CD8+ T-cell Response Potential, as Determined by Expression of the High Affinity Interleukin-2 Receptor, in Murine AIDS
Human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS), which can follow infection with the virus, is a major health issue worldwide. Murine AIDS (MAIDS) is a model system used for the study of AIDS. By comparing the immune response to murine leukemia virus of MAIDS resistant and susceptible strains of mice, and making observations of the features of MAIDS, we can hopefully gain insight into ways of approaching treatment and prevention of HIV and AIDS in humans. Studies have shown that CD8+ T-cells are important for resistance to MAIDS and human AIDS, and it has been proposed that it is the level of CD8+ T-cell activation which is important (Makino et al., 1992; Tang et al., 1997). Interleukin-2 (IL-2) is one of the key cytokines involved in the activation of T-cells. Since CD8+ T-cells require a stronger IL-2 signal than CD4+ T-cells to be activated, they are more likely to be affected by decreases in levels of IL-2. T-cells can express both high and low affinity IL-2 receptors. The low affinity receptor expressed on naïve T-cells is comprised of two subunits, beta and gamma, while the high affinity receptor on activated T-cells is made up of the beta and gamma subunits, along with an alpha subunit (CD25). This study used flow cytometry to compare the number of CD8+ T-cells expressing high affinity IL-2 receptors in MAIDS susceptible and resistant mice. CD8+ T-cells were isolated from the spleen and stained with a fluorescently-labeled antibody specific to the high affinity-specific alpha subunit of the IL-2 receptor (CD25). Results indicate that BALB/c and C57BL/6 mice may have different expression patterns of CD25 on CD8+ T-cells following infection. In addition, the percent of spleen leukocytes expressing CD25 was found to be higher in 2-week infected C57BL/6 mice than in 2-week infected BALB/c mice.