The migration of lymphocytes across specialized vascular endothelium: VIII. Physical and chemical conditions influencing the surface morphology of lymphocytes and their ability to enter lymph nodes

Abstract

The introductory review amplifies the finding that simply holding lymphocytes in vitro reversibly compromises their ability to enter lymph nodes from the blood, although entry into the spleen is unaffected. The differential migration of T and B lymphocytes from the blood, lymphocyte traffic in athymic rats, and the secretion of a sulphated glycoconjugate by high endothelial cells in lymph nodes are also discussed. Original data are presented concerning the effects of varying the conditions under which lymphocytes are held in vitro (time, temperature, medium, centrifugation) on their ability to enter lymph nodes and also on their surface morphology. In general, conditions that reduced the number of microvilli and induced surface blebbing also tended to affect the delicate function of crossing specialized vascular endothelium; but there was no simple relationship between morphology and migratory behavior. The localization of lymphocytes to the bone marrow was augmented by holding them in vitro, and this effect was greater after holding at room temperature (RT) than at 0 degree C, in contrast to impaired entry into lymph nodes. Small amounts of heparin (10 units) injected along with lymphocytes significantly reduced early localization in lymph nodes. These findings have practical implications for the design of lymphocyte traffic experiments and are relevant to the mechanism of lymphocyte attachment to vascular endothelium, since the well-known effect of trypsinizing lymphocytes can be reproduced by maintenance in vitro.

Blood Leucocyte Subsets of the Rat: Expression of Adhesion Molecules and Localization Within High Endothelial Venules

“…By analysing the numbers of leucocyte subsets within the HEV, information about the in vivo interaction of leucocytes and HEV can be obtained without using the long separation and labelling procedures necessary to obtain and study pure populations of lymphocytes, NK cells, monocytes and granulocytes [13]. Such procedures easily lead to activation and alteration in the expression of adhesion molecules, which is different in each leucocyte subset [14,15], thus possibly altering the normal leucocyte/endothelium interaction [16][17][18]. In addition, two types of HEV were investigated because it has been shown that initial binding to peripheral lymph node HEV is mainly mediated by L-selectin [19].…”

Analyzing the Migration of Labeled T Cells In Vivo: An Essential Approach with Challenging Features

“…In addition, the congenic "label" is not diluted after multiple cell divisions. However, even under these conditions, the migratory properties of lymphocytes can be damaged by inappropriate in vitro handling (Ford et al, 1984). Therefore, it is necessary to control these adverse effects, which can be done by monitoring three parameters: (a) recovery: a total recovery between 80% and 90% of the injected T cells shows that the cells have been handled appropriately during the labeling procedure (Westermann et al, 1994); a lower recovery indicates that the cells have been damaged during in vitro handling, (b) lymph node entry: because only intact T cells are able to enter lymph nodes via high endothelial venules, the presence of T cells within lymph nodes shows that they are not damaged (approximately 5% of the injected cells are usually found in mesenteric lymph nodes 24 hours after injection [Smith and Ford, 1983]), (c) liver localization: damaged T cells are preferentially found in the liver, and more than 20% of the injected cells found in the liver at any time point after injection usually indicate severe cell damage (Smith and Ford, 1983).…”

The Endothelium of the High Endothelial Venule: A Specialized Endothelium with Unique Properties

“…Studies by Drayson and Ford [15] on the deafferentization of lymph nodes clearly showed that lym phocyte influx was strongly diminished be fore any reduction of the sulfate incorpora tion could be observed. Low sulfate incorpo ration in HEV of lymph nodes from athymic rats on the other hand did not show any reduced immigration of lymphocytes into these lymph nodes [41].…”