Evaluation of the Immunogenicity of Salmonella typhimurium Flagellar (H) Antigens and their Effect on the Tissues of White Male Rats

Abstract

Fifty blood samples were collected from patients suspected of having typhoid fever, and all clinical blood samples were subjected to serological diagnosis of salmonella, where 30 positive samples were obtained with a percentage of 60% and 20 samples negative with a percentage of 40%, and after isolation we noticed the absence of growth for four samples with a percentage of 13.3%, while 26 samples with a percentage of 86.6% showed a positive growth, which were carried out by phenotypic, microscopic, biochemical diagnosis and diagnosis using Vitek 2 Compact technique. 11 isolates were obtained with a percentage of 42.3% for S Salmonella typhi, 10 isolates with a percentage of 38.4% for Salmonella typhimurium, and 5 Isolates with a percentage of 19.2% for Salmonella paratyphi. The flagella antigen was extracted for S.typhimurium, and the lethal half-dose (LD50) test result showed that it was 1×10-4 cell/ml. The results of the phagocytic index (PI) for detecting the efficiency of flagella antigens showed an increase in the phagocytic index with the increase in the dilution of flagellated antigen,a high indicator of phagocytosis with an average of 71.205, the 10-4 dilution was the highest indicative with an average of 75.50, at the same time the dilutions showed a high reading of the Arthus index with an average of 2.040 and the delayed hypersensitivity (DTHR) with an average of 2.086, in which the 10-4 dilution was the highest reading with an average of 2.611 and 2.665, respectively. To confirm the high immunogenicity of this antigenic dilution, this dilution was used in the experimental immunization, which showed many secret signs that appeared on the rats, such as diarrhea, lethargy, high temperature and a high antibody index with an average of 160 mg / liter. The tissue slides showed the effect of all the organs studied, and the appearance of infections, infiltrates, ruptures of the cytoplasm of cells, and an increase in the proportion of blood cells and macrophages, which shows the acute immune reaction resulting from immunization with flagella antigen and its toxic effect on some organs.