Immunity to CRISPR Gene Editing poses a challenge, says a research

CRISPR-Cas9 is the latest buzz in biotechnology. CRISPR technology has offered huge hopes that it can cure most genetic disease, with positive impact for millions.

However, a bioRxiv preprint of a new study has a potentially disturbing result. It says that many people may already be immune to the most widely used forms of CRISPR. The tool could trigger an adaptive immune response when used therapeutically. Although this is a preliminary result, it will be an important consideration for clinical trials of CRISPR in humans, which are expected to begin shortly.

The authors of the study noted that the most widely-used versions of the protein are extracted from the bacteria Staphylococcus aureus (S. aureus) and Streptococcus pyogenes (S. pyogenes). In bioengineering, particular bacteria—usually selected for being widely available and easy to cultivate—are often used to synthesize particular proteins. For example, most of our medical insulin is made from genetically modified E. coli. The researchers behind the study questioned whether because S. aureus and S. pyogenes regularly infect humans we might have built up some resistance to their proteins already. The infections they cause, often called strep and staph, are widespread enough that most people can be expected to have been exposed to the bacteria.

The study discovered that in many cases, human immune systems produced T-cells that specifically responded to the Cas9 protein from Staphylococcus aureus. This suggests that attempts at therapeutic use would cause an adaptive immune response that might render the therapy ineffective. Indeed, the authors of the paper wrote that use of these proteins in those who’ve been exposed to this bacteria could be harmful.