Peptidases from latex of Carica candamarcensis upregulate COX-2 and IL-1 mRNA transcripts against Salmonella enterica ser. Typhimurium-mediated inflammation.

The immunomodulatory properties of a mixture of cysteine peptidases (P1G10) obtained from the fruit lattice of Carica candamarcensis were investigated. P1G10 was obtained from fresh latex samples by chromatography in a Sephadex column and initially administered to Swiss mice (n = 5; 1 or 10 mg/kg) via i.p. After 30 min, the mice were injected with carrageenan (0.5 mg/mouse) or heat-killed S. Typhimurium (10(7) CFU/mL; 100°C/30 min) into the peritoneal cavity. Afterwards, two animal groups were i.p. administered with P1G10 (n = 6; 1, 5, or 10 mg/Kg) or PBS 24 hours prior to challenge with live S. Typhimurium (10(7) CFU/mL). P1G10 stimulated the proliferation of circulating neutrophils and lymphocytes, 6 h after injection of carrageenan or heat-killed bacteria, respectively. Furthermore, survival after infection was dose-dependent and reached 60% of the animal group. On the other hand, control mice died 1-3 days after infection. The examination of mRNA transcripts in liver cells 24 h after infection confirmed fold variation increases of 5.8 and 4.8 times on average for IL-1 and COX-2, respectively, in P1G10 pretreated mice but not for TNF-α, IL-10, γ-IFN and iNOS, for which the results were comparable to untreated animals. These data are discussed in light of previous reports.