PART II
Differential anti-tumor effects of three forms
of Tim-3 pathway blocking molecules
Tim-3 is a molecule containing T cell immunoglobulin variable region (IgV)-like domain and mucin-domain, and known to suppress Th-1 immune response. In a previous study, blocking Tim3 pathway increases anti-tumor immunity leading to tumor growth suppression. In this study, I evaluated the tumor suppressive effect of three different molecules blocking Tim3 pathway: Tim3 IgV like domain alone (Tim3V), fusion protein of Tim3V with mouse immunoglobulin CH2CH3 (Tim3VmIg) and its dimer (Tim3VdIg). Both TimVmIg and Tim3VdIg suppress tumor growth but T3V did not. Compared to control Tim3VdIg but not Tim3V reduced frequency of myeloid derived suppressor cells (MDSCs) in splenocytes of mice on 21 day after tumor challenge. These results indicate that Tim3V domain alone is not sufficient for tumor growth suppression but is in the presence of its fusion partner of immunoglobulin CH2CH3.
