Mediation of macrophage effector function by lymphokine.

The progressive effect of lymphokine contact on macrophages in vitro has been studied using various quantitative cytochemical techniques. Changes in the physiology of the macrophages have been seen rapidly after lymphokine contact. These appear to correlate with the functional effect of inhibition of migration. After more prolonged contact with lymphokine however, the macrophages exhibit different changes to their physiology and reach a state of enhanced cytochemical activity which has been termed 'activation'. By comparing the rapid effect of lymphokine to the changes seen after prolonged contact it is suggested that one can rationalize the apparent paradoxical effects of these soluble mediators which appear initially to 'turn off' the macrophage and subsequently 'activate' the same cell. In doing so an hypothesis is put forward as to how this mediator might work in vivo.