149 

 nucleic acid replication, transcription or translation. 

 Alpha-amanitin conjugates would appear to combine both 

 desirable qualities, inhibition of a vital cellular 

 enzyme present in low numbers within a cell and a well 

 defined single mechanism for conjugation to proteins. 

 The second aspect of targeting inhibitor-protein 

 conjugates is the specificity of the carrier protein. 

 ADGG-Con A conjugates were well characterized with re- 

 spect to binding specificities and resulted in targeting 

 to specific carbohydrate moieties. In comparison to con- 

 jugates of albumins or non-immune gammaglobulins, the Con 

 A conjugates possess a much greater specificity of action. 

 However, because of the universal distribution of carbo- 

 hydrate moieties on cells of all types, the specificity of 

 targeting of a-amanitin should be improved by use of cell 

 surface directed immunoglobulins. Further studies with 

 ADGG conjugates of anti-Thyl.2 antiserum are projected. 

 Use of this antibody from AKR/J mice will allow the 

 synthesis of conjugates that should have minimal, if any, 

 reactivity to the host animal. The conjugate should result 

 in specific targeting to Thy-1 antigen present on EL4 

 lymphocytic leukemia cells both in_ vivo and in. vitro . 

 Studies similar to those of Moolten et al., (1972) with 

 conjugates of anti-DNP immunoglobulin G and ADGG will allow 

 for quantitative investigation of conjugate receptor affin- 

 ities following the introduction of variable numbers of 

 toxin molecules into the carrier protein. The relationship 



