INTRAVITAL DEMONSTRATION OF SEQUENTIAL MIGRATION PROCESS OF LYMPHOCYTE SUBPOPULATIONS IN RAT PEYERS-PATCHES

Background & Aims: Although recirculation of lymphocytes through Peyer 's patches is important for specific immune defense, the intraorgan mi gration of lymphocyte subpopulations has not been clearly understood. The aim of this study was to compare the spatial distributions of labe led lymphocytes among various subpopulations in vat Peyer's patches. M ethods: Lymphocytes collected from intestinal lymph were separated int o CD4(+), CD8(+), and T and B cells, labeled with a fluorochrome carbo xyfluorescein diacetate succinimidyl ester, and injected into the jugu lar vein. Peyer's patches of recipient rats were observed by intravita l fluorescence microscopy. Results: No significant difference was foun d in the percentage of lymphocytes in transit or in the Yelling veloci ty among different subpopulations. Lymphocytes sticking to the venules increased in number at 10-20 minutes, with preferential adherence of CD4(+) cells to venules of 25-50 mu m and preferential adherence of B cells to the venules of a wider size range. After 30 minutes, extravas ated lymphocytes moved into the interstitium. B cells migrated from ve nules more quickly than CD4(+) cells. CD8(+) cells showed an intermedi ate pattern between CD4(+) and B cells in sticking and migratory behav iors. Subsequently, CD4(+) and CD8 cells preferentially appeared in pa rafollicular microlymphatics. Conclusions: Significant differences wer e observed among lymphocyte subpopulations in terms of spatial distrib ution of lymphocytes sticking to venules, migration into the interstit ium, and their lymphatic transport.