A modified assay for the detection of human adult active rosette forming lymphocytes

A modified procedure is described for the detection of a sub-population of peripheral blood T-cells in normal human adults. This sub-population of T-cells has been called the active rosette forming cell by others. The advantages of this modified procedure compared with that previously described are: 1) the elimination of 60 mon incubation period for lymphocytes prior to the assay and 2) the elimination of the need for fetal calf serum in the assay. The mean percentage of RFC in the peripheral blood of 80 healthy adult controls using the modified procedure is 25.2+/-5.5% in buffer lacking FCS. The results were highly reproducible and comparable to the results obtained using the procedure previously described. It was concluded that a 60 min pre-incubation of lymphocytes and the use of FCS are not necessary when the appropriate SRBS: lymphocyte ratio is used in the determination of human adult active RFC. The use of this procedure in evaluating the immune competence of cancer patients is discussed.