Distribution of cell-free and cell-associated HIV surrogates in the colon after simulated receptive anal intercourse in men who have sex with men

Nicolette A. Louissaint, Sridhar Nimmagadda, Edward J. Fuchs, Rahul P. Bakshi, Ying Jun Cao, Linda A. Lee, Jeff Goldsmith, Brian S. Caffo, Yong Du, Karen E. King, Frederick A. Menendez, Michael S. Torbenson, Craig W. Hendrix

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Objectives: Describing the distribution and clearance of HIV surrogates within the gastrointestinal tract to inform rectal microbicide development. DESIGN: Radiolabeled simulated HIV-infected semen was administered, imaged, and biopsied to simulate and measure colonic HIV distribution after anal intercourse. Methods: Healthy male subjects with a history of receptive anal intercourse and experience with the use of anal sex toys were recruited to this study. Apheresis isolated leukocytes were collected before simulated intercourse. These autologous leukocytes, radiolabeled with 9.25 MBq 111 Indium-oxine (cell-associated HIV surrogate), and sulfur colloid particles, labeled with 37 MBq 99m Technectium (cell-free HIV surrogate), were mixed in 3 mL autologous seminal plasma. This simulated HIV-infected semen was administered to subjects via an artificial phallus with urethra after 5 minutes of simulated intercourse. Postdosing dual isotope Single photon emission computed tomography coupled with traditional computed tomography (SPECT/CT) images were acquired at 1, 4, 8, and 24 hours. At 5 hours postdosing, colon biopsies were collected, CD4 cells were extracted, and samples analyzed for radioactivity. RESULTS: SPECT/CT images showed similar luminal distribution for both surrogates, with migration limited to the rectosigmoid colon in all subjects. SPECT showed at least 75% overlap in distribution of both surrogates up to 4 hours after dosing. Biopsies indicate that 2.4% of CD4 cells extracted from rectosigmoid colon tissue were exogenously administered. Conclusions: Our HIV surrogates stayed within the rectosigmoid colon for 24 hours. Exogenously dosed autologous lymphocytes and HIV-sized particles migrate to similar locations and associate with the colonic tissue in the lumen.

Original languageEnglish (US)
Pages (from-to)10-17
Number of pages8
JournalJournal of Acquired Immune Deficiency Syndromes
Issue number1
StatePublished - Jan 1 2012


  • HIV
  • anal intercourse
  • pharmacokinetics
  • rectal microbicide
  • sexual transmission

ASJC Scopus subject areas

  • Infectious Diseases
  • Pharmacology (medical)


Dive into the research topics of 'Distribution of cell-free and cell-associated HIV surrogates in the colon after simulated receptive anal intercourse in men who have sex with men'. Together they form a unique fingerprint.

Cite this