Fengmin Zhou

Protection of macaques against vaginal SHIV challenge by systemic or mucosal and systemic vaccinations with HIV-envelope.

Background:Worldwide, the majority of human immunodeficiency virus (HIV) infections occur by heterosexual transmission. Thus, the development of a vaccine that can prevent intravaginal HIV infection is an important goal of AIDS vaccine research. Objectives:To determine which single or combination of systemic and mucosal routes of immunizations of female rhesus macaques with an HIV-1SF162 envelope protein vaccine induced protection against intravaginal challenge with SHIV. Design:Female rhesus macaques were immunized with an HIV-1SF162 envelope protein vaccine administered systemically (intramuscularly), or mucosally (intranasally), or as a sequential combination of both routes. The macaques were then challenged intravaginally with SHIVSF162P4, expressing an envelope that is closely matched (homologous) to the vaccine. Results:Macaques receiving intramuscular immunizations, alone or in combination with intranasal immunizations, were protected from infection, with no detectable plasma viral RNA, provirus, or seroconversion to nonvaccine viral proteins, and better preservation of intestinal CD4+ T cells. Serum neutralizing antibodies against the challenge virus appeared to correlate with protection. Conclusions:The results of this study demonstrate that, in the nonhuman primate model, it is possible for vaccine-elicited immune responses to prevent infection after intravaginal administration of virus.

Antibody-Mediated Protection against Mucosal Simian-Human Immunodeficiency Virus Challenge of Macaques Immunized with Alphavirus Replicon Particles and Boosted with Trimeric Envelope Glycoprotein in MF59 Adjuvant

ABSTRACT We have previously shown that rhesus macaques were partially protected against high-dose intravenous challenge with simian-human immunodeficiency virus SHIVSF162P4 following sequential immunization with alphavirus replicon particles (VRP) of a chimeric recombinant VEE/SIN alphavirus (derived from Venezuelan equine encephalitis virus [VEE] and the Sindbis virus [SIN]) encoding human immunodeficiency virus type 1 HIV-1SF162 gp140ΔV2 envelope (Env) and trimeric Env protein in MF59 adjuvant (R. Xu, I. K. Srivastava, C. E. Greer, I. Zarkikh, Z. Kraft, L. Kuller, J. M. Polo, S. W. Barnett, and L. Stamatatos, AIDS Res. Hum. Retroviruses 22:1022-1030, 2006). The protection did not require T-cell immune responses directed toward simian immunodeficiency virus (SIV) Gag. We extend those findings here to demonstrate antibody-mediated protection against mucosal challenge in macaques using prime-boost regimens incorporating both intramuscular and mucosal routes of delivery. The macaques in the vaccination groups were primed with VRP and then boosted with Env protein in MF59 adjuvant, or they were given VRP intramuscular immunizations alone and then challenged with SHIVSF162P4 (intrarectal challenge). The results demonstrated that these vaccines were able to effectively protect the macaques to different degrees against subsequent mucosal SHIV challenge, but most noteworthy, all macaques that received the intramuscular VRP prime plus Env protein boost were completely protected. A statistically significant association was observed between the titer of virus neutralizing and binding antibodies as well as the avidity of anti-Env antibodies measured prechallenge and protection from infection. These results highlight the merit of the alphavirus replicon vector prime plus Env protein boost vaccine approach for the induction of protective antibody responses and are of particular relevance to advancing our understanding of the potential correlates of immune protection against HIV infection at a relevant mucosal portal of entry.

β7-integrin-independent enhancement of mucosal and systemic anti-HIV antibody responses following combined mucosal and systemic gene delivery

Vaccination strategies that can block or limit heterosexual human immunodeficiency virus (HIV) transmissions to local and systemic tissues are the goal of much research effort. Herein, in a mouse model, we aimed to determine whether the enhancement of antibody responses through mucosal and systemic immunizations, previously observed with protein‐based vaccines, applies to immunizations with DNA‐ or RNA‐based vectors. Intranasal (i.n.) followed by intramuscular (i.m.) immunizations (i.n./i.m.) with polylactide‐coglycolide (PLG)‐DNA microparticles encoding HIV‐gag (PLG‐DNA‐gag) significantly enhanced serum antibody responses, compared with i.m., i.n. or i.m. followed by i.n. (i.m./i.n.) immunizations. Moreover, while i.n./i.m., i.n. or i.m./i.n. immunizations with PLG‐DNA‐gag resulted in genital tract antibody responses, i.m. immunizations alone failed to do so. Importantly, β7‐deficient mice developed local and systemic antibody responses following i.n./i.m. immunization, or immunization via any other route, similar to those of wild‐type mice. To compare the DNA with an RNA delivery system, immunizations were performed with VEE/SIN‐gag replicon particles, composed of Venezuelan equine encephalitis virus (VEE) replicon RNA and Sindbis surface structure (SIN). i.n./i.m., compared with any other immunizations, i.n./i.m. immunization with VEE/SIN‐gag resulted in enhanced genital tract but not serum antibody responses. These data show for the first time that mucosal followed by systemic immunizations with gene delivery systems enhance B‐cell responses independent of the mucosal homing receptors α4β7 and αEβ7.

Dynamics of acute and memory mucosal and systemic immune responses against HIV-1 envelope following immunizations through single or combinations of mucosal and systemic routes

In this study, immunizations at 2 weeks vs. 6 weeks intervals, with an HIV-1 envelope protein in adjuvants, through intra-nasal (IN), intra-muscular (IM), IN followed by IM (IN/IM) and IM/IN, were compared for induction of mucosal and systemic immune responses. IN/IM immunizations at 2, but not at 6, week intervals induced the highest mucosal and systemic immune responses compared to other immunization routes. Following a resting memory phase, IN boosting of IN/IM-immunized mice, compared to IM-boosting of IM-immunized mice, induced increased IgA responses. Thus, depending on the immunization intervals, IN/IM may be more effective than IM immunizations for short- and long-term immunity.

Long-term Protection in Hamsters against Human Parainfluenza Virus Type 3 Following Mucosal or Combinations of Mucosal and Systemic Immunizations with Chimeric Alphavirus-based Replicon Particles

No licensed vaccines are available to protect against parainfluenza virus type 3 (PIV3), a significant health risk for infants. In search of a safe vaccine, we used an alphavirus‐based chimeric vector, consisting of Sindbis virus (SIN) structural proteins and Venezuelan equine encephalitis virus (VEE) replicon RNA, expressing the PIV3 hemagglutinin‐neuraminidase (HN) glycoprotein (VEE/SIN‐HN). We compared different routes of intramuscular (IM), intranasal (IN), or combined IN and IM immunizations with VEE/SIN‐HN in hamsters. Six months after the final immunization, all hamsters were protected against live PIV3 IN challenge in nasal turbinates and lungs. This protection appeared to correlate with antibodies in serum, nasal turbinates and lungs. This is the first report demonstrating mucosal protection against PIV3 for an extended time following immunizations with an RNA replicon delivery system.

Prolonged Protection against Intranasal Challenge with Influenza Virus following Systemic Immunization or Combinations of Mucosal and Systemic Immunizations with a Heat-Labile Toxin Mutant

ABSTRACT Seasonal influenza virus infections cause considerable morbidity and mortality in the world, and there is a serious threat of a pandemic influenza with the potential to cause millions of deaths. Therefore, practical influenza vaccines and vaccination strategies that can confer protection against intranasal infection with influenza viruses are needed. In this study, we demonstrate that using LTK63, a nontoxic mutant of the heat-labile toxin from Escherichia coli, as an adjuvant for both mucosal and systemic immunizations, systemic (intramuscular) immunization or combinations of mucosal (intranasal) and intramuscular immunizations protected mice against intranasal challenge with a lethal dose of live influenza virus at 3.5 months after the second immunization.

Maintenance of long-term immunological memory by Ig+CD45R+ non-plasma B cells following mucosal immunizations

To determine whether long-term immunological B cell memory following mucosal vaccinations is maintained by terminally differentiated Ig-CD45R- plasma cells or Ig+CD45R+ B cells, we immunized mice orally with the non-toxic B subunit of cholera toxin (CTB) as a carrier protein haptenated with FITC (CTB-FITC) plus CT adjuvant. We found that the adoptive transfer of Ig+CD45R+ but not the Ig-CD45R- cells, resulted in higher numbers of FITC-specific IgA-secreting cells in the intestine as well as higher anti-FITC serum IgA titers, suggesting that long term B cell immunological memory following oral vaccinations preferentially resided within the Ig+CD45R+ B cell population.