Safety and Efficacy of Activated Transfected Killer Cells for Neutropenic Fungal Infections

Abstract

Background Invasive fungal infections cause considerable morbidity and mortality in neutropenic patients. White blood cell transfusions are a promising treatment for such infections, but technical barriers have prevented their widespread use. Methods To recapitulate white blood cell transfusions, we are developing a cell-based immunotherapy using a phagocytic cell line, HL-60. We sought to stably transfect HL-60 cells with a suicide trap (herpes simplex virus thymidine kinase), to enable purging of the cells when desired, and a bioluminescence marker, to track the cells in vivo in mice. Results Transfection was stable despite 20 months of continuous culture or storage in liquid nitrogen. Activation of these transfected cells with retinoic acid and dimethyl sulfamethoxazole enhanced their microbicidal effects. Activated transfected killer (ATAK) cells were completely eliminated after exposure to ganciclovir, confirming function of the suicide trap. ATAK cells improved the survival of neutropenic mice with lethal disseminated candidiasis and inhalational aspergillosis. Bioluminescence and histopathologic analysis confirmed that the cells were purged from surviving mice after ganciclovir treatment. Comprehensive necropsy, histopathology, and metabolomic analysis revealed no toxicity of the cells. Conclusions These results lay the groundwork for continued translational development of this promising, novel technology for the treatment of refractory infections in neutropenic hosts.

Concise Review: Next-Generation Cell Therapies to Prevent Infections in Neutropenic Patients

“…Although neutrophil‐like cell lines are currently available, they originally derive from human leukemic samples, which may hamper safe clinical use. Lin et al have shown that HL‐60‐differentiated neutrophil‐like cells, named ATAK, improve overall outcome in a chemotherapy‐treated neutropenic mouse model challenged with Candida albicans and Aspergillus fumigatus [72]. Their effort to engineer a “suicide trap” within these cells points toward the significant safety concern of transplanting immortalized cells into patients.…”

Targeting neutrophils using novel drug delivery systems in chronic respiratory diseases

“…Antifungal therapy failured to manage the infection due to the presence of hyphae, the main feature of the fungus that allows it to penetrate blood vessels, and this prevents the penetration of antifungal agents into the fungus (Mehrad et al, ). Studies conducted have shown that neutrophils display potent anti‐ Aspergillus activity, exhibiting efficient migration to sites of fungal infection (Farowski et al, ; Lin et al, ; Lin, Ibrahim, Baquir, Palosaari, & Spellberg, ; Todeschini et al, ). It has been also found that posaconazole, a broad‐spectrum antifungal, accumulates in large concentrations in leukocytes, especially in neutrophils (Campoli et al, ; Conte Jr. et al, ; Hof, ).…”

It takes a village: Phagocytes play a central role in fungal immunity

“…A variety of animal models demonstrate efficient neutrophil chemotaxis with rapid extravasation to the site of fungal infections. [48][49][50][51] To correct deep neutropenia multiple trials using granulocyte transfusions have been attempted. Despite these efforts, the results have been largely disappointing without a clear signal of protection.…”