Sheena Banks, McMurry class of 2006, presented aspects of her graduate research on HIV Mediated CD4+ Cell Depletion. Ms. Banks completed a Master’s degree in Immunology at the University of Texas Medical Branch in Galveston and currently works as a Research Associate at the Texas Tech School of Pharmacy in Abilene, Texas.
An understanding of the retroviral replication process is very important in the successful treatment of HIV. The HIV virus infects a variety of immune cells expressing a surface protein receptor called CD4. These cells are central to the immune system’s mounting a specific response to a variety of infections, and their destruction effectively renders the patient void of a functioning immune system. Many times, treatment appears to be successful for a time, but later AIDS develops as the body is compromised by secondary infections. HIV infected cells persist in the body through a variety of mechanisms–latent periods with a resurgence and rapid mutation rates that render specific immune responses to foreign agents incapable of reining in and defeating an HIV infection.
Sheena worked on a project using mice to find ways to encourage infected cells to “home”, or seek the lymph nodes where they might undergo apoptosis – the natural cell death process used to remove damaged cells from the body. During the course of an HIV infection, CD4 cells migrate from the blood to lymph nodes, where 90-95% are destroyed by infection. The fate of the remaining 5-10% CD4-bearing cells was not known. Her work determined that these cells are actually T-regulatory cells whose role is to slow down the immune response once an infection is over and to recruit CD4 cells to lymph nodes. She found that the presence of T-regulatory cells promoted an environment within the lymph nodes that favored HIV proliferation, rather than apoptosis – normal programmed cell death processes that remove damaged cells from the body. Such a ”sorting out” of the roles and activities of T-regulatory and CD4 cells
during the course of an HIV infection is an important step in finding new strategies for treatments vs. HIV infections, something Sheena says is the goal of HIV researchers right now.
Sheena graciously fielded a great many diverse questions on HIV infections and research, and offered McMurry students opportunities to work in the labs at TTU School of Pharmacy-Abilene – participating in research on cancer, viral infections, developmental biology, and many other ongoing projects guided by TTUSOP faculty.