FIGURE 3. Percentage (mean ± SD) of acid-resistant to total cell-bound radioactivity for radiolabeled T101 by PBMNC. Labeled T101 was allowed to bind to PBMNC at 4°C for 1 h to obtain surface labeling with minimal internalization. Aliquots of 10⁶ cells were then placed into separate tubes and supernatants were separated from cells. Immediately after separation, cells underwent acid wash and acid-resistant radioactivity was determined by counting cell pellets after centrifugation. This procedure was repeated at various times after transferring cell aliquots to incubator at 37°C. Acid-resistant fraction was determined by dividing activity in cell pellet after acid wash by total activity on cell after 1 h of incubation at 4°C.