Figures & data
Figure 1 Schematic representation of Protocols used for PEGylation of RBC. Scheme 1: Iminothiolane-thiolation mediated PEGylation. Iminothiolane reacts with amino groups generating thiol groups in situ. These thiols are modified by maleimide-PEG (Mal-Phe-PEG). Scheme 2: DTSSP-thiolation mediated PEGylation. DTSSP is a cross-linking reagent and uses acylation chemistry to react with amino groups. On treatment with reducing agents, the S–S bond generates free thiols that can be modified by Mal-Phe-PEG. Scheme 3: Acylation chemistry mediated PEGylation. Succinimidyl propionate-PEG (SPA-PEG) acylates amino groups of proteins. In schemes 1 and 2 an extension arm is added on protein amino groups for PEGylation and in scheme 3 PEGylation of proteins is carried out without adding extension arm.
Table 1 Functional and serological properties of PEGylated RBCs
Figure 2 Microscopic evaluation of agglutination of PEGylated RBCs in the presence of anti-D. RBCs are PEGylated by (A) imnothiolane-thiolation mediated PEGylation using Mal-Phe-PEG-5000, (B) DTSSP-based-thiolation mediated PEGylation using Mal-Phe-PEG-5000, and (C) Acylation chemistry mediated PEGylation using SPA-PEG-5000.
Figure 3 Microscopic evaluation of agglutination of PEGylated RBCs in the presence of anti-A (A, C & E) and anti-D (B, D and F). RBCs are PEGylated by (A & B) imnothiolane-thiolation mediated PEGylation using Mal-Phe-PEG-5000 in step-1 and Mal-Phe-PEG-20000 in step-2, (C & D) DTSSP-thiolation mediated PEGylation using Mal-Phe-PEG-5000 in step-1 and Mal-Phe-PEG-20000 in step-2 (E & F) acylation chemistry mediated PEGylation using SPA-PEG-5000 in step-1 and SPA-PEG-20000 in step-2.
