Human Immunodeficiency Virus–Infected Patients Receiving Highly Active Antiretroviral Therapy Maintain Activated CD8⁺T Cell Subsets as a Strong Adaptive Immune Response to Cytomegalovirus

Abstract

CD8(+) T lymphocyte function specific for human cytomegalovirus (CMV) was evaluated in 14 patients infected with human immunodeficiency virus (HIV) receiving highly active antiretroviral therapy (HAART) and 26 CMV-seropositive donors without HIV infection. Fifty-seven percent of the HIV-infected group had CMV-specific cytolytic activity in freshly isolated peripheral blood mononuclear cells (PBMC) against targets expressing CMV pp65. Both interferon (IFN)-gamma secretion by CD8(+) T cells and the frequency of human leukocyte antigen (HLA)-tetramer-positive T cells in HLA-A*0201-positive HIV-infected subjects correlated with CMV-specific cytolysis. In contrast, PBMC from healthy CMV-seropositive donors did not have either measurable CMV-specific cytolysis or secretion of IFN-gamma without in vitro stimulation. The T helper response to CMV antigens was vigorous in healthy CMV-seropositive donors but low in the cohort of HIV-infected patients. Potent CD8(+) cytotoxic T lymphocyte responses to CMV in HIV-infected patients receiving HAART is the converse of what is found in healthy CMV-seropositive subjects and may be the predominant adaptive immune response against CMV in HIV-infected patients.

Preclinical development of an adjuvant-free peptide vaccine with activity against CMV pp65 in HLA transgenic mice

“…1 Results from in vitro stimulation of human peripheral blood leukocytes using the pp65 495-503 peptide (Table 1) confirm that it functions to stimulate CTLp (CTL precursors) as a memory response from individuals with prior CMV exposure. 13,39,47 To test whether the peptide could also stimulate de novo CTLp without prior virus exposure, a Tg HLA A2.1 mouse model was evaluated. 1 A robust CTL response directed at the pp65 495-503 CTL epitope was found in Tg mice that had been coimmunized with the PADRE T H epitope in IFA.…”

“…47 Collection of the supernatants was performed at 2, 24, 72, and 96 hours after IVS. Recombinant IFN-␥ (Pharmingen) was used for the preparation of a standard curve.…”

“…Briefly, HLA-A2 heavy chain and ␤-2-microglobulin (␤ 2 M), cloned in the vector pHN1, were expressed in Escherichia coli XA90 and refolded with the CMV pp65 495-503 CTL epitope. 47 The refolded HLA-A2/␤ 2 M/peptide complexes were biotinylated using the enzyme BirA (Avidity, Denver, CO) and then purified by fast performance liquid chromatography using a Sephacryl S300 gel filtration column, followed by a MonoQ ion exchange column. The purified biotinylated HLA-A2/␤ 2 M/peptide complexes were conjugated to either streptavidin-phycoerythrin (PE; Pharmingen, San Diego, CA) or to streptavidin-allophycocyanin (Molecular Probes, Eugene, OR).…”

“…A number of groups have explored the specificity of the pp65 [495][496][497][498][499][500][501][502][503] epitope in combination with the HLA A2.1 heavy chain modified for tetramer formation as first described by Altman and colleagues. 47,56,57 We investigated whether the same tetramer preparation that worked specifically with human peripheral blood mononuclear cells would be able to distinguish pp65 495-503 -specific T cells from mouse spleen, as was recently shown for a human p53 HLA A2.1 CTL epitope. 58 Three groups of Tg mice were immunized subcutaneously with 50 nmol K25V and a booster of the same composition with either control (non-CpG) or CpG ss-ODN, or alone.…”

Reduced Type 1 and Type 2 Cytokines in Antiviral Memory T Helper Function Among Women Coinfected with HIV and HCV

“…CMV is a ubiquitous member of the herpes virus family, eliciting potent memory responses in asymptomatic but chronically infected individuals (27)(28)(29). Although CMV-specific T helper responses are reduced in HIV infection compared to healthy subjects, the responses are relatively stronger than HIVspecific responses (30)(31)(32). Thus, responses to CMV are useful to monitor anti-viral responses in patients with T cell dysfunction.…”