Biological effect of highly diluted CCK-8 solutions on LPS-induced proliferation of murine lymphocytes

Author(s): Cabaner, C., Bastide, M.

Journal/Book: Proc GIRI. 1991; 5: 16-17.

Abstract: The aim of this study was to test the effect of highly diluted solutions of CCK-8 (the carboxy-terminal octapeptide of cholecystokinin CCK) on the blastic transformation of murine B lymphocytes induced by the mitogen LPS. In this model. we previously observed an inhibitory effect of CCK-8 at concentration ranging from 10-7 M to 10-16 M. Our present study was undertaken to test the following hypothesis. Since it has been shown by us and others that some high dilutions of certain substances are better biological effectors than others, we asked the question whether murine lymphocytes would respond to a pool prepared by mixing several highly diluted solutions without shaking the final pool. To this end, we prepared three pools of CCK-8 by mixing equal portions of solutions in three different concentration ranges: pool 1, 10-10 M-10-20 M (10-10 molecules/ml); pool 2. 10- 22 M-10-30 M (< 1 molecule/ml); pool 3, 10-32 M- 10-40 M (<< 1 molecule/ml). Experiments were performed with solutions of CCK-8 stored at - 20'C and at + 4'C. The spleen cells were stimulated by LPS added either simultaneously with CCK-8 or after pretreating the cells with CCK-8 for one hour. The cells were used either immediately after isolation or after one hour at + 4\UON\response of B cells exposed to the different pools was always variable. We observed less variability when the test was performed with unfrozen solutions of CCK-8. The least variability was observed, in fact, when LPS-stimulated splenocytes were exposed to following individual solutions of CCK-8: 10-15 M, 10-26 M, 10- 36 M and 10-46 M. The 10-15 M solution inhibited the LPS-induced lymphoblastic transformation (13% ± 2); 10-26 M CCK-8 caused a slight stimulation (1 4 % ± 4); 10-36 M solution had no effect but 10 M strongly inhibited the mitogenic response (- 30% ± 4). We suggest that the pools tested did not express a unique type of information, but rather contained signal specific for each component in the pool. Furthermore. the reproducible activity of 10-46 M CCK-8 suggest that the information tran smitted by this solution was independent of the CCK-8 molecule itself.

Keyword(s): hom. br. exp. anim. imm

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