Vol. 44, No. 2, 2000
A STUDY ON THE PROTECTIVE ACTION OF Salmonella-SPECIFIC DIALYSABLE LEUKOCYTE EXTRACT
Arnaudov, At.
Regional Veterinary Research Institute
Plovdiv
Bulgaria
Summary
Dialysable leukocyte extracts (DLEs) are low molecular weight substances, resulting from disrupted leukocytes from immune donors. They can transfer specific cell-mediated immunity to naive recipients. In many cases, this passively transferred immunity possesses a protective action against some infectious and parasitic diseases. Current investigations show that specific DLEs protect experimental animals against infections with pathogenic strains of Salmonella. But the mechanisms of this protection are unknown.
Using the mouse model, we found that the specific DLEs posses an inhibitory action after the penetration and colonization by a of pathogenic strain of Salmonella choleraesuis. The treatment with a specific DLE decreases the number of CFUs in the spleen on days 3, 10, and 20 post infection. Under histological investigation, it was established that this treatment led to the preservation of the normal structure of the spleen and the small intestine of the infected mice. Owing to the lack of pathological changes, a diffuse proliferation of macrophages in the lamina propria of mucosa was also observed. Under electron microscope investigation, we found these changes, showing macrophage activation.
We accept that the protective action of the specific DLE against Salmonella choleraesuis should be mediated by the proliferation of activated macrophages in the lamina propria. The proliferation and activation of the macrophages are, perhaps, the result of the specific activation of cell-mediated immunity in which, probably, the sensitized CD4 + Th-1 lymphocytes secret mediators, activate and bring them to the attention of the microbe.
Key words: dialysable leukocyte extract; electron microscopy; Salmonella choleraesuis
References
Folia Veterinaria / 2000