HIV-specific CD8+ lymphocytes in semen are not associated with reduced HIV shedding

J Immunol. 2005 Oct 1;175(7):4789-96. doi: 10.4049/jimmunol.175.7.4789.

Abstract

Sexual contact with HIV-infected semen is a major driving force behind the global HIV pandemic. Little is known regarding the immune correlates of virus shedding in this compartment, although HIV-1-specific CD8+ T cells are present in semen. We collected blood and semen from 27 chronically HIV-infected, therapy-naive men without common sexually transmitted infections or urethral inflammation and measured HIV-1 RNA viral load and cytokine/chemokine levels in both compartments. HIV-1 RNA levels were 10-fold higher in blood than semen, but discordantly high semen shedding was associated with higher semen levels of the proinflammatory cytokines IL-6, IL-8, IL-12, and IFN-gamma. Virus-specific CD8+ T cell epitopes were mapped in blood by IFN-gamma ELISPOT, using an overlapping HIV-1 clade B peptide matrix, and blood and semen CD8+ T cell responses were then assayed ex vivo using intracellular IFN-gamma staining. HIV-specific CD8+ responses were detected in 70% of semen samples, and their frequency was similar to or higher than blood. There was no correlation between the presence of virus-specific CD8+ T cells in semen and levels of HIV-1 RNA shedding. Among participants with detectable CD8+ IFN-gamma semen responses, their relative frequency was not associated with reduced HIV-1 RNA shedding, and their absolute number was correlated with higher levels of HIV-1 RNA semen shedding (r = 0.6; p = 0.03) and of several proinflammatory cytokines. Neither the presence nor the frequency of semen HIV-specific CD8+ T cell IFN-gamma responses in semen correlated with reduced levels of HIV RNA in semen.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD8-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / virology
  • Cytokines / metabolism
  • Epitopes, T-Lymphocyte / immunology*
  • HIV Infections / blood
  • HIV Infections / immunology*
  • HIV-1 / immunology*
  • Humans
  • Interferon-gamma / metabolism
  • Lactoferrin / metabolism
  • Male
  • Proteinase Inhibitory Proteins, Secretory
  • Proteins / metabolism
  • RNA, Viral / blood
  • Semen / cytology*
  • Semen / immunology
  • Semen / metabolism
  • Semen / virology*
  • Virus Shedding / immunology*

Substances

  • Cytokines
  • Epitopes, T-Lymphocyte
  • Proteinase Inhibitory Proteins, Secretory
  • Proteins
  • RNA, Viral
  • Interferon-gamma
  • Lactoferrin