Combination immunotherapy with Survivin and luteinizing hormone-releasing hormone fusion protein in murine breast cancer model

Figure 1 4T-1 breast tumor volume in mice injected with phosphate buffer saline buffer (circle), 20 µg Survivin + Mycobacterium indicus pranii (square) and 50 µg Survivin + Mycobacterium indicus pranii (triangle) at different time points after tumor was palpable.

Figure 2 Interferon-gamma levels measured in mice immunized with 20 µg Survivin (+ Mycobacterium indicus pranii) and 50 µg Survivin (+ Mycobacterium indicus pranii) in comparison to phosphate buffer saline administered control mice and Mycobacterium indicus pranii administered mice. Interferon-gamma is expressed as fold change relative to the levels obtained in phosphate buffer saline administered mice before the tumor challenge. MIP: Mycobacterium indicus pranii.

Figure 3 4T-1 Breast tumor volume in mice immunized with PBS buffer, 20 µg Survivin + Mycobacterium indicus pranii, 20 µg luteinizing hormone-releasing hormone + Mycobacterium indicus pranii and combination of 20 µg Survivin and 20 µg luteinizing hormone-releasing hormone along with Mycobacterium indicus pranii. Tumor volume is measured at different time points from day 19^th when tumor was palpable. LHRH: Luteinizing hormone-releasing hormone.

Figure 4 Graph representing the comparative level of total IgG antibody measured in mice immunized with Survivin (+ Mycobacterium indicus pranii), LHRH(6leu)LTB (+ Mycobacterium indicus pranii) and combination of Survivin and LHRH(6leu)-LTB (+ Mycobacterium indicus pranii). The serum was collected pre tumor challenge (Day -7), on tumor challenge (Day 0) and at the end of the study (Day 38). The total IgG titer was determined against respective antigens in each group. Groups of mice receiving Survivin alone and combination were checked for anti-Survivin antibody titers. Similarly, anti-LHRH titres were checked in mice in groups corresponding to LHRH(6leu)-LTB alone and combination. LHRH: Luteinizing hormone-releasing hormone.

Figure 5 Schematic representation of the study of anti-tumor effect of Survivin, luteinizing hormone-releasing hormone fusion protein individually and in combination. The study was conducted on four groups of mice: Untreated or control, Survivin alone, LHRH(6leu)LTB alone and Survivin + LHRH(6leu)LTB. Individual recombinant proteins were purified and used as immunogen along with Mycobacterium indicus pranii as an immunomodulator in murine model. The mice from all the groups were further challenged with tumor cells, 4T1 and tumor development was observed in each group. LHRH fusion protein was not effective in suppressing tumor alone. However, the combination of both Survivin and LHRH(6leu)LTB inhibited tumor growth substantially followed by Survivin alone. LHRH: Luteinizing hormone-releasing hormone.