The INTERCEPT Blood System for platelets and plasma employs the unique properties of our amotosalen HCl molecule to block the replication of DNA and RNA, preventing the proliferation of susceptible pathogens. For red blood cell pathogen inactivation, a similar treatment process has been developed using a different molecule called S-303.
Platelets and red blood cells are not inactivated by the crosslinking process because they do not require nucleic acids to function. Plasma is not inactivated by the treatment because it is an acellular product (proteins and liquid).
The interactions of amotosalen and S-303 with DNA and RNA are highly specific and occur with high frequency even at low concentrations of nucleic acids (Fig.1). Once inside a pathogen, the compounds dock in between the nucleic acid base pairs. Upon illumination with ultraviolet A light (amotosalen) or a change in pH (S-303), an interstrand crosslink is formed, "locking" the DNA or RNA together so that it can no longer replicate. These reactions require UVA light or pH change, and will not continue in the absence of these conditions.
Broad Spectrum of Inactivation
The crosslinking activity of amotosalen and S-303 is not limited to particular nucleic acid sequences or specific families of pathogens, so unlike testing procedures this blood safety method does not rely upon advance identification of potentially harmful organisms. The replication of a broad spectrum of viruses, bacteria and parasites, as well as leukocytes, can be inactivated with these treatment processes.