ASSEMBLY OF AN ANTIBODY AND ITS DERIVED ANTIBODY FRAGMENT IN NICOTIANA AND ARABIDOPSIS

The yield and assembly of an IgG1 antibody and its derived F(ab) fragm ent were compared in Nicotiana and Arabidopsis. The results obtained s howed a lot of interclonal variability. For 45% of the primary transge nic calluses, antigen-binding entities represented less than 0. 1% of the total soluble protein (TSP). Only two of the 103 analysed transfor mants contained more than 1% of antigen-binding protein, with 1.26% be ing the highest yield. Analogous amounts of complete antibody and F(ab ) accumulated in primary callus tissue. Moreover, yields were in the s ame range for both species as far as primary callus tissue is concerne d. However, the accumulation of the F(ab) fragment in leaf tissue of r egenerated plants differed significantly between Nicotiana and Arabido psis. The F(ab) fragment accumulated to only 0.044% of TSP in Nicotian a leaves but up to 1.3% in Arabidopsis leaves. Furthermore, both speci es showed differences in the assembly pattern of the complete antibody . Whereas Arabidopsis contained primarily fully assembled antibodies o f 150 kDa, Nicotiana showed an abundance of fragments in the 50 kDa ra nge.