By Kerry Grens

The only data Allerca has released to the public are pictures of a Western blot and a DNA gel, posted on its Web site, and a summary of a DNA analysis conducted by Microbac, a company Allerca contracted. Martin Chapman, founder of Indoor Biotechnologies, a Virginia company that develops environmental tests to measure the presence of household allergens, says some of the data published on the Web site don't seem to add up.

One image shows the results of gel electrophoresis of PCR products using primers for fel d 1. Arrows point to four lanes derived from control cats, each with a band at 1.7 kb, which the image describes as denoting fel d 1. Six other lanes, derived from Allerca's hypoallergenic cats, show no bands at 1.7 kb. Two genes encode the proteins of each subunit. ^3,7 The gel does not indicate the subunit gene for which the primers were designed, although the gene for chain 1 of Fel d 1 is 1.7 kb (GenBank accession number X62477). Chain 2 is 2.4 kb (GenBank accession number X62478). Microbac's genetic analysis concludes, however, that mutations found in chain 1 "are documented in the literature as naturally occurring" and that "chain 1 is not responsible for the hypoallergenic effects of the Allerca cats." The company found that mutations in chain 2 differed for Allerca and control cats, but the company does not show data about chain 2 on its website.

Chapman takes less issue with the DNA gel than with Allerca's Western blot. Chapman explains that when Fel d 1 is run on gels, the molecular weight normally shows up at about 18 kDa, reflecting the two subunits of the molecule. ⁸ Under reducing conditions two bands appear, one at 14 kDa and another at 4kDa. ^8,9 However, control cats on Allerca's gel show no Fel d 1 bands at 18, 14, or 4 kDa. Rather, the hypoallergenic cats show bands at around 35 and 33 kDa, which are closer to the molecular weight of the native protein.

Comparison between Allerca's Western blot and a typical Western blot for Fel d 1. Allerca's control cats (lanes 1 and 2) lack any bands for Fel d 1, which is 18 kDa under nonreducing conditions (lanes B and C), and two bands at 14 and 4 kDa under reducing conditions (lanes D and E). 8

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"Even if it's a labeling issue," Chapman says, "the bands don't seem to match up." Why would control cats lack any bands for the protein and why do the hypoallergenic cats have Fel d 1 bands at a higher molecular weight? "The quality of this blot is just awful," Chapman says. "If that's an example of their science, it's just not very well worked out."