Parameter estimates of the mathematical model and their 95% confidence intervals.

We fit the basic mathematical model (eqn. (1) – (6)) to the the data on migration of thoracic duct lymphocytes in rats using nonlinear least squares. In total we estimate 12 model parameters. We list i) the rate of TDL entrance into a particular organ from the blood (second column), ii) the percent of cells leaving the blood into a particular organ (, third column), iii) the rate of exit of TDLs from an organ to the blood (fourth column), and iv) the average residence time of TDLs in the organ (fifth column). The rate of migration of TDLs from the blood to all organs, , is 2.3 min or the average residence time of cells in the blood is 26 sec. The average residence time of cells in a particular organ is calculated as for blood, lung, liver, and spleen, and for SCLNs, MLNs, and PPs. Estimated fraction of cells migrating from the blood to the liver and dying is and the rate of cell migration from the blood to other organs in the body min. Exit rates from subcutaneous LNs, mesenteric LNs, and Peyer's patches (and, thus, residence times in these lymphoid tissues) are statistically similar as judged by the F-test for nested models (, ), and therefore these rates were fitted as a single parameter. The average estimated residence time of TDLs in these secondary lymphoid tissues is 9.9 hours.