Abstract
Purpose: :
Toxoplasmosis is one of the most common causes of infectious retinitis. The occurrence of the disease, recurrence, clinical presentation and response to conventional therapy vary significantly among patients. In Europe and North America, the vast majority of infections are caused by type I, II and III strains while in South America other strains are more common. The goal of this study is to devise a non-invasive serological test that can easily and accurately determine the genotype and virulence properties of the Toxoplasma strain.
Methods: :
Serological typing is based on the fact that many host antibodies are raised against parasite proteins that are highly polymorphic among distinct strains. We therefore synthesized a cellulose peptide array containing 600 peptides from a large number of polymorphic Toxoplasma proteins. The array was screened serologically to identify those polymorphic peptides that can discriminate between infection with different strain types.
Results: :
Initial experiments demonstrated that the peptide array could correctly distinguish type II from type III infections. Furthermore, many new peptides that can discriminate between infection with different strain types were discovered. Interestingly, peptides from proteins known to be associated with higher Toxoplasma virulence could also discriminate sera from mice infected with these virulent strains. We are now testing sera from humans known to be infected with distinct strains to determine the unique serological "fingerprint" of each strain. We will then use this peptide array to correlate Toxoplasma genotype to the severity of toxoplasmic retinitis.
Keywords: uvea • inflammation