C. perfringens toxinotype B is the etiologic agent of dysentery in newborn lambs and haemorrhagic enteritis and enterotoxemia in goats, calves and foals [2] and [3]. More recently, toxinotype B has been detected in a human with a clinical presentation of multiple sclerosis, providing clues for environment triggers of the disease [4]. C. perfringens toxinotype D affects mainly sheep and lambs but also causes infections in goats and calves [2] and [3]. The most important factor in initiating disease is the disruption of the microbial

balance in the gut due to overeating carbohydrate rich food, which causes proliferation of C. FK228 ic50 perfringens and consequent overproduction of the toxin [2] and [5]. Overproduction of Etx causes increased intestinal permeability, facilitating entry of the toxin into the bloodstream and its spread into various organs, including the brain, lungs and kidneys. While infection of the central nervous system results in neurological disorders, the fatal effects on the organs often lead to sudden

death [6] and [7]. For full activity of the toxin, proteolytic processing is required, with carboxy-terminal and amino-terminal peptides removed. Toxin activation typically occurs in the gut either by digestive proteases GPCR Compound Library high throughput of the host, such as trypsin and chymotrypsin [8], or by λ-protease produced by C. perfringens itself [9] and [10]. To prevent Etx-induced enterotoxemia in domesticated livestock, a number of commercial vaccines are available that have been used extensively over the past decades. These vaccines are based on either formaldehyde treated C. perfringens type D culture filtrate or formaldehyde-inactivated recombinant wild type toxin [11] and [12]. These vaccine preparations have several disadvantages: (1) complete removal of free formaldehyde is required to avoid possible toxic side effects, (2) toxoiding using formaldehyde can

show considerable batch to batch variation in immunogenicity of these vaccines [12], (3) inflammatory responses following vaccination can lead to reduced feed consumption [13] and (4) reversion Liothyronine Sodium to toxicity may occur in incompletely inactivated bacterial toxins. Therefore, there is a need to identify Etx variants with reduced toxicity relative to wild type toxin. One approach to solving this problem is to develop recombinant vaccines based on site-directed mutants with markedly reduced toxicity. Amino acid residues Y30 and Y196 have previously been identified to play key roles in cell binding and thus, cytotoxicity of Etx [14] and [15]. Therefore, this study aimed to determine the potential of a site-directed mutant of Etx with mutations Y30A and Y196A combined, termed Y30A-Y196A, to be exploited as a recombinant vaccine against enterotoxemia. The gene encoding epsilon prototoxin, etxD, from C.