The effect of tuberculin skin test and BCG vaccination on the expansion of PPD-specific IFN-gamma producing cells ex vivo.

Journal article

Understanding the immunogenicity of BCG in a population where it has failed will facilitate the design of new TB vaccines. We assessed the immunogenicity of M. bovis BCG over 12 months by ELISPOT assay. Forty-one adolescents and young Gambian male adults received a tuberculin skin test (TST) which was followed one week later by BCG vaccination, but the 23 control subjects received neither of these. TST alone significantly induced PPD-specific IFN-gamma producing cells. Twenty-three percent of subjects did not respond to BCG, which was associated with higher pre-existing ex vivo response to PPD. Paradoxically, amongst BCG responders there was a correlation between pre-existing response and subsequent response to BCG. We conclude that BCG is immunogenic, but this effector response is short-lived and can be limited in higher pre-existing anti-mycobacterial immunity, suggesting a possible threshold beyond which BCG immunogenicity is inhibited.

Authors: Ota, M; Brookes, R; Hill, P; Owiafe, P; Ibanga, H

• Publication status: Published
• Journal: Vaccine
• Volume: 25
• Issue: 52
• Pages: 8861-8867
• Publication date: 2007-12-01
• DOI: 10.1016/j.vaccine.2007.10.025
• EISSN: 1873-2518
• ISSN: 0264-410X
• Language: English
• Keywords: Mycobacterium bovis; Humans; Tuberculin Test; Adolescent; Leukocytes, Mononuclear; Lymphocytes; Tuberculosis Vaccines; Cells, Cultured; Gambia; Adult; Male; Interferon-gamma