Induction of Transmucosal Protection by Oral Vaccination with an Attenuated Chlamydia.

Chlamydia muridarum has been used to study chlamydial pathogenesis because it induces mice to develop hydrosalpinx, a pathology observed in C. trachomatis-infected women. We identified a C.

Induction of transmucosal protection by oral vaccination with an attenuated .

has been used to study chlamydial pathogenesis since it induces mice to develop hydrosalpinx, a pathology observed in -infected women. We identified a mutant that is no longer able to induce hydrosalpinx. In the current study, we evaluated the mutant as an attenuated vaccine.

Human Macrophages Exhibit GM-CSF Dependent Restriction of Infection Regulating Their Self-Survival, Differentiation and Metabolism.

GM-CSF is an important cytokine that regulates the proliferation of monocytes/macrophages and its various functions during health and disease. Although growing evidences support the notion that GM-CSF could play a major role in immunity against tuberculosis (TB) infection, the mechanism of GM-CSF mediated protective effect against TB remains largely unknown. Here in this study we examined the secreted levels of GM-CSF by human macrophages from different donors along with the GM-CSF dependent cellular processes that are critical for control of infection.

High-Resolution Quantitative Mapping of Macaque Cervicovaginal Epithelial Thickness: Implications for Mucosal Vaccine Delivery.

Vaginal mucosal surfaces naturally offer some protection against sexually transmitted infections (STIs) including Human Immunodeficiency Virus-1, however topical preventative medications or vaccine designed to boost local immune responses can further enhance this protection. We previously developed a novel mucosal vaccine strategy using viral vectors integrated into mouse dermal epithelium to induce virus-specific humoral and cellular immune responses at the site of exposure. Since vaccine integration occurs at the site of cell replication (basal layer 100-400 micrometers below the surface), temporal epithelial thinning during vaccine application, confirmed with high resolution imaging, is desirable.

Cytomegaloviral hypophysitis in a simian immunodeficiency virus-infected rhesus macaque (Macacca mulatta).

Rhesus macaques experimentally infected with Simian Immunodeficiency Virus (SIV) experience immunosuppression and often opportunistic infection. Among the most common opportunistic infections are rhesus cytomegalovirus (RhCMV), a ubiquitous betaherpesvirus that undergoes continuous low-level replication in immunocompetent monkeys. Upon SIV-mediated immunodeficiency, RhCMV reactivates and results in lesions in numerous organ systems including the nervous and reproductive systems.

Magnitude and Quality of Cytokine and Chemokine Storm during Acute Infection Distinguish Nonprogressive and Progressive Simian Immunodeficiency Virus Infections of Nonhuman Primates.

Unlabelled: Acute human immunodeficiency virus (HIV) infection represents a period of intense immune perturbation and activation of the host immune system. Study of the eclipse and viral expansion phases of infection is difficult in humans, but studies in nonprogressive and progressive nonhuman primate (NHP) infection models can provide significant insight into critical events occurring during this time. Cytokines, chemokines, and other soluble immune factors were measured in longitudinal samples from rhesus macaques infected with either SIVmac251 (progressive infection) or SIVmac239Δnef (attenuated/nonprogressive infection) and from African green monkeys infected with SIVsab9315BR (nonpathogenic infection).

Establishment of a neonatal rhesus macaque model to study Mycobacterium tuberculosis infection.

Mycobacterium tuberculosis (Mtb) is the causative agent of human tuberculosis (TB) with an estimated 8.8 million new TB cases and 1.4 million deaths annually.

Epithelial stem cells as mucosal antigen-delivering cells: A novel AIDS vaccine approach.

A key obstacle limiting development of an effective AIDS vaccine is the inability to deliver antigen for a sufficient period of time resulting in weak and transient protection. HIV transmission occurs predominantly across mucosal surfaces; therefore, an ideal vaccine strategy would be to target HIV at mucosal entry sites to prevent infection. Such a novel strategy relies on the activation of mucosal immune response via presentation of viral antigens by the mucosal epithelial cells.

High cell-free virus load and robust autologous humoral immune responses in breast milk of simian immunodeficiency virus-infected african green monkeys.

The design of immunologic interventions to prevent postnatal transmission of human immunodeficiency virus (HIV) will require identification of protective immune responses in this setting. Simian immunodeficiency virus (SIV)-infected rhesus monkeys (RMs), a species that develops an AIDS-like illness following experimental infection, transmit the virus at a high rate during breastfeeding. In contrast, postnatal transmission of SIV occurs rarely or not at all in natural, asymptomatic primate hosts of SIV.

Vaccine protection by live, attenuated simian immunodeficiency virus in the absence of high-titer antibody responses and high-frequency cellular immune responses measurable in the periphery.

An attenuated derivative of simian immunodeficiency virus strain 239 deleted of V1-V2 sequences in the envelope gene (SIV239DeltaV1-V2) was used for vaccine/challenge experiments in rhesus monkeys. Peak levels of viral RNA in plasma of 10(4) to 10(6.5) copies/ml in the weeks immediately following inoculation of SIV239DeltaV1-V2 were 10- to 1,000-fold lower than those observed with parental SIV239 ( approximately 10(7.

Induction of a virus-specific effector-memory CD4+ T cell response by attenuated SIV infection.

We investigated simian immunodeficiency virus (SIV)-specific CD4+ T cell responses in rhesus macaques chronically infected with attenuated or pathogenic SIV strains. Analysis of SIVDeltanef-infected animals revealed a relatively high frequency of SIV-specific CD4+ T cells representing 4-10% of all CD4+ T lymphocytes directed against multiple SIV proteins. Gag-specific CD4+ T cells in wild-type SIV-infected animals were 5-10-fold lower in frequency and inversely correlated with the level of plasma viremia.

Expression of CD8alpha identifies a distinct subset of effector memory CD4+ T lymphocytes.

Circulating CD4+ CD8+ T lymphocytes have been described in the peripheral blood of humans and several animal species. However, the origin and functional properties of these cells remain poorly understood. In the present study, we evaluated the frequency, phenotype and function of peripheral CD4+ CD8+ T cells in rhesus macaques.

Intracellular cytokine staining for the characterization and quantitation of antigen-specific T lymphocyte responses.

Standard proliferation assays used for analysis of T cell function have significant shortcomings, including limited sensitivity, lack of quantitative readouts, and considerable variability. Recently, flow cytometric methods have been developed to allow multiparametric detection of cell surface antigens and intracellular cytokine expression in response to polyclonal stimuli and antigen. We have optimized an intracellular cytokine staining assay in the non-human primate model of AIDS, which allows us to identify antigen-specific T lymphocytes at the single cell level with high sensitivity, while reducing background staining to a minimum.

Optimization of intracellular cytokine staining for the quantitation of antigen-specific CD4+ T cell responses in rhesus macaques.

Standard proliferation assays used for analysis of CD4+ T cell function have significant shortcomings, including limited sensitivity, lack of truly quantitative readouts and significant variability. We have optimized an intracellular cytokine staining (ICS) assay in rhesus macaques which allows us to identify virus-specific CD4+ T cells at the single-cell level with high sensitivity while reducing background staining to a minimum. A variety of parameters were tested to determine the optimal experimental conditions necessary for the detection of antigen-specific CD4+ T cells in macaques.

Elevated interleukin-7 levels not sufficient to maintain T-cell homeostasis during simian immunodeficiency virus-induced disease progression.

Elevated levels of interleukin 7 (IL-7) have been correlated with various T-cell depletion conditions, including HIV infection, and suggested as an indicator of HIV disease progression (AIDS and death). Here, the assessment of pathogenic simian immunodeficiency virus (SIVmac239) infection in rhesus macaques demonstrated a clear association between a significant elevation in IL-7 levels and disease progression. In 5 macaques that progressed to simian AIDS and death, elevated IL-7 levels were unable to restore T-cell homeostasis.

DNA vaccine protection against challenge with simian/human immunodeficiency virus 89.6 in rhesus macaques.

Twelve Rhesus macaques were immunized by intramuscular injection of naked DNA encoding the SlVmac gag and nef genes, HIV-1 89.6 env and rev genes and the simian interleukin-12 (IL-12) gene. Six of the animals also received two intramuscular injections of gp140 89.

Emergence and kinetics of simian immunodeficiency virus-specific CD8(+) T cells in the intestines of macaques during primary infection.

In this report, three Mamu-A*01(+) rhesus macaques were examined to compare the emergence of simian immunodeficiency virus (SIV)-specific CD8(+) T cells in the intestines and blood in early SIV infection using a major histocompatibility complex class I tetramer complexed with the Gag(181-189) peptide. Fourteen days after intravenous inoculation with SIVmac251, large numbers of SIV Gag(181-189)-specific CD8(+) T cells were detected in the intestinal mucosa (3.1 to 11.

Characterization of SIV-specific CD4+ T-helper proliferative responses in macaques immunized with live-attenuated SIV.

Analysis of immune responses generated by live-attenuated simian immunodeficiency virus (SIV) strains may provide clues to the mechanisms of protective immunity induced by this approach. We examined SIV-specific T-helper responses in macaques immunized with the live-attenuated SIV strains SIVmac239deltanef and SIVmac239delta3. Optimization of the concentration and duration of antigenic stimulation resulted in the detection of relatively strong SIV-specific proliferative responses, with peak stimulation indices of up to 84.

Immunization with live attenuated simian immunodeficiency virus induces strong type 1 T helper responses and beta-chemokine production.

Immunization with live attenuated simian immunodeficiency virus (SIV) strains has proved to be one of the most effective strategies to induce protective immunity in the SIV/macaque model. To better understand the role that CD4(+) T helper responses may play in mediating protection in this model, we characterized SIV-specific proliferative and cytokine responses in macaques immunized with live attenuated SIV strains. Macaques chronically infected with live attenuated SIV had strong proliferative responses to SIV proteins, with stimulation indices of up to 74.

Postexposure immunoprophylaxis of primary isolates by an antibody to HIV receptor complex.

mAb B4 is a monoclonal antibody directed against HIV receptor complex. The antibody had broad neutralizing activity against HIV and provided postexposure prophylaxis to hu-peripheral blood leukocyte (PBL)-severe combined immunodeficient mice and chimpanzees. B4 recognized a complex receptor site for HIV on the T cell surface that includes CD4 and also may be influenced by interaction with HIV coreceptors.

Inhibition of simian immunodeficiency virus (SIV) replication by CD8(+) T lymphocytes from macaques immunized with live attenuated SIV.

Characterization of immune responses induced by live attenuated simian immunodeficiency virus (SIV) strains may yield clues to the nature of protective immunity induced by this vaccine approach. We investigated the ability of CD8(+) T lymphocytes from rhesus macaques immunized with the live, attenuated SIV strain SIVmac239Deltanef or SIVmac239Delta3 to inhibit SIV replication. CD8(+) T lymphocytes from immunized animals were able to potently suppress SIV replication in autologous SIV-infected CD4(+) T cells.

CD4-immunoglobulin G2 protects Hu-PBL-SCID mice against challenge by primary human immunodeficiency virus type 1 isolates.

CD4-immunoglobulin G2 (IgG2) is a fusion protein comprising human IgG2 in which the Fv portions of both heavy and light chains have been replaced by the V1 and V2 domains of human CD4. Previous studies found that CD4-IgG2 potently neutralizes a broad range of primary human immunodeficiency virus type 1 (HIV-1) isolates in vitro and ex vivo. The current report demonstrates that CD4-IgG2 protects against infection by primary isolates of HIV-1 in vivo, using the hu-PBL-SCID mouse model.

Involvement of the complement system in antibody-mediated post-exposure protection against human immunodeficiency virus type 1.

We previously reported that passive transfer of a murine V3-specific monoclonal antibody (BAT123) to hu-PBL-SCID mice challenged with HIV-1LAI confers postexposure protection from infection. The role of the Fc fragment of this antibody as well as the involvement of the complement system in protection were evaluated in vivo. When we compared the postexposure protection offered by BAT123 and CGP 47439, a chimeric form of BAT123 in which the murine Fc domain has been replaced by a human IgG1 Fc domain, CGP 47439 failed to provide postexposure protection against HIV-1LAI despite having similar pharmacokinetics and in vitro neutralizing activity.

Passive immunization with a human monoclonal antibody protects hu-PBL-SCID mice against challenge by primary isolates of HIV-1.

How well antibodies can protect against disease due to HIV-1 infection remains a pivotal but unresolved issue with important implications for vaccine design and the use of prophylactic antibody to prevent infection after accidental exposure to the virus and to interrupt transmission of virus from mother to child. Strong doubts about the possible utility of antibodies in vivo have been raised because of the relative resistance of primary viruses to antibody neutralization in vitro. Primary viruses are likely to be close to the viruses transmitted during natural infection in humans.