Glycoprotein G deletion mutants of equine herpesvirus 1 (EHV1; equine abortion virus) and EHV4 (equine rhinopneumonitis virus).

This research focuses on the creation and examination of Glycoprotein G deletion mutants for equine herpesvirus 1 (EHV1) and 4 (EHV4), and suggests that these mutations could potentially serve as vaccines for these viruses in horses.

Construction of Deletion Mutants

• The study details the development of Glycoprotein G (gG) deletion mutants for two equine herpesviruses – EHV1 and EHV4.
• These “edited” viruses are referred to as EHV1DeltagG and EHV4DeltagG.
• The growth characteristics of these mutants were compared with the parent viruses, with the aim of determining any differences in proliferation and morphology due to the deletion.

Growth Characteristics and Mutations

• It was found that the growth characteristics of EHV1DeltagG were similar to the original EHV1 virus, indicating that the gG deletion did not significantly alter its growth.
• In contrast, all EHV4DeltagG mutants grew at a slower rate in cell culture and exhibited different morphological characteristics, such as smaller plaque sizes.
• Upon further investigation, it was discovered that in addition to the gG deletion, the EHV4DeltagG mutants also had unexpected deletions in the adjacent downstream gene, ORF 71.

Antibodies and Potential Vaccines

• Antibodies produced in response to the mutant viruses were able to neutralize both the mutant and parent viruses. This could suggest potential use of these mutants as vaccines.
• The antisera, or blood serum containing these antibodies, could also be distinguished from antisera to the wild type viruses, particularly using a gG antibody detection ELISA (enzyme-linked immunosorbent assay).
• This ability to distinctly identify gG-deletion mutants from wild type viruses could also make these mutants useful as a marker to differentiate vaccinated horses from those that are naturally infected.