Erratum.
In Mark Crawford's article "Genentech sues FDA on growth hormone" (News & Comment, 20 Mar., p. 1454), antibody response that occurs in some patients using Protropin was incorrectly portrayed as the result of the product's 192nd amino acid-a methionyl. While the methionyl may be involved in the antibody responses of a limited number of Protropin users, there is evidence that antibody formation is a result of a number of factors. In particular, the precise details of the manufacturing process appear to be the major factor in determining the antigenicity of growth hormone preparations.