Vaccine 22 (2004) 3774–3788 A comparative evaluation of nasal and parenteral vaccine adjuvants to elicit systemic and mucosal HIV-1 peptide-specific humoral immune responses in cynomolgus macaques Michael A. Egan a , Siew Yen Chong a , Michael Hagen a , Shakuntala Megati a , Eva B. Schadeck a , Priscilla Piacente a , Ben-Jiang Ma c , David C. Montefiori b , Barton F. Haynes c , Zimra R. Israel a , John H. Eldridge a , Herman F. Staats d,∗ a Wyeth Vaccines Research, Pearl River, NY 10965, USA, b Department of Surgery, Human Vaccine Institute, Duke University Medical Center, Box 2926, Durham, NC 27710, USA c Department of Medicine, Human Vaccine Institute, Duke University Medical Center, Box 3307, Durham, NC 27710, USA d Department of Pathology, Human Vaccine Institute, Duke University Medical Center, Box 3712, Durham, NC 27710, USA Received 25 July 2003; received in revised form 30 January 2004; accepted 1 March 2004 Available online 8 April 2004 Abstract Cynomolgus macaques were immunized by either the intramuscular (i.m.) or intranasal (i.n.) route with a HIV-1 peptide-based im- munogen (C4-V3 89.6P) alone, or formulated with novel adjuvants to evaluate the ability of the adjuvants to augment peptide-specific systemic and mucosal immune responses. A mutant cholera toxin, CT-E29H, or the combination of recombinant human IL-1 (rhIL-1) protein and recombinant human GM-CSF (rhGM-CSF) protein were tested as adjuvants for i.n. immunization, while a stable emulsion of a synthetic monophosphoryl lipid A (MPL) analogue (RC529-SE) plus rhGM-CSF protein was tested as an adjuvant for i.m. im- munization. Macaques immunized i.n. with peptide alone failed to elicit an anti-C4-V3 89.6P antibody response in serum. In contrast, all the tested peptide/adjuvant formulations elicited peptide-specific immune responses. RC529-SE/rhGM-CSF elicited the highest peak anti-peptide IgG geometric mean titer in serum (1:32,768 at week 25) followed by rhIL-1/rhGM-CSF (1:1217 at week 10) and CT-E29H (1:256 at week 25). Measurable SHIV neutralizing antibody responses were detectable in only one macaque immunized i.m. with pep- tide formulated with RC529-SE/rhGM-CSF. Macaques immunized by the i.n. route with peptide in combination with CT-E29H failed to elicit measurable antibody responses at nasal or genital mucosal surfaces. In contrast, antibody responses at the nasal and genital mu- cosa were detected in macaques immunized by the i.n. route with peptide in combination with rhIL-1/rhGM-CSF. However, antibody responses at the nasal and genital mucosa were highest in macaques immunized parenterally with peptide in combination with the adju- vants RC529-SE/rhGM-CSF. These results suggest that parenteral vaccine administration in combination with the appropriate adjuvant formulation can elicit vaccine-specific humoral immune responses in both systemic and mucosal compartments. © 2004 Elsevier Ltd. All rights reserved. Keywords: Peptide vaccine; Adjuvant; Mucosal immunity; Intranasal immunization 1. Introduction Despite more than 20 years of human immunodeficiency virus type-1 (HIV-1) related research, infection with HIV-1 remains a major public health threat. The World Health Organization estimates that in the year 2002, five million people were newly infected with HIV-1, approximately 42 million people were living with HIV-1 or suffering from ∗ Corresponding author. Tel.: +1-919-684-8823; fax: +1-919-684-5627. E-mail address: hfs@acpub.duke.edu (H.F. Staats). acquired immunodeficiency syndrome (AIDS), and 3.1 mil- lion individuals died as a result of AIDS-related diseases [1]. The development of a vaccine capable of altering the global impact of HIV-1 infection remains a high priority. A protective vaccine against HIV-1 infection will likely require a safe and effective adjuvant. Currently, aluminum salts (aluminum hydroxide, aluminum phosphate, aluminum potassium phosphate) are the only adjuvants approved for widespread use in humans by the Food and Drug Admin- istration, however, aluminum salts have been shown to be relatively ineffective as a mucosal adjuvants [2,3]. More 0264-410X/$ – see front matter © 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2004.03.011