The adjuvant effect of CpG oligodeoxynucleotide linked to the non-toxic B subunit of cholera toxin for induction of immunity against H. pylori in mice.

The present study was carried out to test the immunostimulatory and adjuvant effects of the non-toxic B subunit of cholera toxin (CTB), CpG oligodeoxynucleotide (ODN) and CpG ODN linked to CTB (CTB-CpG) for generation of immunity against H. pylori in mice. Herein, we showed that CTB-CpG induces more potent proinflammatory cytokine and chemokine responses in the cervical and the mesenteric lymph nodes (CLN and MLN, respectively) cells in vitro compared with those of CTB and CpG ODN. The adjuvant effects of these agents were examined following intranasal immunization of C57Bl/6 mice with H. pylori lysate in combination with CpG ODN, CTB or CTB-CpG. All three immunization regimes resulted in high H. pylori-specific IgG antibody responses; however, only the CTB-CpG and, to some extent, the CpG ODN immunized mice mounted a sustainable IgG2c antibody response. Importantly, mice immunized with H. pylori antigen and CTB-CpG or CpG ODN, but not CTB, developed strong H. pylori-specific proliferative and IFN-gamma responses in their MLN CD4+ T cells upon recall antigen stimulation in vitro. These mice also had significantly lower bacterial load compared with the control-infected mice. Furthermore, the CTB-CpG and the CpG ODN immunized mice developed increased specific IgA antibody responses in their gastrointestinal tracts following H. pylori challenge. These results imply that CTB-CpG and CpG ODN, but not CTB, could serve as nasal adjuvants for induction of a H. pylori-specific Th1 type immunity in MLN and also a specific mucosal IgA antibody response in the gastrointestinal tract upon H. pylori challenge.

Orally administered CpG oligodeoxynucleotide induces production of CXC and CC chemokines in the gastric mucosa and suppresses bacterial colonization in a mouse model of Helicobacter pylori infection.

Bacterial DNA and unmethylated CpG oligodeoxynucleotides (CpG ODN) are known to be potent stimulators of the innate immune system in vitro and in vivo. We therefore investigated if oral administration of CpG ODN could enhance innate immunity in the gastric mucosa and control the extent of Helicobacter pylori infection in mice. Intragastric administration of a single dose of CpG ODN significantly increased local production of the CC chemokines macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, and RANTES and the CXC chemokine gamma interferon-inducible protein 10 in the stomach and/or the small intestine. Importantly, intragastric administration of CpG ODN to mice with an already established H. pylori infection, in the absence of any coadministered antigen, was found to reduce the bacterial load in the stomach compared to the load in H. pylori-infected control mice, while similar administration of non-CpG ODN had no effect on the bacterial load. The reduction in the bacterial numbers in the stomachs of mice treated with CpG ODN was associated with enhanced infiltration of immune cells and increased RANTES production in the gastric mucosa compared to the infiltration of immune cells and RANTES production in H. pylori-infected control animals. These findings suggest that intragastric administration of CpG ODN without antigen codelivery may represent a valuable strategy for induction of innate immunity against H. pylori infection.

Interleukin-12 (IL-12) and IL-18 are important in innate defense against genital herpes simplex virus type 2 infection in mice but are not required for the development of acquired gamma interferon-mediated protective immunity.

Using a combination of gene-targeted mice and neutralizing antibodies, we showed that interleukin-12 (IL-12) and IL-18 are important in the innate control of genital herpes simplex virus type 2 infection but were not found to be critical, either singly or in combination, for the development of a protective gamma interferon-mediated immune response.

Dendritic cell vaccination protects mice against lethality caused by genital herpes simplex virus type 2 infection.

We have evaluated the ability of antigen pulsed bone-marrow derived dendritic cells (bmDC), to induce protective immunity against a genital tract infection with herpes simplex virus type 2 (HSV-2) in mice. Intravenous but not vaginal administrations of bmDC pulsed in vitro with UV-inactivated HSV-2, or with purified HSV-2 envelope glycoproteins gave rise to complete protection against disease, as well as death caused by genital herpes infection. Protection was dependent on the antigens being presented by the bmDC as neither the antigens alone, nor the mock-pulsed bmDC prevented disease. Immunity was associated with HSV-2 specific IFN-gamma and antibody production, and was shown to be dependent on CD4(+) cells secreting IFN-gamma. Thus, ex vivo antigen-pulsed bmDC represents a powerful tool for the study of protective immunity to genital herpes infection, and for the identification of protective antigens. These findings might also have an impact on the design of vaccines against other sexually transmitted viral diseases.

Protective vaccination against genital herpes simplex virus type 2 (HSV-2) infection in mice is associated with a rapid induction of local IFN-gamma-dependent RANTES production following a vaginal viral challenge.

PROBLEM: To investigate the production of the CC chemokines RANTES. MCP-1, and MlP-1alpha in the vaginal mucosa following HSV-2 challenge in vaccinated and unvaccinated mice. METHOD OF STUDY: The concentrations of the chemokines were determined in the vagina of HSV-2-vaccinated as well as unvaccinated mice after HSV-2 challenge using a PERFEXT method combined with ELISA. RESULTS: HSV-2 infection did not induce any measurable levels of MIP-1alpha, whereas high levels of RANTES and MCP-1 were detected in unvaccinated animals at 48 hr post challenge. The vaccinated mice developed a more rapid induction of RANTES, but not of MCP-1, appearing as early as 24 hr post challenge. The local induction of RANTES production was preceded by a vaginal IFN-gamma response. Furthermore, vaccinated IFN-gamma-/- mice did not produce any enhanced levels of RANTES following HSV-2 challenge. CONCLUSIONS: The protective immune response against genital HSV-2 infection is associated with a rapid induction of local IFN-gamma-dependent RANTES production.