Tilorone hydrochloride: an oral interferon-inducing agent.

Area of Science:

• Immunology
• Pharmacology
• Virology

Background:

• Interferon (IFN) induction is crucial for antiviral defense.
• Synthetic IFN inducers offer therapeutic potential but face challenges.
• Tilorone hydrochloride is a known synthetic IFN inducer.

Purpose of the Study:

• To characterize the unique interferon response induced by tilorone hydrochloride.
• To investigate the mechanisms underlying tilorone's delayed and prolonged IFN induction.
• To assess the role of specific cell populations and host factors in tilorone-mediated IFN production.

Main Methods:

• Administration of tilorone hydrochloride via oral and intraperitoneal routes.
• Measurement of circulating interferon levels over time.
• In vitro studies using mouse lymphocyte and macrophage cultures.
• Experiments involving X-irradiation and antilymphocyte serum (ALS) treatment.
• Assessment of hyporeactivity following repeated tilorone administration.

Main Results:

• Tilorone induced a delayed (12 hr) and prolonged (up to 30 hr) interferon response.
• Oral and intraperitoneal administration yielded similar delayed responses.
• In vitro studies showed no direct induction of interferon by tilorone in lymphocytes or macrophages.
• X-irradiation suppressed interferon production, suggesting a radiosensitive cell source.
• ALS treatment did not significantly alter interferon levels, implicating non-lymphoid cells.
• Repeated tilorone administration led to severe hyporeactivity, more pronounced than with polyinosinic acid:polycytidylic acid.

Conclusions:

• Tilorone hydrochloride elicits a distinct, delayed, and sustained interferon response.
• The primary site of interferon induction appears to be radiosensitive and not lymphocytes.
• Tilorone's capacity to induce profound hyporeactivity presents a significant challenge for its therapeutic application as an interferon inducer.