A simplified microtechnique for measuring human lymphocyte proliferation after stimulation with mitogen and specific antigen.

Cutaneous leishmaniasis is a parasitic disease characterized by a marked cell-mediated response. In vitro measurements of this response in humans have so far been used to a limited extent probably because of the relatively large amounts of blood demanded for conventional cell proliferation studies. The microtechnique here described enables lymphocyte proliferation to be performed with small amounts of blood (100 microliter) which can be obtained by finger prick, and do not require Ficoll separation prior to cultivation of the mononuclear cells. The blood was aspirated into sterile capillaries, introduced into tubes containing heparin, and directly distributed into wells. The response to Leishmania major, to tuberculin purified protein derivative (PPD) and to mitogen was compared to the response of mononuclear cells after Ficoll separation, and no marked difference was found between the two methods. Using the described method, individuals cured from a Leishmania major infection showed a high response to the specific antigen, as compared to normal controls. The potential use of this microtechnique for epidemiological studies is discussed.