Interleukin-2 potentiates foot-and-mouth disease vaccinal immune responses in mice

The present study describes the role of recombinant human interleukin-2 (rh IL-2) as immunomodulatory molecule in foot-and-mouth disease (FMD) vaccinal immune response in a murine model. The humoral immune response was evaluated by examining the antibody titre against FMD virus type O, A22 and Asia 1 in serum samples obtained from different groups of mice inoculated with PBS, FMD vaccine alone; vaccine along with rh IL-2 on 0, 7, 14, 21, and 30 days post vaccination (DPV) by indirect double antibody Sandwich ELISA. The cellular immune response was also examined on different DPV by an MTT based lymphoproliferation assay in splenic mononuclear cells (SMNC) obtained from different groups. IL-2 was able to enhance the specific immune response against FMD virus type O, A22 and Asia 1 as evident by significantly higher ELISA antibody titres (P < 0.05) in serum obtained from mice receiving IL-2 along with vaccine as compared to mice immunized with vaccine alone. Similarly, the same group of mice showed significantly higher lymphoproliferative responses in SMNC against mitogen PHA and FMD virus types O, A22 and Asia 1 on all DPVs as compared to the group inoculated with vaccine alone.