Table 1.
Comparison of Experimental and Theoretical Results on Control of Diabetes by CD4+CD8− Thymocytes
| Thymocyte dose | Frequency of protected rats | |||
|---|---|---|---|---|
| Observed | Calculated | |||
| × 106 | ||||
| 5.0 | 11/15 | 11/15 (76%) | ||
| 2.5 | 10/15 | 10/15 (69%) | ||
| 1.25 | 7/12 | 8/12 (64%) | ||
| 0.625 | 2/4 | 2/4 (59%) | ||
| 25.0 | ND | 19/20 (94%) | ||
The expected number of prediabetic rats protected from development of diabetes by different doses of CD4+CD8− thymocytes was calculated using the statistical analysis detailed in the Appendix. The level of protection observed experimentally (Observed) is compared with predicted values (Calculated). Percentages in parentheses indicate the calculated frequencies of protection from diabetes. As indicated in the Appendix, to calculate the percentage of rats protected from diabetes by thymocyte transfer requires that values be ascribed to the frequency of diabetogenic cells and regulatory ones. For example, if the frequency of diabetogenic cells is assumed to be 1:32,000, then the frequency of regulatory cells is just 8% greater than this. It is evident that the theoretical predictions fit the experimental data only if the excess of regulatory cells over diabetogenic ones is small.