Bovine lymphocytes: enhanced E-rosette formation after storage or gradient centrifugation.

Incubation of bovine thymus lymphocytes with SRBCs for 1 hr or more at 0 degrees C during the E-rosette test gave higher rosette counts than tests receiving no such incubation. Further enhancement was seen if lymphocytes were stored in foetal calf serum (FCS) or BSA solutions at 4 degrees C for 18 hr prior to rosette tests. Best enhancement due to storage in BSA was seen when cells were subsequently tested in FCS. However, after storage in BSA many rosettes occurred when tests were done in BSA, Albeit few rosettes occurred in BSA without prior storage. Less enhancement was seen after storage in sodium metrizoate (NaM). Enhancement in FCS and 10% BSA occurred after 1 day, but not 2 or more days, of storage at 4 degrees C, but was not seen when cells were stored at 37 degrees C. Rosette formation was about doubled by centrifugation of lymphocytes through BSA gradients prior to rosette tests; centrifugation through NaM gradients had no such effect. It is suggested that rosette formation is a property of an immature bovine T cell, and that on storage some cells develop and subsequently lose the ability to form rosettes.