Ruker, and H. particles (CVLPs). The CVLPs had sizes similar to those of BPV particles and were able to bind to the cell surface and penetrate the cell membrane. Oral immunization of mice with CVLPs induced gp41-specific serum immunoglobulin G (IgG) and intestinal secretory IgA. However, intramuscular immunization with the CVLPs resulted in similar amounts of gp41-specific IgG but low levels of secretory IgA. The antibodies specifically recognized the fixed HIV-1 gp41 on the cell surface. Importantly, the sera and fecal extracts from mice orally immunized with the CVLPs neutralized HIV-1MN in vitro. Thus, BPV-HIV-1 gp41 CVLPs may be used to prevent and to treat HIV-1 infection. Human immunodeficiency virus type 1 (HIV-1) envelope-specific neutralizing antibodies (NAbs) are generated late after initial infection, and the neutralizing antibody response is 1-Methyl-6-oxo-1,6-dihydropyridine-3-carboxamide weak in the infected individuals (2, 9, 33). It has been shown that several monoclonal NAbs isolated from HIV-1-infected individuals can globally neutralize diverse strains of HIV-1 (25, 40, 41, 42, 43, 44, 1-Methyl-6-oxo-1,6-dihydropyridine-3-carboxamide 45). In monkey studies, passive immunization with these human neutralizing monoclonal antibodies prior to challenge with chimeric simian/human immunodeficiency viruses completely prevented infection in some adult animals challenged intravenously or intravaginally and in neonatal monkeys challenged orally (3, 15, 18, 26, 32). Administration of the neutralizing antibodies such as 2F5 in HIV-1-infected humans resulted in reductions in viral loads (39). Thus, eliciting broadly neutralizing antibodies will be a major goal in HIV vaccine development. Furthermore, HIV is transmitted both venereally and hematogeneously. Mucosal tissues are the major sites of HIV entry and initial infection (5, 6). Therefore, an effective HIV vaccine must elicit both mucosal immunity, to contain sexually transmitted viruses, and systemic immunity, to contain viruses transmitted directly into the bloodstream (21). It has been shown that HIV-1-specific mucosal immunoglobulin 1-Methyl-6-oxo-1,6-dihydropyridine-3-carboxamide A (IgA) can interfere with viral infection at mucosal sites to protect the host (1, 4, 7, 8, 17, 20). Human monoclonal antibody 2F5 has been shown to neutralize a variety of laboratory strains and primary isolates of HIV-1 (25, 34, 35, 44). The 2F5 antibody recognizes the amino acid sequence ELDKWA, which is a highly conserved linear epitope among HIV-1 envelope glycoproteins (gp41) (13, 30, 35). It Mouse monoclonal to FAK would therefore be desirable to express such a conserved epitope in a vaccine to induce antibodies broadly reactive to HIV-1 strains. The chimeric influenza virus expressing the ELDKWA epitope elicited a neutralizing immune response against a series of HIV-1 strains in mice (29). Unfortunately, many other attempts to elicit NAbs having the properties of 2F5 by immunization with this peptide sequence expressed in a number of contexts have failed (12, 14, 22). Considering that mucosal immunization is frequently capable of stimulating both mucosal and systemic immunity, we looked for a mucosal vaccine vector which could present the HIV 2F5 epitope through the mucosal route. In addition, we wanted to choose a vector to which humans have not been exposed before, because the preexisting neutralizing antibodies against the vector induced by previous exposure may render the induction of HIV-1-specific antibody very difficult. We have previously used papillomavirus virus-like particles (VLPs) as the vaccine carrier to induce both mucosal and systemic cell-mediated immunity by oral immunization (38). Foreign peptides can be inserted into the viral capsid (L1) protein from bovine papillomavirus type 1 (BPV-1), resulting in chimeric VLPs (CVLPs) that can induce high levels of NAbs against the inserted peptide (10). Because BPV VLPs are not a human pathogen, the VLPs should be an ideal carrier for immunization in humans. Thus, we hypothesized that chimeric papillomavirus VLPs expressing the 2F5 epitope ELDKWA (BPV-gp41 CVLPs) could induce neutralizing antibodies against HIV-1 in both mucosal and systemic compartments by oral immunization. In this study, we generated BPV-gp41 CVLPs 1-Methyl-6-oxo-1,6-dihydropyridine-3-carboxamide expressing the ELDKWA epitope. Our data demonstrate that oral immunization with BPV-gp41 CVLPs induced both mucosal and systemic neutralizing antibodies. MATERIALS AND METHODS Cell lines. SF9 (and 4C and resuspended at 1% (vol/vol) with PBS.