Cytotoxic Activity and Memory T Cell Subset Distribution of in vitro-Stimulated CD8+ T Cells Specific for HER2/neu Epitopes

Abstract

Minimal residual disease remaining after resection of primary tumors can lead to tumor recurrence and metastasis, increasing mortality and morbidity rates among cancer patients. Thus, there is a need for new technologies for recognition and elimination of single cancer cells remaining in a patient's body after radiation therapy, chemotherapy, or surgical resection. Effector CD8 + T cells, also commonly known as cytotoxic T lymphocytes (CTLs), play a key role in antitumor cellular immunity and, when properly activated, are able to effectively destroy tumor cells. The aims of this study were to obtain CD8 + CTLs specific for the HER2/neu epitopes E75 and E88 and to assess the cytotoxic activity and composition of these cells in terms of the distribution of memory T-cell subsets. We obtained HER2-specific CD8 + T cells and assessed T cell subset distribution among them including naive T cells (T N ), central memory T cells (T CM ), effector memory T cells (T EM ), stem cell-like memory T cells (T SCM ) and terminally-differentiated T cells (T EMRA ) via eight-color flow cytometry. HER2-specific CTLs were largely (~40–50%) represented by T SCM cells, a population capable of mounting pronounced antitumor immune responses due to a combination of effector function and self-maintenance. In comparison with activated peripheral blood mononuclear cells (PBMCs) and bulk CD8 + T cells, HER2-specific CTLs exhibited greater cytotoxicity against the HER2-expressing human breast adenocarcinoma cell line MCF-7 and produced higher levels of IFN-γ in response to tumor cells. We also showed the presence of HER2-specific CTLs in healthy individuals and increase in them in HER2-positive breast cancer patients. Collectively, our results suggest that HER2-specific CD8 + T cells isolated using this approach could be used for adoptive T-cell transfer to eliminate tumor cells and prevent metastasis and relapse in patients with HER2-overexpressing cancers.

Hesperetin as an adjuvant augments protective anti‐tumour immunity responses in B16F10 melanoma by stimulating cytotoxic CD8+ T cells

“…CD8 + T cells play an essential role in anti‐tumour immunity and can effectively kill tumour cells using CTL function. In addition, CD4 + T cell activity is indispensable for cytotoxicity . We then determined whether hesperetin as an adjuvant enhanced the immune response of CD4 + T lymphocytes.…”

“…In addition, CD4 + T cell activity is indispensable for cytotoxicity. 24 We then determined whether hesperetin as an adjuvant enhanced the immune response of CD4 + T lymphocytes. We stained for cytokines including IL-4 and IFN-γ, and found that, compared to vaccination with inactivated B16F10 antigen alone, inactivated B16F10 antigen plus HES stimulated high levels of cytokine secretion ( Figure 3A).…”

Frequency of CD4+ regulatory T cells, CD8+ T cells, and human papilloma virus infection in Egyptian Women with breast cancer

“…A positive correlation was observed in multiple studies between the number of tumor infiltrating cytotoxic CD8+ T cells and clinical outcome in BC that may improve patient survival. 24,37,46,60,62 Decreased number of tumor infiltrating CD8+ T cells in BC was significantly associated with lymph node metastasis and a higher disease stage. These results suggest that cytotoxic CD8+ T cells are heavily involved in antitumor immune responses.…”

Association of CD4+ CD25+ FOXP3+ regulatory T-cells and human papilloma virus infection in Egyptian Women with breast cancer

“…A positive correlation was observed in multiple studies between the number of tumor infiltrating cytotoxic CD8+ T cells and clinical outcome in BC that may improve patient survival [13,26,36,41].…”