Immunization against Marek's disease transplantable cell lines

Area of Science:

• Avian Pathology
• Virology
• Immunology

Background:

• Marek's disease (MD) is a significant concern in poultry.
• Lymphoblastoid cell lines, like MDCC-RP1, are used in MD research.
• Understanding cell line behavior is crucial for vaccine development.

Purpose of the Study:

• To evaluate the tumorigenicity and protective potential of passaged MDCC-RP1 cells.
• To compare the efficacy of passaged MDCC-RP1 cells and turkey herpesvirus (HVT) as vaccines against MD.

Main Methods:

• Continuous in vitro passage of MDCC-RP1 cells.
• Inoculation of day-old chicks with varying passaged cell lines.
• Challenge studies with tumorigenic MDCC-RP1 cells and MD virus.
• Vaccination with HVT and assessment of protection.

Main Results:

• High-passaged MDCC-RP1 cells lost tumorigenicity but induced protection against homologous tumor challenge.
• Passaged MDCC-RP1 cells failed to protect against primary MD virus-induced tumors.
• HVT vaccination provided good protection against MD virus and MDCC-RP1 tumors, but less so against MDCC-RP4 cells.

Conclusions:

• Passaged MDCC-RP1 cell lines are unlikely to be effective as field vaccines for Marek's disease.
• HVT remains a viable vaccine candidate, though variations in MD lymphoblastoid cell line response exist.