[Immunogenicity in Salmonella gallinarum-pullorum irradiated with gamma rays].

Studied with the imunogenicity of Salmonella gallinarum-pullorum bacteria treated with 1, 10 and 20 MR gamma rays or killed with acetone. Bacterial cultures were irradiated with a LMB-gamma M device, having a 137Cs source, single doses being of a 3,252 R/min power Biozzi's clearance test was employed to determine the changes in the immunogenic properties of the irradiated bacteria. The results obtained with both the clearance test and the protection test spoke of a considerable drop in the immunogenic capacity of the irradiated bacteria, using rates of 10, and especially of 20 MR gamma rays as compared to those killed with acetone. Protection was manifested best by bacteria treated at the rate of 1 MR gamma-rays, which pointed to the possibility of their practical use in the immunoprophylaxis of pullorum disease in birds.