Lewis Honors College Capstone Collection

Year of Publication



Arts and Sciences


Veterinary Science

Degree Name

Bachelor of Science in Biology

First Capstone/Thesis Advisor

Dr. David Horohov


The equine infectious anemia virus (EIAV) is closely related to HIV and has been used as a model to identify protective mechanisms against lentivirus infection. In horses, EIA infection progresses for about a year before infected horses manage to control virus replication. This naturally-gained protection is absolutely dependent on active immune responses as evidenced by the fact that immunosuppressive drugs can induce the recurrence of disease. As the resolution of initial viremia correlates with the appearance of virus specific cytotoxic T lymphocytes (CTL), we believe that cellular immune responses play a key role in controlling EIAV in the horse. In a previous study, a modified live EIAV stain (D9) provided effective protection against homologous virus challenge without causing disease, but this vaccine could not achieve optimum protective immunity until six months post vaccination. In this study, development of cell-mediated immunity was monitored in EIAVD9 infected ponies over a six-month period. We hypothesized that both Th1 cytokines and CTL would be upregulated in EIAVD9 infected ponies. To test this hypothesis, ponies were inoculated with the attenuated EIAVD9 strain. Whole blood samples were collected into PAXgene™ tubes weekly during the acute infection stage (first 6 weeks) and at monthly intervals thereafter corresponding to the chronic infection phase. Total RNA was isolated from the PAXgene™ tubes and gene expression for both Th1 cytokine (IFN) and CTL markers (Granzyme B and Perforin) were determined using real-time PCR. At the same time, another group of ponies receiving a virulent EIAV were monitored and sampled as comparison. We found that Th1 cytokine (IFN) and CTL marker (perforin) genes were significantly increased four months post EIAVD9 infection. These results indicate that the maturation of cellular immune response in EIAVD9 infected horses requires at least four months.