Subject(s)
Cattle/microbiology , Coxiella burnetii/genetics , Disease Reservoirs/veterinary , Placenta/microbiology , Q Fever/veterinary , Animals , Coxiella burnetii/classification , Coxiella burnetii/isolation & purification , Disease Reservoirs/microbiology , Female , Genotype , Goats/microbiology , Humans , Molecular Typing , Netherlands/epidemiology , Phylogeny , Pregnancy , Q Fever/epidemiology , Q Fever/microbiology , Sheep, Domestic/microbiology , Ticks/microbiologyABSTRACT
The therapeutic parenteral application of llama single-domain antibody fragments (VHHs) is hampered by their small size, resulting in a fast elimination from the body. Here we describe a method to increase the serum half-life of VHHs in pigs by fusion to another VHH binding to porcine immunoglobulin G (pIgG). We isolated 19 pIgG-binding VHHs from an immunized llama using phage display. Six VHHs were genetically fused to model VHH K 609 that binds to Escherichia coli F4 fimbriae. All six yeast-produced genetic fusions of two VHH domains (VHH2s) were functional in ELISA and bound to pIgG with high affinity (1-33 nM). Four pIgG-binding VHH2s were administered to pigs and showed a 100-fold extended in vivo residence times as compared to a control VHH2 that does not bind to pIgG. This could provide the basis for therapeutic application of VHHs in pigs.
