In vivo effect of three fractions of Larrea divaricata Cav. (jarilla) on the innate immune system: macrophage response against Candida albicans

Larrea divaricata Cav. (jarilla) is a plant with well-documented applications in folk medicine in Argentina. In this study, we aimed to evaluate functional parameters of peritoneal macrophages isolated from mice injected with three fractions (F1, F2 and F3) of L. divaricata. The response of macrophages against Candida albicans was evaluated. Cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test, apoptosis was evaluated using Giemsa, acridine orange/ethidium bromide and ladder assay, oxidative burst was assayed using nitroblue tetrazolium test and nitrite production using Griess assay. Cell stimulation and their ability to kill C. albicans in vitro were measured. The number and cell viability were similar to controls. However, we found that F1 induces pre-activation of macrophages, and this pre-activation is enhanced by C. albicans. The effects exerted by F1 make it more important than F2 and F3 for the treatment of disseminated candidiasis in patients with immunodeficiency diseases such as AIDS and chronic granulomatous disease, among others.

In vitro immunomodulatory effects of fractions obtained from aqueous extracts of Larrea divaricata Cav (Jarilla) on mouse peritoneal macrophages

BACKGROUND AND AIM

Larrea divaricata Cav. (Zygophyllaceae) is a plant widely used in Argentina.

MATERIAL AND METHODS

We isolated different fractions of L. divaricata aqueous extract containing minor amounts of NDGA, and we analyzed these fractions on mouse macrophages.

RESULTS

We showed that a fraction without NDGA was capableof activating macrophages, principally through the production of mitochondrial anion superoxide and H(2)O(2). This could be important in the defense of infections. Moreover, this fraction decreased NO level suggesting an anti-inflammatory action.

CONCLUSION

These results indicate that NDGA was not the compound responsible for the immunomodulatory action exerted by the aqueous extract from L. divaricata.

Extracellular proteins of Clostridium chauvoei are protective in a mouse model

The anaerobic bacillus Clostridium chauvoei is the causative agent of blackleg, a lethal disease that has an important impact on the sheep and cattle industry worldwide. Immunity to C. chauvoei is considered to be mainly anticellular, and for this reason there is scarce information about the immunogenicity of extracellular proteins. In this work variations in protein profiles, immune response by ELISA and protective capacity of culture supernatants of three C. chauvoei strains, collected at different growth phases, are reported. Sera raised against extracellular antigens also recognised cellular antigens of the same molecular masses. Partially purified cell-free supernatants and those concentrated 10 times by ultrafiltration (C-CFS), obtained at the early stationary phase of growth, induced a strong immunoprotective response, even at low doses, that was more marked for C. chauvoei strain ATCC 10092 (p < or = 0.05). With C-CFS formulations, a clear relationship was observed between IgG titres, protective capacity and concentration of the antigen doses, indicating a specific immune response.

Survival of Yersinia enterocolitica and mesophilic aerobic bacteria on eggshell after washing with hypochlorite and organic acid solutions

Populations of Yersinia enterocolitica 0:9 and mesophilic aerobic bacteria on the shell of fresh chicken eggs were assessed prior and after washing with 0.75%, 1%, and 3% acetic and lactic acids, 50, 100, and 200 mg/liter (ppm) of chlorine, and water. Highest reductions of mesophilic aerobic bacterial populations (normal flora) on trypticase soy agar were 1.28 and 2.15 log10 cycles with 100 and 200 mg/liter of chlorine, 0.28 and 0.36 log10 cycles with 1% and 3% acetic acid, and 0.70 and 0.71 log10 cycles with 1% and 3% lactic acid, respectively, as compared to the control group. No Salmonella or Yersinia were detected among the natural flora of the eggs. On Y. enterocolitica O:9-inoculated eggs, reductions of 2.66, 2.77, and 2.92 log10 cycles by 50, 100, and 200 mg/liter of chlorine, of 2.47, 2.48, and 2.49 log10 cycles by 0.75%, 1%, and 3% of acetic acid, and of 2.48 and 2.72 log10 cycles with 1% and 3% of lactic acid, respectively, were observed with respect to the control. Organic acids at 3% caused detachment of the surface cuticle of the eggshell. Y. enterocolitica was more sensitive to the wash treatments than the natural microflora. The absence of potentially pathogenic Y. enterocolitica, observed for other fresh foods, should be a norm for fresh eggs sold in retail stores.

Alpha-Toxin Production byClostridium septicumat Different Culture Conditions

Clostridium septicum is responsible for a number of diseases, the most serious of which are a frequently fatal non-traumatic gas gangrene in man and braxy malignant oedema and blackquarter in farm animals. Immunity to these diseases is mediated mainly by antitoxin raised against C. septicum alpha toxin, which has hemolytic, lethal and necrotizing activities. Clostridium septicum produces lethal antigen only in low titre and in a variable way. In addition, the immunogenicity of native toxic filtrates is weak, which results in poor antibody response in animals. The aim of this work was to determine the best culture conditions for obtention of the protective antigen. To do this, the presence of the alpha toxin was identified in culture filtrates by means of SDS-polyacrylamide gel electrophoresis (SDS-PAGE) under different culture conditions. The strain used was C. septicum 3606. The cultures were performed in anaerobic conditions at 37 degrees C. Two systems were employed: (a) batch (0.5% initial glucose concentration); and (b) batch with partial feeding of the carbon source (0.1% glucose concentration) at controlled pH. The hemolytic activity of supernatants was determined using human erythrocytes, and the final biomass concentration was estimated by dry weight determination. The proteins present in supernatants were concentrated by ultrafiltration and identified in 10% SDS-polyacrylamide gels. With partial feeding of the carbon source the final biomass (2.22 g/L) was three times higher than the amount reached in batch system (0.70 g/L), however, no difference was found in the hemolytic activity (16 HU50/mL) showing no correlations between cell growth and hemolytic activity of the supernatants. Electrophoresis of filtrate cultures obtained with partial feeding of the carbon source allowed us to identify several bands, two of them corresponded to non-active alpha-protoxin (46 kDa) and the active toxin (42 kDa) and the aggregate of the active toxin at the seeding line. On the other hand, the ultrafiltrate from batch system showed less number of bands and the 46 kDa band was much weaker, suggesting a lower toxin production in this system. It becomes important to determine culture conditions and correlate with extracellular protein presence to optimize C. septicum antigen protector production.