-point were associated with early development of cross-reactive neutralizing activity. Neutralization titers in serum increased during the course of infection for 91% of individuals studied here, albeit less rapidly for those who did not develop cross-reactive neutralizing activity.


Overall, we here demonstrate a relatively high prevalence of cross-reactive neutralizing activity in HIV-1 infected individuals, which increased with duration of infection. These data may imply that immunogenicity of the native envelope spike of HIV-1 for eliciting cross-reactive humoral immune responses may be better than previously anticipated.

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Open Access This article is published under license to BioMed Central Ltd. This is an Open Access article is distributed under the terms of the Creative Commons Attribution 2.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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van Gils, M., Euler, Z., Schweighardt, B. et al. P04-50 LB. Prevalence of cross-reactive HIV-1 neutralizing activity in HIV-1 infected patients with rapid or slow disease progression. Retrovirology 6 (Suppl 3), P390 (2009).

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