The Stimulation of Dna Synthesis in Cultures of Rabbit Lymph Node and Spleen Cell Suspensions by Homologous Cells

Abstract

An early proliferative response follows the mixing of homologous spleen or lymph node suspensions obtained from two unrelated rabbits. The rate of incorporation of radioactive thymidine has been used as a quantitative measure of this response. Thymus cells do not respond to homologous cell suspensions but may on occasion serve to stimulate the response in homologous spleen or lymph node cells. Homologous erythrocytes or autologous tissues do not stimulate a response. No response occurs if the two cell populations are separated by a Millipore membrane. Autoradiographic studies have established that 1 to 2 per cent of the intial cell population is involved in the response and they are large undifferentiated cells by the time they can first be identified as responders. There was no morphological evidence of any cellular interaction and the viability of mixed suspensions was not measurably different from that observed in separate suspension. Simultaneous additive responses could be obtained to homologous cells and to antigen when cell suspensions from immunized rabbits were used. The interaction of the cell populations from the two rabbits did not appear to suppress the response of each to antigen. The speed and magnitude of the response were in everyway comparable with the secondary response of cell suspensions from immunized rabbits exposed to the immunizing antigen. No evidence was obtained of any enhancement of the response to homologous cells by prior immunization with homologous tissues, but the possibility that it had occurred was not rigidly excluded.

The Effect of Skin Homograft Rejection on Recipient and Donor Mixed Leukocyte Cultures

“…This response is inhibited by separating the spleen cell populations with a millipore filter. However, this does not inhibit the ability of PPD placed on one side of such a partition to stimulate cells on the other side (17). These findings favor the view that cell to cell contact is necessary for the mixed leukocyte reaction rather than mediation by a humoral factor.…”

Phytohemagglutin and Concanavalin A: Probes for M urine ‘T’ Cell Activivation and Differentiation

“…Attempts to activate thymocytes, however, with specific as well as nonspecific stimuli, have met with varied success. It is apparent that thymocytes from immunized animals cultured in the presence of specific antigen do not respond with either DNA synthesis (Chapman & Dutton 1965, Oppenheim et al 1967 or with antibody production (Andersson & Blomgren 1970). Staphylococcal filtrate, however, does cause marked DNA synthesis of rat (Knight & Thornbecke 1971) and rabbit (Knight & Ling 1969) thymocytes.…”

Impairment of Phytohaemagglutinin-Induced Blastic Transformation in Lymphnodes from Thymectomized Mice

“…It is pertinent, however, that some lymphoid populations exhibiting a greatly decreased immu nological reactivity, such as lymphocytes from the thymus (12,48,76,82) or from the blood of patients with chronic lymphatic leukaemia (4,8,56,58,63,71,77,81), Hodgkin's disease (2,35), ataxia-telangiectasia (59), or with certain types of agamma-D ukor/D ietrich, Impairm ent of Phytohaemagglutinin-Induced globulinacmia (13,27) have repeatedly been found to respond very poorly to PHA in vitro. Moreover, peripheral blood lymphocytes from patients undergoing immunosuppressive chemotherapy were shown to exhibit a greatly reduced transformation rate following exposure to PHA (36).…”