Determination of cell expansion and surface molecule expression on anti-CD3/28 expanded CD4+ T cells.

CD4+ T cell immunotherapy has potential for treatment in HIV-infected patients. A large number of expanded CD4+ T cells and confirmation of functional-related phenotypes are required for ensuring the successful outcomes of treatment. Freshly isolated CD4+ T cells from healthy donors were activated with anti-CD3/28-coated magnetic beads at different bead-to-cell ratios and cultured in the absence and presence of IL-2 supplementation for 3 weeks. Fold expansion, cell viability, growth kinetic and lymphocyte subset identities were determined. Data demonstrated that a 1:1 bead-to-cell ratio rendered the highest expansion of 1044-fold with 88% viability and 99.5% purity followed by the 2:1 and 0.5:1 ratios. No significant difference in proliferation and phenotypes was found between non-IL-2 and IL-2 supplementation groups. Several specific surface molecule expressions of the expanded cells including chemokine receptors, adhesion molecules, co-stimulatory molecules, activation molecules, maturation markers, cytokine receptors and other molecules were altered when compared to the unexpanded cells. This optimized expansion protocol using the 1:1 bead-to-cell ratio of anti-CD3/28-coated magnetic beads and culture condition without IL-2 supplementation provided the satisfactory yield with good reproducibility. Specific surface molecule expressions of the expanded cells presented potential roles in proliferation, differentiation, homeostasis, apoptosis and organ homing.

A closed-culture system using a GMP-grade culture bag and anti-CD3/28 coated bead stimulation for CD4+ T cell expansion from healthy and HIV-infected donors.

CD4 immunotherapy is potentially useful in immune reconstitution of CD4+ T cells for HIV-infected patients. Transfusion of anti-CD3/28 expanded CD4+ T cells is also proved to be safe and effective in both SIV-infected macaques and HIV-infected patients. However, there is no such standardized and practical protocol available for cell production in order to use in clinics. This study thus aimed to develop a closed-culture system for in vitro CD4+ T lymphocyte expansion by using a commercially available GMP-grade culture bag and anti-CD3/28 activation. Freshly isolated CD4+ T cells by immunorosette formation from healthy donors and cryopreserved CD4+ T cells from HIV-infected patients with CD4 count over 500 cells/µL were stimulated with anti-CD3/28 coated beads. The activated cells were then expanded in conventional culture flasks and GMP-grade culture bags for three weeks. Fold expansion, cell viability, growth kinetic and phenotypic characters were observed. Results revealed that purified CD4+ T cells from healthy individuals cultured in flasks showed better expansion than those cultured in bags (797-fold and 331-fold, respectively), whereas, their cell viability, growth kinetic and expanded CD4+ T cell purity were almost similar. A large-scale production was also conducted and supported consistency of cell proliferation in the closed-culture system. Frozen CD4+ T lymphocytes from the patients were able to remain their growth function and well expanded with a good yield of 415-fold, 85% viability and 96% purity of CD4+ T cells at the end of a 3-week culture in bags. This developed closed-culture system using culture bags and anti-CD3/28 coated beads, therefore, can achieve a large number of expanded CD4+ T lymphocytes with good reproducibility, suggesting a promising protocol required for adoptive immunotherapy.

The Effects of Anti-CD3/CD28 Coated Beads and IL-2 on Expanded T Cell for Immunotherapy.

BACKGROUND: The activation of peripheral blood mononucleated cells (PBMCs) with anti-CD3/CD28-coated magnetic beads promotes intrinsic resistance to HIV as well as cell expansion. OBJECTIVES: The aim of this study was to define an optimal cell isolation protocol for the expansion of PBMCs using anti-CD3/CD28-coated bead stimulation, with the ultimate goal of using these cells for adoptive therapy. MATERIAL AND METHODS: PBMCs were isolated from healthy donor blood samples. To determine the effect of varying the bead-to-cell ratios on the expansion rate and phenotypic characterization of the expanded cells, one million PBMCs were stimulated by anti-CD3/CD28-coated beads at bead-to-cell ratios of 0.1 : 1, 0.5 : 1 and 1.0 : 1 in the presence of 100 U/mL exogenous IL-2; also, one million PBMCs were stimulated by anti-CD3/CD28-coated beads at a bead-to-cell ratio of 0.5 : 1 in the presence of varying concentrations of IL-2 (20, 100 and 1000 U/mL). Cell expansion was carried out for three weeks. The cell numbers, cell viability and phenotypic characterization were determined by trypan blue exclusion and flow cytometry. RESULTS: The initial experiments showed no difference in the expansion rate from cells grown with the three different bead-to-cell ratios. PBMCs can be expanded up to 1000-fold at a 0.5 : 1 bead-to-cell ratio after three weeks of cell expansion with a high viability (90%). Furthermore, in the presence of 100 U/mL IL-2, the percentages of CD3-CD16+CD56+ cells showed marked increases. CONCLUSIONS: The results demonstrate that PBMCs were stimulated with anti-CD3/CD28-coated beads. This method may provide an alternative for driving T cell expansion, which may be very useful in adoptive immunotherapy.

Influence of cell isolation method on the optimization of CD4+ T cell expansion using anti-CD3/CD28 coated beads.

BACKGROUNDS: Activation of CD4+ T lymphocytes with anti-CD3/CD28 coated magnetic beads promotes intrinsic resistance to HIV as well as cell expansion. The propose of this study is to define the optimal cell isolation protocol for expansion of CD4+ T lymphocytes by using anti-CD3/CD28 coated bead stimulation with an ultimate goal of using these cells for adoptive immunotherapy. METHODS: CD4+ T cells were isolated from healthy donor blood samples using three different methods including immunorosette formation, negative selection and CD8 depletion using immunomagnetic beads. These cells were activated with anti-CD3/CD28 coated beads at a bead to cell ratio of 1:1 and cell expansion was carried for 3 weeks. Cell numbers, cell viability and phenotypic characterization were determined by trypan blue exclusion and flow cytometry. RESULTS: Purified CD4+ T lymphocytes which were isolated via immunorosette formation can be expanded up to 1000-fold within 3 weeks with high viability (90%and high purity of CD4+ T lymphocytes (>95%). However, cell expansion from purified CD4+ T lymphocytes which were isolated by negative selection and CD8-depletion provided approximately 300-fold expansion. CONCLUSIONS: The results demonstrate that purified CD4+ T lymphocytes from immunorosette formation provided the highest CD4+ T lymphocyte expansion when stimulated with anti-CD3/CD28 coated beads. This method can be used to obtain a large number of expanded CD4+ T cells for adoptive immunotherapy.

Discordant CD38 measurement of CD8+ T lymphocytes using fluorescein conjugates in comparison with phycoerythrin conjugates.

BACKGROUND: We have previously shown that monitoring of CD38 expression can be used as a marker for antiretroviral drug efficacy in HIV infected patients. However, the detection of CD38 expression may be affected by the sensitivity of the fluorochrome conjugated reagent. OBJECTIVE: In this study, we determined the level of CD38 expression using PE and FITC conjugated anti-CD38 monoclonal antibodies in different groups of HIV infected patients. METHODS: The frequency and mean fluorescence intensity of CD38 expression using PE and FITC conjugated anti-CD38 monoclonal antibodies were detected by flow cytometry either alone or in combination with HLA-DR. A correlation between CD38 expression and CD4 count, the percentage of CD4 or viral load in antiretroviral drug naive HIV infected patients was performed. The results were compared with those for antiretroviral treated HIV infected patients who responsed to therapy and patients with virological failure. RESULTS: We found that while both reagents had the ability to detect a high frequency of CD38 expressing cells in untreated patients, only PE conjugated reagent provided correlation with markers for disease progression. More importantly, FITC conjugated reagent cannot monitor the increase in CD38 expression in patients who showed virological failure. CONCLUSIONS: The results from this study suggest that a cautious selection of fluorochrome conjugated reagents and a method for utilizing the data are extremely critical in the use of CD38 expression as a monitoring tool for ART efficacy.

A new variant cytotoxic T lymphocyte escape mutation in HLA-B27-positive individuals infected with HIV type 1.

The immune response in HIV-infected individuals who carry HLA-B27 is characterized by an immunodominant cytotoxic T lymphocyte (CTL) response to a conserved epitope corresponding to amino acids 263-272 of HIV-1 p24 gag. The arginine at position 264 is a crucial anchor residue. Amino acid substitution at 264 from arginine (R) to glycine (G), lysine (K), or threonine (T) results in a low affinity peptide that binds to HLA-B27 inefficiently and is poorly recognized by T cells that respond to the wild-type peptide. These mutants have been characterized as CTL escape mutations. We studied the plasma virus of 20 HLA-B27 longterm nonprogressors: 14 were wild type and 6 were found to be mutant. Five of these carried known escape mutations coding for K or G at position 264. One patient demonstrated a previously undescribed R264Q mutation in 30/31 clones. This altered epitope failed to elicit an IFN-gamma response from PBMC isolated from any of four HLA-B27-positive individuals with strong responses to wild-type peptide. A peptide binding assay confirmed that the R264Q mutant peptide had 30-fold lower binding affinity to HLA-B27 compared to wild type. Therefore, the R264Q variant is a likely novel escape mutation in HLA-B27-positive individuals.