The fatty acid composition of the lymphocyte cell membrane. Influence on interactions with high endothelium and the expression of homing receptors.

By incubating mouse lymphocytes in vitro with various fatty acids in an otherwise lipid-free medium, the lipid composition of the cell membrane was varied. These changes resulted in an altered adhesion pattern on High Endothelial Venules (HEV) using an in vitro adherence assay. Incubation with linoleic acid (18:2) resulted in an increased adherence of T and B lymphocytes, linolenic acid (18:3) had no influence and both arachidonic acid (20:4) and arachidic acid (20:0) resulted in a decreased adherence of the two cell types when the adherence assay was performed using HEV from peripheral lymph nodes. Using HEV from mucosa associated Peyer's patches, T and B cells incubated with arachidic acid or arachidonic acid were less able to adhere this type of HEV. After incubation with linoleic acid, T lymphocytes adhere better to the Peyer's patches HEV whereas B cells showed a decrease in adherence and linolenic acid resulted in a decreased adherence of only B lymphocytes. FACS analysis revealed that MEL-14 expression as well as the expression of LFA-1 was somewhat elevated in intensity on T and B lymphocytes after incubation with linoleic acid. In contrast, the intensity for MEL-14 had decreased after arachidic acid or arachidonic acid. In case of arachidic acid the LFA-1 expression had also decreased. No changes were found after incubation with linolenic acid. The results suggest a role for the lipid composition of the membrane in recirculation patterns of lymphocytes.