Detection of peripheral HIV-1-specific memory B cells in patients untreated or receiving highly active antiretroviral therapy

Objectives: To examine whether polyclonal activation of circulating B cells, in a process that involves CD40-CD40 ligand and cytokine interactions, could induced HIV-1-specific memory B cells to synthesize HIV-1-specific antibodies. Methods: B cells from 26 HIV-1-infected patients were cultured with a CD40L-transfected cell line plus interleukins 2 and 10 and tested for their secretion of HIV-1 and Toxoplasma gondii-specific antibodies. Results: In vitro activated B lymphocytes from HIV-1-infected patients secreted anti-HIV-1-specific antibodies. B cells from HIV-1-infected patients as well as those from controls chronically infected by T gondii synthesized T gondii-specific antibodies. HIV-1-specific IgG-, IgA- or IgM-secreting B cells represented approximately 1 x 10(-4) to 1 x 10(-5) of total circulating B cells and 1 x 10(-2) to 1 x 10(-3) of immunoglobulin-secreting cells. HIV-1-specific memory B cells were found in 9/9 untreated patients and in 8/17 patients receiving highly active antiretroviral therapy (HAART). The other nine patients showed a normal CD40-CD40L B cell response and six of them produced T gondii-specific antibody B cells. The follow-up of seven patients indicated that HIV-1-specific memory B cells became undetectable after 8 to 46 months of HAART; whereas T gondii-specific memory B cells persisted in parasite coinfected patients. Conclusions: Circulating memory HIV-1-specific B cells were detected in untreated patients and in about half of the patients taking HAART, suggesting that persistent low-level ongoing viral replication is not sufficient to maintain HIV-1-specific memory B cells. (C) 2003 Lippincott Williams Wilkins.