A non-toxic recombinant protein rSUMO-CPBm4 as a potential vaccine candidate against Clostridium perfringens type C beta enterotoxemia

@#Beta toxin (CPB) is a lethal toxin and plays a key role in enterotoxemia of ruminants caused by Clostridium perfringens type C strain. The existing vaccines based on crude CPB need time-consuming detoxification and difficult quality control steps. In this study, we synthesized the rCPBm4 of C. perfringens type C strain and small ubiquitin-like modifier (SUMO)-tag CPBm4 (rSUMO-CPBm4) by introducing four amino acid substitutions: R212E, Y266A, L268G, and W275A. Compared with rCPBm4, rSUMO-CPBm4 was expressed with higher solubility in Escherichia coli BL21 (DE3). Neither rCPBm4 nor rSUMO-CPBm4 was lethal to mice. Although rCPBm4 and rSUMO-CPBm4 were reactogenic with polyclonal antibodies against crude CPB, rabbits vaccinated with rSUMO-CPBm4 developed significant levels of toxin-neutralizing antibody (TNA) titers that conferred protection against crude toxin challenge. These data suggest that genetically detoxified rSUMO-CPBm4 is a promising subunit vaccine candidate for C. perfringens type C beta enterotoxemia.

Clostridium perfringens α and ß recombinant toxoids in equine immunization / Toxóides recombinantes α e ß de Clostridium perfringens na imunização de equinos

Clostridium perfringens is considered one of the main causative agents of superacute enterocolitis, usually fatal in the equine species, due to the action of the ß toxin, and is responsible for causing severe myonecrosis, by the action of the α toxin. The great importance of this agent in the equine economy is due to high mortality and lack of vaccines, which are the main form of prevention, which guarantee the immunization of this animal species. The aim of this study was to evaluate three different concentrations (100, 200 and 400µg) of C. perfringens α and ß recombinant toxoids in equine immunization and to compare with a group vaccinated with a commercial toxoid. The commercial vaccine was not able to stimulate an immune response and the recombinant vaccine was able to induce satisfactory humoral immune response in vaccinated horses, proving to be an alternative prophylactic for C. perfringens infection.(AU)

Clostridium perfringens é considerado um dos principais agentes causadores de enterocolites superagudas, geralmente fatais na espécie equina, devido à ação da toxina ß, além de ser responsável por causar quadros graves de mionecrose, pela ação da toxina α. A grande importância desses agentes na equinocultura, deve-se a elevada mortalidade e a inexistência de vacinas, principal forma de prevenção, que garantam a imunização dessa espécie animal. O objetivo deste trabalho foi avaliar três diferentes concentrações (100, 200 e 400µg) dos toxóides recombinantes α e ß de C. perfringens na imunização de equinos, bem como comparar com um grupo vacinado com um toxóide comercial. A vacina comercial não se mostrou capaz de estimular uma resposta imune e a vacina recombinante foi capaz de induzir resposta imune humoral satisfatória em equinos vacinados, provando ser uma alternativa profilática para infecção por C. Perfringens.(AU)

Effects of beta-toxin of Staphylococcus aureus and Neuraminidase of Streptococcus pneumoniae on Ciliary Activity of Nasal Ciliated Epithelial Cells

BACKGROUND AND OBJECTIVES: The in vitro effects of pneumococcal neuraminidase and staphylococcal beta-toxin on ciliary activity were investigated at different concentrations and lengths of exposure. MATERIALS AND METHODS: The ciliated epithelial cells were taken from the maxillary sinus mucosa of rabbits. Ciliary beat frequency (CBF) was measured at concentrations of 0.01, 0.1 and 1.0 U/mL of neuraminidase and 0.1, 1.0, 2.0, 5.0 and 10 U/mL of beta-toxin using a video-computerized analysis technique. The CBF was measured 2, 4, 6, 12, 24 and 48 hours after administration of the neuraminidase and beta-toxin. In the control group, normal saline was percutaneously applied to the right maxillary sinus. In the experimental group, 2 U/mL of beta- toxin was applied to the left maxillary sinus using the same technique. At 7 days, all of the mucosae were taken from the inferomedial wall of the maxillary sinus for light microscopy. RESULTS: There was no change in CBF during a 48-hour incubation at 0.01, 0.1 and 1.0 U/mL of neuraminidase. However, the CBF dropped significantly after an 8-hour incubation at 2.0 U/mL of beta-toxin (p<0.05, repeated measures ANOVA). No ciliary activity was observed after a 12-hour incubation at 10 U/mL of beta-toxin. The mucoid, purulent discharge was observed in the maxillary sinuses of the experimental group. Prominent epithelial disruption and infiltration of inflammatory cells into the epithelium and lamina propria were observed in the beta-toxin-applied group. CONCLUSION: The results of this study suggest that staphylococcal beta-toxin may reduce ciliary activity and induce sinusitis without occlusion of the natural ostium of the maxillary sinus in rabbits. This study provides another animal model of sinusitis for understanding the pathogenesis of sinusitis caused by bacterial exotoxins.