Bovine alpha-2-HS-glycoprotein functions as a booster antigen for efficiently stimulating humoral immune responses to CCR5 and SIVmac239 envelope glycoprotein

• Published in: Biochemical and biophysical research communications 2014-01, Vol.443 (1), p.301-307
• Main Authors: Otsubo, Yasuharu, Yashiro, Seizo, Nozaki, Kiyoteru, Matsuura, Kaoru, Kiyonaga, Kouhei, Mitsumata, Ryotarou, Takahashi, Yoshihiro, Masuyama, Mitsuaki, Muneoka, Atsunobu, Takamune, Nobutoki, Shoji, Shozo, Misumi, Shogo
• Format: Article
• Language: English
• Subjects: AIDS Vaccines - immunology; Alpha-2-HS-glycoprotein; alpha-2-HS-Glycoprotein - immunology; Animals; Antibodies, Viral - immunology; Antibody Formation; Antigens - immunology; Cattle; CCR5; Cross-reacting antigen; Cynomolgus; Gene Products, env - immunology; HIV Envelope Protein gp120; HIV Envelope Protein gp41 - immunology; HIV Infections - prevention & control; HIV-1 - immunology; HIV-1 vaccine; Human immunodeficiency virus; Human immunodeficiency virus 1; Immunity, Humoral; Immunization, Secondary - methods; Macaca fascicularis; Macaca mulatta; Receptors, CCR5 - immunology; Recombinant Proteins - immunology; Simian Immunodeficiency Virus - immunology; SIVmac239 ENV; Vaccines, Synthetic - immunology
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2013.11.098

•Reconstruction of the immune response in HIV-1-exposed seronegative subjects.•An immunogen that can induce antibodies against CCR5 and SIVmac239 ENV was designed.•The vaccine-induced immune responses should be maintained before exposure to HIV-1.•Bovine alpha-2-HS-glycoprotein functions as a booster antigen. The presence of anti-CCR5 and anti-HIV-1 envelope glycoprotein (ENV) gp41 antibodies (Abs) at sites of HIV-1 exposure was effective in preventing its transmission to HIV-1-exposed seronegative (ESN) subjects. Here, we design an immunogen that can induce Abs against CCR5 and SIVmac239 ENV simultaneously and show that bovine alpha-2-HS-glycoprotein (bAHSG) functions as a booster antigen for efficiently stimulating humoral immune responses to CCR5 and ENV. Initially, we generated a rhesus CCR5-derived cyclopeptide (cDDR5) conjugated with a recombinant trimeric SIVmac239 Env. When inguinally administered to rhesus macaques, the immunogen simultaneously induced both anti-CCR5 and anti-ENV Abs in sera, and the purified serum IgG fraction exerted an inhibitory effect on SIVmac239 infection in vitro. When further boosted with bAHSG, the responses of both Abs were significantly enhanced. To examine the cross-reactivity of bAHSG, it was administered to naïve cynomolgus macaques. The results showed a statistically significant increase in IgG response against cynomolgus CCR5 and SIVmac239 ENV, and the induction of neutralizing activity against SIVmac239. These findings suggest that bAHSG is useful for immune strategies aimed at generating Abs against CCR5 and ENV simultaneously to confer HIV-protective immunity.