Minimal interferon induction in dogs, using a modified polyriboinosinic-polyribocytidylic acid complex

Area of Science:

• Veterinary Immunology
• Interferon Induction
• Canine Research

Background:

• Interferon (IF) plays a crucial role in antiviral defense.
• The ability of canines to produce interferon in response to specific inducers is not fully understood.
• Poly I:C with poly-L-lysine and carboxymethylcellulose (PICLC) is a known interferon inducer in many species.

Purpose of the Study:

• To investigate the efficacy of PICLC and Newcastle disease virus (NDV) as interferon inducers in adult Beagles.
• To determine if canine cell lines exhibit differential sensitivity to interferon induction.
• To assess the potential of Beagles as a model for interferon research.

Main Methods:

• Adult Beagles were intravenously (IV) or intrathecally injected with varying doses of PICLC.
• Beagles were also injected with a high dose of NDV.
• Primary neonatal dog lung and kidney cell cultures, along with the Madin-Darby canine kidney cell line, were treated with PICLC in vitro.
• Cell cultures were assessed for interferon-induced protection against vesicular stomatitis virus (VSV).

Main Results:

• High doses of PICLC were toxic to Beagles, with one fatality at 1 mg/kg, and induced interferon in only two dogs.
• Lower doses of PICLC were less toxic but also less effective in inducing interferon.
• A high dose of NDV failed to induce interferon in Beagles.
• In vitro studies showed no interferon induction in primary dog cell cultures treated with PICLC.
• The Madin-Darby canine kidney cell line demonstrated normal sensitivity to interferon-induced protection.

Conclusions:

• Adult Beagles exhibit a poor response to interferon induction via both PICLC and NDV.
• The lack of interferon response in Beagles is not solely due to the sensitivity of their cell lines.
• Beagles may not be a suitable model for studies requiring robust interferon induction.