Cytofluorimetric analysis of gut-intraepithelial and mesenteric lymph node lymphocytes of tumour bearing mice fed with egg-white lysozyme

The effects of the oral administration of 100 mg/kg/day egg-white lysozyme (EWL) on the expression of CD3, CD4, CD8 and CD25 antigens of lymphocytes harvested from IEL and mesenteric lymph nodes (MLNL) were tested in mice bearing MCa mammary carcinoma. Lysozyme, after oral administration, retains its enzymatic activity along the entire small bowel and almost 10% of the administered dose is recovered 1 hr after treatment in the middle of the jejunum. Correspondingly, the number of cells expressing the test antigens in MLNL is greater than in controls after a few days of treatment and is maintained high up to the end of treatment but returns to control values after treatment withdrawal; CD4:CD8 ratio is decreased by EWL in favour of CD8 positive cells. Treatment with EWL does not modify the ratio between CD4+ and CD8+ cells vs controls in IEL nor does it change the % of CD3 positive cells or the expression of IL-2 receptor at this level. These data support the existence of the induction of an immunity communication by EWL along the axis GALT-mesenteric lymph nodes which is in agreement with the reported effects of the oral administration of EWL on tumour growth in experimental systems and on host immunity in humans.