Human polyclonal antibodies (hPABs) are useful in the treatment of numerous diseases, but as they are currently only derived from human donors their use has been limited. However, in August 12 advanced online Nature Biotechnology, Yoshimi Kuroiwa and colleagues, from a joint venture between Hematech — a biotechnology company in Westport, Connecticut — and Kirin — a Japanese brewer with substantial pharmaceutical interests — show they have generated cloned calves that can produce significant amounts of human antibodies (Nat Biotechnol 2002, DOI:10.1038/nbt727).

Kuroiwa et al. prepared a human artificial chromosome (HAC) vector containing the entire unrearranged sequences of the human immunoglobulin (hIg) heavy-chain (H) and lambda (λ) light-chain loci. They used the HAC vector to produce cloned bovine fetuses, from which four healthy transchromosomic (Tc) calves were generated. They observed that the newborn Tc calves retained the HAC at a high rate (78–100% of...