Assessment of rSodC, rPknG, rNanH, and rSpaC as Antigens for Diagnostic Tools Against Caseous Lymphadenitis.

Corynebacterium pseudotuberculosis is a bacillus that causes caseous lymphadenitis in small ruminants, leading to great losses to rural producers; thus, an efficient diagnosis is necessary for using disease control measures. This study aimed to evaluate the antigenic potential of four C. pseudotuberculosis recombinant proteins (rSodC, rPknG, rNanH, and rSpaC) against sera of goat and sheep experimentally infected with one of three different C. pseudotuberculosis strains. Goats were infected with CAP76 or CAP21 strain (n = 10), sheep with VD57 strain (n = 6), and a group of not-infected animals (goats and sheep) were kept as a healthy control (healthy n = 12). Sera were collected at 0, 14, 60, 90, 180, or 190 days after inoculation for antigenicity testing using Western blotting and enzyme-linked immunosorbent assay (ELISA) techniques. Cross-reactivity tests with recombinant proteins were performed in goat serum experimentally vaccinated with Nocardia sp. or Rhodococcus equi bacterin. The rSodC protein showed discriminatory antigenic reactivity with a statistically significant difference against three different C. pseudotuberculosis strains evaluated in goats and sheep samples, while rPknG showed statistical significance only against two C. pseudotuberculosis strains evaluated in goats. rSodC was proved to be a strong candidate as a tool for diagnosis of C. pseudotuberculosis infection, once it was able to recognize antibodies against all strains evaluated in goats and sheep.

Analysis of Gtpases Rab 5 and Rab 7 expression from macrophages infected with biofilm-producing and non biofilm-producing strains of Corynebacterium pseudotuberculosis.

Corynebacterium pseudotuberculosis is a facultative intracellular pathogen that uses various mechanisms to survive within macrophages. In phagocytosis, this survival can be attributed to the ability to inhibit phagosome-lysosome fusion. In this fusion, some proteins, including Rabs GTPases, are involved in the maturation process and are responsible for regulating membrane vesicle trafficking. Thus, to better understand these mechanisms, the capacity of biofilm-producing and non biofilm-producing strains of Corynebacterium pseudotuberculosis for modulating the expression of endosomal proteins GTPases Rab 5 and Rab 7 was evaluated in an in vitro study of infection of goat macrophages. Blood was collected from ten Canindé goats, infected with biofilm-producing and non biofilm-producing strains of C. pseudotuberculosis. Blood cells were separated in colloidal silica-polyvinylpyrrolidone gradients (GE Healthcare®). These cells were maintained at 37 °C, with 5% of CO2. After differentiation, macrophages were infected with the mentioned strains. The bacterial pellets were marked with Rab 5 and Rab 7 antibodies, and their expression was observed by flow cytometry. Both strains of C. pseudotuberculosis (biofilm-producing and non biofilm-producing) were observed to be capable of altering the expression of Rab proteins in macrophages cultivated in vitro. Macrophages from the animals infected with the biofilm-producing strain had an increase in the expression of Rab 5 protein, mainly when these macrophages were treated with the non biofilm-producing strain. The same mechanism was shown to function with Rab 7 protein, however at a lower intensity of expression when compared with Rab 5.