HPMA copolymer-modified avidin: immune response.

Protein-polymer conjugates to be used in the pretargeted delivery of a photosensitizer to cells were synthesized and characterized. Avidin was modified by N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers bearing the photosensitizer, mesochlorin e6 mono(N-2-aminoethylamide) (Mce6). Synthesis of HPMA copolymer-avidin-Mce6 conjugates was carried out so that either predominantly single point attachment or multipoint attachment of copolymer chains to avidin would result. HPMA copolymer-avidin conjugates were used which retained specific binding activity to a lower affinity biotin analog. Antigen specific anti-avidin immune response was shown to be reduced six-fold in some HPMA copolymer-avidin conjugates when compared to immune response to unmodified avidin. HPMA copolymer itself was shown to elicit a very low (IgM) immune response.