Lymphocyte apoptosis: induction by gene transfer techniques

Area of Science:

• Immunology
• Molecular Biology
• Gene Therapy

Background:

• Efficient gene transfer into lymphocytes is a significant challenge.
• The molecular mechanisms underlying lymphocyte resistance to gene transfer are not fully understood.
• Apoptosis (programmed cell death) is hypothesized to contribute to this resistance.

Purpose of the Study:

• To investigate the role of apoptosis in lymphocyte gene transfer resistance.
• To examine the correlation between gene transfer methods, tumor necrosis factor (TNF) secretion, and lymphocyte apoptosis.
• To evaluate the potential of blocking TNF to improve gene transfer outcomes.

Main Methods:

• Lymphocytes were transfected using various nonviral and viral gene transfer methods.
• Apoptosis, necrosis, and TNF-alpha secretion levels were measured in transfected lymphocytes.
• The effect of anti-TNF antibodies on apoptosis and lymphocyte proliferation was assessed.

Main Results:

• Nonviral gene transfer methods, particularly receptor-mediated gene transfer and lipofection, induced significant apoptosis and TNF-alpha secretion in lymphocytes.
• Electroporation and retroviral gene transfer resulted in lower TNF-alpha secretion.
• Blocking TNF-alpha with an antibody significantly reduced apoptosis and necrosis, leading to increased proliferation of lymphocytes engineered with cytokine genes (interleukin-2 or interleukin-7).

Conclusions:

• Gene transfer into lymphocytes triggers TNF-alpha secretion, leading to apoptosis and necrosis.
• Targeting the TNF-alpha pathway can mitigate cell death during lymphocyte gene transfer.
• Blocking apoptosis enhances the viability and proliferation of gene-modified lymphocytes, with implications for their use in cancer gene therapy.