Influence of circadian light-dark alternations on macrophages and lymphocytes of CBA mouse

The influence of circadian 12 h light-12 h dark alternations on CBA mouse macrophages and lymphocytes was determined using tests for macrophage spreading and ingestion ability or flow cytometry immunophenotyping of blood, lymph node, and spleen lymphocytes. The animals were tested every 4 h around the clock. Collected macrophages were incubated in vitro for 3 or 18 h. Monoclonal antibodies permitted detection of T-lymphocytes, suppressor-cytotoxic T-lymphocytes, helper-inducer T-lymphocytes, or B-lymphocytes. Two types of analyses were performed: First, the difference between the same intervals of the 12 h light or dark period was determined. The macrophage ingestion was significantly lower at the beginning and higher at the end of the dark period. We have also found a significant increase in blood T-lymphocytes of helper-inducer T-lymphocyte percentages and of the T helper-inducer: T suppressor-cytotoxic ratio during the dark period. Second, the ultradian variation during the 12 h light or dark period was determined. The variability was significant both for macrophage spreading and ingestion. Multiple significant variations of lymph node, spleen, or blood lymphocyte percentages were also observed. All of these data indicate that daily alteration of the lighting regimen significantly influences mouse peritoneal macrophage functions and various lymphocyte subsets.