A toxicological evaluation of a claudin modulator, the C-terminal fragment of Clostridium perfringens enterotoxin, in mice.

Tight junctions (TJs) maintain cellular polarity between the apical and basolateral region of epithelial cells. Claudin, a tetra-transmembrane protein, plays a pivotal role in the barrier function of TJs. We previously found that a claudin modulator, the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), may be a promising candidate for improving the mucosal absorption of drugs. C-CPE is a fragment of enterotoxin, and putative CPE claudin receptors are highly expressed in liver and kidney. The safety and antigenicity of C-CPE must be evaluated for future clinical application. Therefore, we evaluated whether C-CPE administration in mice leads to tissue injury or production of antibodies. Intravenous administration of C-CPE at 5 mg/kg, which is a more than 25-fold higher dose than that used in a murine mucosal absorption model, did not increase biochemical markers of liver and kidney injury even after 11 injections once a week. Nasal C-CPE administration (2 mg/kg) once a week for 11 administrations also did not increase these biochemical markers, but 6 administrations of C-CPE resulted in elevation of C-CPE-specific serum IgG. These results indicate that development of a less antigenic claudin modulator will be essential for future clinical application of a C-CPE-based mucosal absorption enhancer.

Endogenous tumor necrosis factor induction with Bordetella pertussis vaccine as a triggering agent and its therapeutic effect on MM46 carcinoma-bearing mice.

Induction of endogenous tumor necrosis factor (TNF) by administration of Bordetella pertussis vaccine (BPV) as a triggering agent and its therapeutic effect against MM46 carcinoma were investigated in C3H/He mice. Test triggering agents were injected intravenously into mice after intravenous injection of 4-fold dilution of macrophage activating factor (MAF) or 10(4) units of murine interferon-gamma (Mu-IFN-gamma). Then sera were obtained from the mice, and their TNF activities were assayed on L-929 cells by the method of Ruff and Gifford. The triggering activity of BPV was the highest among those of conventional triggers, such as lipopolysaccharide (LPS) of Escherichia coli, and OK-432. The levels of serum TNF activity triggered by BPV (4 X 10(9) cells), LPS of E. coli (3 micrograms) and OK-432 (3 KE) were 5350, 85 and 102 units/ml, respectively. Growth of MM46, a spontaneous mammary carcinoma cell line of C3H/He was observed for 35 days after tumor inoculation and was suppressed significantly by intravenous injection of MAF and BPV (4 X 10(9) cells). On local injection of BPV (2 X 10(9) cells) into murine tumors, complete regression was observed in 67% of the mice tested with or without MAF priming on day 25 after tumor inoculation, and intratumoral TNF activity was observed even in the case of the single injection of BPV.