Preparation And Efficacy Evaluation Of Egg Yolk Immunoglobulin (IgY) Against Klebsiella Pneumoniae

Objective: To prepare specific chicken egg yolk immunoglobulin (IgY) against Klebsiella pneumoniae(K. pneumonia), evaluate its activity in vitro and in vivo.Methods: Specific IgY was produced by immunizing hens with formaldehyde killed K. pneumonia and purified by water dilution, salt precipitations and ultrafiltration. The purity and titer of IgY were detected by SDS-PAGE and ELISA, respectively. Growth inhibition of specific IgY at different concentrations to K. pneumonia was tested in liquid culture medium. Pneumonia model was established by nasal instillation of K. pneumonia (2×1011cfu/ml) at a dose of 100μl. Mice were randomly divided into six groups and protected differently: blank control group(no challenge,), negative control group(normal saline), cefoperazone group(1 mg/ml), dexamethasone group (0.5 mg/ml ), high dose specific IgY group (40 mg/ml), low dose specific IgY group (20 mg/ml). Mice were intraperitoneally injected from 1-day before challenge to 4-day after challenge at an interval of 24 h with the following doses (per 10g weight): dexamethasone group, 100μl before challenge and 150μl after challenge; other groups, 150μl before challenge and 250μl after challenge. Clinical manifestations of mice were observed, the changes of their weight, temperature, white blood cell (WBC) , death rates, bacterial in lung tissue, appearance of lung tissue and pulmonary pathology were estimated.Results: The purity of IgY obtained by water dilution, salt precipitations and ultrafiltration was similar with that of standard IgY. ELISA indicated that the titer of specific IgY reached to pick value 1600 on 40-45 day after the first immunization. Specific IgY at concentrations of 1~20 mg/ml inhibited the growth of K. pneumonia in a dose dependent manner. After infected with K. pneumonia, the body temperature, weight and WBC in blood of mice decreased obviously in all groups except the blank control group. But the changes of IgY group and positive control (dexamethasone and cefoperazone) groups were less than that of negative control group. K. pneumonia cells were found in lung tissue of mice in all groups except blank control. Injury degree of lung tissue of mice in IgY group and positive control groups were lighter than that of negative control group. Death rates of mice in each group were as follows: blank control group was zero, negative control group was 90% and others were 80%Conclusion: High-purity IgY was obtained by the applied methods. The specific IgY showed high titer and considerable growth inhibition activity to K. pneumonia. Specific IgY has potential to pneumonia of mice caused by K. pneumonia.