Detection And Analysis Of Antibody And CD4~+ Memory T Lymphocytes In Mice Immunized With BCG

Objective:After two successive BCG immunizations in Balb/c mice,anti-PPD antibody IgG,anti-PPD antibody IgM,and CD4+ memory T cells were detected to explore the changing trends and provide experimental data for clinical diagnosis of tuberculosis and BCG-related immune memory.Methods:1.Thirty-five female Balb/c mice were randomly divided into control group(5)(injection of physiological saline)and treatment group(30)(subcutaneous injection of BCG).The treatment group were divided into primary immunization group(15)and re-immunization group(15).2.Specific anti-PPD IgG?IgM antibody in serum was detected by indirect ELISA.3.The expression of CD3,CD4,CD44,CD62L on the surface of CD4+memory T cells in lung and spleen tissues were detected by immunohistochemistry.Results:1?At the 50th day after the primary immunization,the mean OD values of anti-PPD antibody IgG in the BCG immunized group and the control group were statistically significant.On the 60th day,re-immunization was performed.On the 65th day,the mean OD values of anti-PPD antibody IgG between the BCG-immunized group and the control group were statistically significant.However,during the whole immunization process,there was no significant difference in the mean OD values of anti-PPD antibody IgM between the BCG immunized group and the control group.2.Immunohistochemical staining of the lung sections revealed that CD3,CD4,CD44,and CD62L positive cells were mainly distributed around the bronchioles.2.1?There was no significant change in IOD values of CD3 in lung of each group(P>0.05).2.2?IOD of CD4 in lung of each group:The primary immunization group and reimmunization group were significantly higher than the control group(P<0.05).2.3?IOD of CD44 in lung of each group:The primary immunization group and re-immunization group were significantly higher than the control group(P<0.05),and the re-immunization group was significantly higher than the primary immunization group(P<0.05).2.4?IOD of CD62L in lung of each group:The primary immunization group and reimmunization group were significantly higher than the control group(P<0.05),and the reimmunization group was significantly higher than the primary immunization group(P<0.05).3?After immunohistochemical staining of spleen sections,the positive cells of CD3,CD4,CD44,and CD62L mainly distributed in the white pulp.3.1?IOD of CD3 in the spleen of each group:The re-immunization group was significantly higher than the control group and primary immunization group(P<0.05).3.2?There was no significant change in IOD values of CD4 in spleen of each group(P>0.05).3.3?IOD of CD44 in spleen of each group:The primary immunization group and re-immunization group were significantly higher than the control group(P<0.05),and the re-immunization group was significantly higher than the primary immunization group(P<0.05).3.4?IOD of CD62L in spleen of each group:The re-immunization group was significantly higher than the control group and primary immunization group(P<0.05).4?In the primary immunization group,the IOD values of CD3,CD4,and CD62L in the spleen were significantly higher than those in the lung(P<0.05).5?In the reimmunized group,the IOD values of CD3,CD4,CD44,CD62L in the spleen were significantly higher than those in the lung(P<0.05).Conclusion:1?After Balb/c mice were first immunized with BCG,anti-PPD antibody IgG showed an overall upward trend.After immunization again,anti-PPD antibody IgG could rapidly increase in the short term and maintained a high level for a long time.No significant change in anti-PPD antibody IgM.2.After primary and secondary immunization with BCG,the total CD4+memory T cells and CD4+TCM increased in the lung and spleen of mice.The total CD4+ memory T cells and CD4+ TCM in the spleen were higher than in the lung.