Enhancement of toxin- and virus-neutralizing capacity of single-domain antibody fragments by N-glycosylation

Single-domain antibody fragments (VHHs) have several beneficial properties as compared to conventional antibody fragments. However, their small size complicates their toxin- and virus-neutralizing capacity. We isolated 27 VHHs binding Escherichia coli heat-labile toxin and expressed these in Saccharomyces cerevisiae. The most potent neutralizing VHH (LT109) was N-glycosylated, resulting in a large increase in molecular mass. This suggests that N-glycosylation of LT109 improves its neutralizing capacity. Indeed, deglycosylation of LT109 decreased its neutralizing capacity three- to fivefold. We also studied the effect of glycosylation of two previously isolated VHHs on their ability to neutralize foot-and-mouth disease virus. For this purpose, these VHHs that lacked potential N-glycosylation sites were genetically fused to another VHH that was known to be glycosylated. The resulting fusion proteins were also N-glycosylated. They neutralized the virus at at least fourfold-lower VHH concentrations as compared to the single, non-glycosylated VHHs and at at least 50-fold-lower VHH concentrations as compared to their deglycosylated counterparts. Thus, we have shown that N-glycosylation of VHHs contributes to toxin- and virus-neutralizing capacity

De eiwitbehoefte van vleesstieren

In ons land hebben de stierenvleesproducenten de neiging, ondanks de hogere prijs voor het krachtvoer, meer eiwit aan de stieren te verstrekken dan volgens de geldende CVB-normen noodzakelijk is. Tal van buitenlandse proeven geven geen eensluidend antwoord op de vraag welke hoeveelheid eiwit een stier per dag nodig heeft voor een optimale groei