Development and Evaluation of an Ovine Antibody-Based Platform for Treatment of Clostridium difficile Infection

Abstract

Treatment of Clostridium difficile is a major problem as a hospital-associated infection which can cause severe, recurrent diarrhea. The currently available antibiotics are not effective in all cases and alternative treatments are required. In the present study, an ovine antibody-based platform for passive immunotherapy of C. difficile infection is described. Antibodies with high toxin-neutralizing titers were generated against C. difficile toxins A and B and were shown to neutralize three sequence variants of these toxins (toxinotypes) which are prevalent in human C. difficile infection. Passive immunization of hamsters with a mixture of toxin A and B antibodies protected them from a challenge with C. difficile spores in a dose-dependent manner. Antibodies to both toxins A and B were required for protection. The administration of toxin A and B antibodies up to 24 h postchallenge was found to reduce significantly the onset of C. difficile infection compared to nonimmunized controls. Protection from infection was also demonstrated with key disease isolates (ribotypes 027 and 078), which are members of the hypervirulent C. difficile clade. The ribotype 027 and 078 strains also have the capacity to produce an active binary toxin and these data suggest that neutralization of this toxin is unnecessary for the management of infection induced by these strains. In summary, the data suggest that ovine toxin A and B antibodies may be effective in the treatment of C. difficile infection; their potential use for the management of severe, fulminant cases is discussed.

A Mixture of Functionally Oligoclonal Humanized Monoclonal Antibodies That Neutralize Clostridium difficile TcdA and TcdB with High Levels ofIn VitroPotency ShowsIn VivoProtection in a Hamster Infection Model

“…Although animals immunized with peptides produced high serum titers (typically 1:100,000), neutralizing antibodies could not be isolated. Animals which had been crosstoxin immunized and screened produced a small number of crossreactive MAbs, none of which demonstrated neutralizing activity, consistent with previous observations (34,41). Together with the results of analysis of sequence alignments, these data suggested that it was not possible to identify MAbs which potently neutralized both TcdA and TcdB.…”

“…Parenteral administration of purified antibodies offers control over both timing and dose. The manufacture of colostrum or serum polyclonal antibodies from cow, sheep, chicken, and alpaca or other species for therapeutic use can have production quality difficulties in controlling the variability of batch-to-batch antitoxin activities (titer and specificity) and the total production capacity, and there can be immunogenicity concerns (24,25,(30)(31)(32)(33)(34). The use of mixtures of monoclonal antibodies offers an advantage over polyclonal sera in these respects.…”

Clostridium difficilevirulence factors: Insights into an anaerobic spore-forming pathogen

“…Passive immunization strategies have focused on the use of toxin-specific antibodies, including humanised monoclonal antibodies, 45 alpaca 41 and ovine-derived antibodies, 46 as well as bovine hyperimmune colostrum. 47 In addition, a number of active vaccination strategies targeting the toxins are under development.…”

Detailed methodological recommendations for the treatment of Clostridium difficile-associated diarrhea with faecal transplantation

“…Ha a fenti tények még nem lennének elegendőek a jelenlegi klinikai gyakorlat globális átértékeléséhez, további fenyegetést jelent, hogy a CDiff fertőzések kezelésére egyre gyakrabban alkalmazott vancomycin per os használta vancomycin-rezisztens Enterococcus (VRE) megjelenésével és ezen törzsekből transconjugatióval, a már hazánkban is leírt, vancomycin-methicillin-rezisztens Staphylococcus aureus (VMRSA) kialakulásával fenyeget [6,7,8]. Nem meglepő, hogy világszerte történnek próbálkozások alternatív kezelési, megelőzési és infekció kontroll stratégiák kidolgozására [9,10,11,12,13]. Ezen alternatív eljárások közül egyelőre egyedül a széklettranszplantáció vagy más néven faecalis bacteriotherápia kezd nemzetközileg elterjedni, elsősorban a beavatkozással elérhető kiváló gyógyulási ráta (≈92%) és alacsony recidíva arány (≈6%), másodsorban pedig relatív egyszerűsége, biztonságossága és költséghatékonysága miatt [14,15].…”