A membrane-bound form of IL-4 enhances proliferation and antigen presentation of CD40-activated human B cells

Generation of antigen-specific T lymphocytes targeting Wilms tumor 1 using activated B cells

In order to develop a therapeutic target for T cells, it is necessary to amplify T cells and increase activity through antigen-presenting cells (APCs) expressing an intracellular cancer antigen. Although dendritic cells are frequently used as APCs, producing dendritic cells is costly and time-consuming. In addition, as dendritic cells are attached cells, they are not suitable for mass production for use as immune cell therapy. On the other hand, B cells are non-adherent floating cells, and thus can easily be cultured in suspension systems. As such, B cells can be considered as suitable substance cells for the development of immune cell therapeutics.B cells lack the antigen-presenting ability of dendritic cells. Therefore, to use B cells as APCs, we previously reported a technology that can be used which simply and effectively produces anti-viral T cells in vitro by activating B cells with α-galactosylceramide (α-GalCer). To apply this technology to anti-cancer treatment, Wilms tumor 1, the most representative cancer antigen expressed in various cancers, was selected. Wilms tumor 1 (WT1) was used to produce anti-cancer (anti-WT1) T cells using active B cells as APCs, and their respective activities were investigated.

Efficient generation of antigen-specific CTLs by the BAFF-activated human B Lymphocytes as APCs: a novel approach for immunotherapy

Efficient antigen presentation is indispensable for cytotoxic T lymphocyte (CTL)-mediated immunotherapy. B-lymphocytes propagated with CD40L have been developed as antigen-presenting cells (APCs), but this capacity needs further optimization. Here, we aimed to expand human B-lymphocytes on a large scale while maintaining their antigen-presenting ability by using both CD40L and B-cell activating factor (BAFF). The addition of BAFF enhanced the expansion efficiency and prolonged the culture time without causing apoptosis of the expanded B-cells. This method thus provided an almost unlimited source of cellular adjuvant to achieve sufficient expansion of CTLs in cases where several rounds of stimulation are required. We also showed that the addition of BAFF significantly enhanced the expression of major costimulatory molecules, CD80 and CD86. Subsequently, the antigen-presenting ability of the B-lymphocytes also increased. Consequently, these B-lymphocytes showed robust CTL responses to inhibit tumor growth after tumor-specific peptide pulses. A similar method induced potent antigen-specific CTL responses, which effectively eradicated human immunodeficiency virus type 1 (HIV-1) latency in CD4 T-lymphocytes isolated from patients receiving suppressive anti-retroviral therapy (ART). Together, our findings indicate that potent antigen-specific CTLs can be generated using BAFF-activated B-lymphocytes as APCs ex vivo. This approach can be applied for CTL-mediated immunotherapy in patients with cancers or chronic viral infections.

Generation of antigen-specific cytotoxic T lymphocytes with activated B cells

BACKGROUND AIMS

Dendritic cells are well known as the most potent antigen-presenting cells. Nonetheless, their use in immunotherapy has been limited by the time-consuming and laborious steps involved in their generation in vitro. Therefore, much attention has been placed on alternative antigen-presenting cells that are relatively more convenient to manipulate.

METHODS

In this study, the efficacy of B cells as antigen-presenting cells, compared with dendritic cells, in the induction of cytotoxic T lymphocytes against cytomegalovirus-specific antigens was evaluated. B cells were isolated from the peripheral blood mononuclear cells of healthy individuals, loaded with α-galactosylceramide for activation, and nucleofected with cytomegalovirus-antigen coding plasmid DNA. Antigen-nucleofected B cells or dendritic cells were cocultured with T cells for 14 days in vitro.

RESULTS

The proliferation of cytotoxic T lymphocytes induced by B cells was similar to that of those induced by dendritic cells. Additionally, the immunogenicity of both sets of cytotoxic T lymphocytes was similar not only in interferon-γ enzyme-linked immunospot assays but also in cytotoxicity assays.

DISCUSSION

These observations suggest that α-galactosylceramide-loaded B cells could be used as antigen-presenting cells as an alternative to dendritic cells. Using B cells has several benefits, including cost-effectiveness and being both less time-consuming and less labor-intensive.

Augmentation of antibody responses by retinoic acid and costimulatory molecules

Antibody production is crucial for a successful vaccine response. Beyond the ability of vitamin A (VA) and its active metabolite, all-trans-retinoic acid (RA) to restore growth in VA-deficient animals, supplementation with VA and/or treatment with RA can augment antibody responses in both VA-deficient and VA-adequate animals. RA alone, and in combination with stimuli that are ligands for the Toll-like receptor family, can augment the adaptive immune response leading to a heightened primary antibody response, and a stronger recall response upon restimulation. Mechanisms may include regulation of cell populations, type 1/type 2 cytokines, and B cell-related transcription factors, leading to accelerated B cell maturation.