Investigation of activity of antilymphoid sera in cultures of human circulating blood lymphocytes

Abstract

Individual heterologous antilymphoid sera act differently on the blast-transformation reaction in mixed cultures of homologous human circulating blood lymphocytes. The effect of the antilymphoid sera depended on their activity in a lymphocyte monoculture.Heterologous antisera against lymphocytes (ALS) or thymocytes (ATS) of a recipient give rise to a marked immunodepressive effect during allografting [1,2,[7][8][9][10]12]. A convenient working model for studying the mechanism of action of antilymphoid sera on lymphoid ceils is a culture of circulating blood lymphocytes. In the presence of ALS, mitotic activity of lymphocytes in culture is stimulated [3,5,6,11]. However, there is no information in the literature concerning the effect of ALS on a mixed culture of lymphocytes.The object of this investigation was to study the action of various heterologous antisera against human lymphoid cells on monocultures and mixed cultures of circulating blood lymphocytes. EXPERIMENTAL Antisera were obtained by immunizing rabbits and horses with a suspension of human fetal lymphocytes or thymocytes~ The scheme of immunization and method of obtaining antisera were described by the writers previously. Altogether 8 antisera were obtained for testing: 4 rabbit ATS, 2 rabbit ALS, and 2 horse ALS. The antibody titer in the antisera was tested by the lymphocyte-agglutination reaction (LAR) and the lymphocytetoxic test (LCT).The blast-transformation reaction in monocultures and mixed cultures of lymphocytes (BTR) was carried out by the writers ~ modification of the method described in [4]. Monocultures and mixed cultures of homologous lymphocytes obtained from 23 apparently healthy persons were studied~ The activity of the antilymphoid sere was estimated by their ability to cause blast transforming, cytotoxic and leukocyte-agglutinating effects in vitro. The cytotoxic effect was assessed quantitatively from the relative number of lysed and degenerated ceils (under 10% +, 10-20%++, 30-40~c +++, 50-60~c++++, and 60% +++++). The effect of the antisera on the BTR in a mixed culture was assessed from the change in intensity of reaction of ceils preliminarily tested with ALS or ATS.In all series of experiments the following standard scheme of treatment of lymphocytes was used. Whole antiserum, in a dose of 0.1 ml per million lymphocytes, was added to the monoculture~ Treatment of the lymphocyte partners during cultivation was carried out in the presence of a dose of 0~ ml per million cells. After incubation for 30 rain at 37 ~ the cells were washed with medium No. 199 and mixed in the proportion of 1 : 1 for subsequent cultivation by the usual scheme.