Cellular and antibody responses to equine herpesviruses 1 and 4 following vaccination of horses with modified-live and inactivated viruses.

The study compares the effectiveness of two types of vaccines – monovalent and bivalent – in stimulating cellular and antibody responses in horses to two types of equine herpesviruses (EHV-1 and EHV-4). The results revealed that vaccination with a modified live virus can stimulate stronger responses against both viruses compared to an inactivated bivalent vaccine

Research Method

• The study involved comparison of data from lymphocyte blastogenesis tests conducted before and after two vaccinations in healthy horses.
• The tests involved the use of live viruses as antigens. The response of horses given a modified live EHV was measured and compared.
• The presence of Interleukin-2 activity and interferon activity in leukocyte cultures from both groups of vaccines was also checked.
• Lastly, they evaluated the serum antibodies that neutralized EHV-1 infectivity and used an ELISA for EHV-1 and EHV-4 antibodies to check for significant increases in antibodies reactive with these two types of EHV.

Key Findings

• Horses given a modified live EHV-1 vaccine showed significant increases in proliferative responses to EHV-1 and EHV-4.
• While responses to EHV-1 and EHV-4 from horses given the inactivated bivalent vaccine were less, there was no significant difference when comparing post-vaccination lymphocyte blastogenesis tests.
• Neither group showed Interleukin-2 activity; however, interferon activity was found in cultures from both groups of vaccinees, which is an indication of immune response.
• Both vaccines induced significant increases in serum antibodies that neutralized EHV-1 infectivity.
• ELISAs for EHV-1 and EHV-4 antibodies showed that both vaccines induced significant increases in antibodies reactive with EHV-1 and EHV-4. However, the total serum antibody response was significantly higher in horses that received the bivalent inactivated-virus vaccine than in horses that received the monovalent vaccine.

Implications

• The research indicates that the use of a modified live virus as a vaccine can stimulate a stronger cellular and antibody response in horses against EHV-1 and EHV-4 compared to an inactivated virus.
• The study contributes to our understanding of how to effectively combat EHV-1 and EHV-4 in horses.
• Further research could explore the long-term effectiveness and potential trade-offs of using modified live viruses versus inactivated viruses as vaccines for these and other similar conditions.