HIV mucosal vaccine: Nasal immunization with rBCG-V3J1 induces a long termV3J1 peptide-specific neutralizing immunity in Th1- and Th2-deficient conditions
T. Hiroi et al., HIV mucosal vaccine: Nasal immunization with rBCG-V3J1 induces a long termV3J1 peptide-specific neutralizing immunity in Th1- and Th2-deficient conditions, J IMMUNOL, 167(10), 2001, pp. 5862-5867
In the vaccine strategy against HIV, bacillus Calmette-Guerin (BCG), a live
attenuated strain of Mycobacterium bovis, is considered to be one of poten
tial vectors for mucosal delivery of vaccine Ag. We analyzed the induction
of the Ag-specific Ab response by nasal immunization with recombinant BCG v
ector-based vaccine (rBCG-V3J1) that can secrete the V3 principal neutraliz
ing epitope of HIV. Alice were nasally immunized with rBCG-V3J1 (10 mug) th
ree times at weekly intervals. Four weeks after the initial immunization, h
igh titers of V3J1-specific IgG Abs were seen in serum. These high levels o
f HIV-specific serum IgG responses were maintained for > 12 mo following na
sal immunization without any booster immunization. V3J1-specific IgG-produc
ing cells were detected in mononuclear cells isolated from spleen, nasal ca
vity, and salivary gland of the nasally vaccinated mice. Nasal rBCG-V3J1 al
so induced high levels of prolonged HIV-specific serum IgG responses in Th1
(IFN-gamma (-/-))- or Th2 (IL-4(-/-))-immunodeficient mice. Further, IgG3
was highest among V3 peptide-specific IgG subclass Ab responses in these im
munodeficient mice as well as in wild-type mice. In addition, this Ag-speci
fic serum IgG Abs induced by nasal immunization with rBCG-V3J1 possessed th
e ability to neutralize clinical isolate of HIV in vitro. These results sug
gested that the nasal rBCG-V3J1 system might be used as a therapeutic vacci
ne in addition to a prophylaxis vaccine for the control of AIDS.