STABILITY AND IMMUNOLOGICAL REACTIVITY OF RECOMBINANT MEMBRANE CD4 ELECTROINSERTED INTO THE PLASMA-MEMBRANE OF ERYTHROCYTES

Concentration-dependent electroinsertion of recombinant human membrane CD4 in human erythrocytes shows a saturation at an average of about 3 ,500 inserted CD4 epitopes per cell, detectable by flow cytometry. The erythrocyte recovery drops to 10% at this high level of electroinsert ion. Experimentally an optimum for cell recovery and insertion rate wa s found at about 2,500 CD4 epitopes per red blood cell. In vitro stabi lity assays by flow cytometry indicated a temperature- and medium-depe ndent decrease in the number of CD4 epitopes inserted per cell. This d ecrease is biphasic, with an exponential part during the first 24 h af ter electroinsertion followed by a much slower linear decay.