Baseline mycobacterial immune responses in HIV-infected adults primed with bacille Calmette-Guérin during childhood and entering a tuberculosis booster vaccine trial.
BACKGROUND
Most new tuberculosis vaccines will be administered as a booster to subjects primed with bacille Calmette-Guérin (BCG) during childhood.


METHODS
We investigated in vivo and in vitro immune responses to mycobacteria in human immunodeficiency virus (HIV)-positive subjects in Tanzania primed with BCG during childhood and entering a tuberculosis booster vaccine trial. Tests included intradermal skin testing for Mycobacterium tuberculosis purified protein derivative (PPD) and Mycobacterium avium sensitin (MAS); lymphocyte proliferation assays and interferon (IFN)-gamma levels after stimulation with Mycobacterium vaccae sonicate (MVS), M. tuberculosis early secreted antigen (ESAT)-6, M. tuberculosis antigen 85 (Ag85), or M. tuberculosis whole-cell lysate (WCL); and determination of serum antibody to lipoarabinomannin (LAM).


RESULTS
A total of 888 subjects with CD4 cell counts > or = 200 cells/mm3 were enrolled. PPD and MAS test results were positive in 34% and 30% of the subjects, respectively. Proliferative responses were detected as follows: MVS, 6%; Ag85, 24%; ESAT-6, 21%; and WCL, 59%. IFN-gamma responses were 2%, 6%, 12%, and 38%, respectively. LAM antibody was detected in 28% of the subjects. Subjects were more likely to have detectable proliferative and IFN-gamma responses if they had positive PPD test results or CD4 cell counts > or = 500 cells/mm3. Overall, 94% of the subjects had evidence of primed mycobacterial immune responses.


CONCLUSIONS
Of HIV-positive BCG-immunized adults with CD4 cell counts > or = 200 cells/mm3 in Tanzania, 94% are primed for booster mycobacterial immunization.
Matee
Mecky
M
Muhimbili University College of Health Sciences, Dar es Salaam, Tanzania.
Lahey
Timothy
T
Vuola
Jenni M
JM
Mtei
Lillian
L
Cole
Bernard F
BF
Bakari
Muhammad
M
Arbeit
Robert D
RD
Horsburgh
C Robert
CR
Pallangyo
Kisali
K
von Reyn
C Fordham
CF
D000328:Adult; D001500:BCG Vaccine / Q000008:administration & dosage* / Q000276:immunology*; D018791:CD4 Lymphocyte Count; D015658:HIV Infections / Q000150:complications / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology*; D007117:Immunization, Secondary; D008213:Lymphocyte Activation / Q000276:immunology; D009161:Mycobacterium / Q000276:immunology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000150:complications / Q000517:prevention & control*
D001500:BCG Vaccine