Saavedra-Lozano J, Cao Y, Callison J, Sarodi R, Peterson D, Picker L, Ramilo O, Vitetta E; Conference on Retroviruses and Opportunistic Infections (11th : 2004 : San Francisco, Calif.).
Program Abstr Conf Retrovir Oppor Infect 11th 2004 San Franc Calif. 2004 Feb 8-11; 11: abstract no. 427.
Univ. of Texas Southwestern Med. Ctr., Dallas, USA and 2Oregon Hlth. and Sci. Univ., Portland, USA
BACKGROUND: We have previously demonstrated that an anti-CD45RO immunotoxin (IT) kills latently-infected cells obtained from HIV-infected individuals with detectable viremia. In this study, we determined whether this IT could eliminate latently-infected CD4+ T cells from individuals with viremia below the limit of detection (BLD) (<400 copies/mL).METHODS: HIV-infected individuals with viremia BLD were screened for the presence of HIV-infected, replication-competent CD4+ T cells. When such cells could be detected, they were cultured ex vivo with either complete medium (CM) or an anti-CD45RO IT in limiting dilution cultures using 3-5 replicate wells with 5 to 100 x 106 cells per well. Cells were then co-cultured twice with PHA-activated PBMC. From each sample, 30 million cells were also cultured with CM or the IT and analyzed by real-time PCR for the presence of RU5, an HIV cDNA segment corresponding to the initial reverse transcript. This assay can detect 10 copies per 106 cells.RESULTS: We screened 23 HIV-infected individuals. Median time on HAART was 35.5 months (range 5 to 72 months) and with viremia BLD was 29 months (1 to 63 months). Ex vivo treatment of CD4+ T cells with the anti-CD45RO IT reduced the number of RU5 copies by 77% (p = 0.001) from a median (range) of 3676 (17 to 2,515,904) in cells treated with CM vs 206 (5 to 380,202) in cells treated with the IT (p = 0.012). Seven individuals underwent leukopheresis and 5 had detectable HIV-infected, replication-competent cells. The frequencies of HIV-infected T cells in cells cultured in CM vs CM plus the anti-CD45RO IT were 3.2+/-0.80 vs 0.84+/-0.43 per 107 CD4+ cells representing a 74% reduction (p = 0.028), which was comparable to the reductions observed by real-time PCR. Flow cytometric analysis demonstrated that the anti-CD45RO IT eliminated 92% of CD45RO+CD4+ T cells, but that the remaining CD45RA+ CD8+ T cells retained memory responses against CMV antigens.CONCLUSIONS: The anti-CD45RO IT significantly reduced the frequency of HIV latently-infected CD4+ T cells obtained from individuals with viremia BLD. CD8+ memory responses to CMV were substantially maintained after IT treatment. Hence many of these cells are CD45RO-. These results suggest that this IT should be tested for its ability to purge the latent HIV reservoir in vivo.
Publication Types:
Keywords:
- AIDS Vaccines
- Acquired Immunodeficiency Syndrome
- Anti-HIV Agents
- Antigens, CD4
- Antigens, CD45
- Antiretroviral Therapy, Highly Active
- CD4-Positive T-Lymphocytes
- HIV
- HIV Core Protein p24
- HIV Infections
- HIV Protease Inhibitors
- HIV Seropositivity
- Immunotoxins
- T-Lymphocytes
- Viremia
- immunology
Other ID:
UI: 102271389
From Meeting Abstracts