Replikins, according to some studies, are short peptide sequences characterized by recurring appearances of lysine and histidine residues. One study described these sequences as being 7 to 50 amino acids long, containing two or more lysine residues, at least one histidine, and a 6% or more concentration of lysine. [1] They are typically identified by calculating a "replikin count," which reflects the frequency of these sequences per 100 amino acids in a protein. [1] Some studies have proposed that increases in replikin concentration may correspond with rapid viral replication or changes in pathological behavior, including in the analyses of influenza outbreaks. [1] Replikins have also been investigated in experimental peptide vaccines and in studies exploring potential connections between genomic replikin counts and cancer lethality. [2] [3]
A method for identifying replikins was patented by Samuel and Elenore S. Bogoch in 2001. [4] The peptide group was first identified by a proprietary company called Replikins, who have trademarked the name "Replikin Count".
A 2011 study by Bogoch and Bogoch suggested that increases in "replikin counts" within influenza viruses, like H1N1 and H5N1, may happen before or during major outbreaks. [1] The authors also noted similar patterns in H5N1, where higher replikin concentrations were observed in strains linked to greater infectivity. [1] They proposed that these changes could act as early signals for emerging or rapidly spreading strains, although this idea has not been supported in broader research. [1]
A study tested a synthetic replikin peptide vaccine against a low-pathogenicity H5 influenza in chickens. [2] The authors reported that the vaccinated birds did not shed detectable virus after being challenged with the same strain. [2] They suggested that reducing virus shedding could lower the chance of low-pathogenic H5 viruses evolving into highly pathogenic forms, and mentioned that the vaccine could be delivered through mass application to the upper respiratory tract. [2]
A preprint by Bogoch and Bogoch reported that cancer types with higher "replikin counts" in their genomic proteins were associated with higher mortality rates. [3] The authors compared replikin counts across different cancer cell types and suggested that rapidly lethal cancers, such as glioblastoma and non-small-cell lung cancer, had some of the highest measured counts. They also described a related antibody called antimalignin antibody and claimed there was an increase in concentration during active cancer and returned to lower levels during remission. [3] The authors proposed that replikin concentration might connect to how rapidly certain cancers replicate, but these findings have not been independently confirmed. [3]