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.
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