Study On The Legionella Pneumonia Antigen Composition And The Anti-Infection Effect Of IFN-γ To Legionella Pneumophila

Objective 1. To study whether there were the same antigens between Legionellapneumonia and other pathogenic bacteria causing pneumonia. 2. To observe the anti- infection effect of IFN-γ to Legionella pneumophila.Methods the Somatic antigens of Legionella pneumophila serogroup 1(LP1) was prepared, then two rabbits were immunized with the extraction several times, then the animals were killed and the serum were separated from the whole blood used as the anti- LP1 antibody. The bacterial membrane proteins were extracted including Legionella pneumophila sergroup 1 (LP1), Bacillus coli, Staphylococcus epidermidis , Hemophilies influenzae,Pseudomonas pyocyanea, Staphylococcus aureus, Streptococcus pneumoniae, and Bacillus canalis capsulatus. All the extracted membrane proteins were separated by SDS-PAGE gel electrophoresis, and the resulted protein bands were transferred to PVDF membrane, then tested by Western-blot assay.Guinea pigs infected with Legionella pneumophila sergroup 1 through trachea were randomly divided into two groups, the treated group and the control one. The former was treated with IFN-γ by intramuscular injection, the latter was treated with PBS. the infected symptoms of the 2 group here observed every day, 4 animals were killed at the 24h,48,72h, 120h and d after infection, respectively, the serumal CPK, GOT,GPT, AKP, BUN, Crand LDH were examined, the colonies of LP1 bacteria in corresponding lungs were counted, and the pulmonic pathology was observed.Results The SDS-PAGE gel stained with Coomassie showed that LP1' s mainbands were 154kDa, 97kDa> 79kDa> 58kDa ffl 44kDa, which confirmed by the result of Western-blot assay. The Western-blot assay showed that there were the same bands in the lanes of Staphylococcus epidermidis, hemophilies influenzae and Pseudomonas pyocyanea at the position of 154kDa and 97kDa; there were the same bands in the lanes of hemophilies influenzae and Pseudomonas pyocyanea at the position of 79kDa; there were the same bands in the lanes of Bacillus coli-, hemophilies influenzas,^ Bacillus canal is capsulatus at the position of 58kDa; there were the same bands in the lanes of Pseudomonas pyocyanea at the position of 44kDa; there were no bands in the lanes of Staphylococcus aureus and Streptococcus pneumoniae.The infection symptoms and the pathology were more minimal in treated group than that of the control group, in some infected animals, the level of G(7I\ AKP , BUN> Cr and LDH in serumal reduced partly in the former group, the bacterial colonies were markedly reduced in the same group in each period.Conclusion There were 3 same antigen epitopes in bacterial membraneprotein between LP1, Hemophilies influenzae, Pseudomonas pyocyanea and LP1; There were 2 ones between Staphylococcus epidermidis and LP1, and only one among Bacillus coliy Bacillus canal is capsulatus and LP1.This study showed that exogenous IFN- y can significantly enhance the inti-infection effect of guinea pigs to Legionella pneumophila sergroup 1.