Either B7-1 or B7-2 is required for Listeria monocytogenes-specific production of gamma interferon and interleukin-2

Identification of novel genes in the memory response to Brucella infection by cDNA arrays

This study investigated memory responses in immune mice spleen cells to brucellosis by gene expression utilizing cDNA micro arrays. Out of a total of 1176 cDNA's 21 genes were differentially regulated in three independent experiments, and generally supported a Th1 type immune response. 10 genes were validated by real time PCR, and 3 genes (CD 86, CD 40 L and CD 132) were also analyzed by Flow Cytometry for surface protein expression. We extended these findings by studying the expression of five selected genes (IRF 1, SOCS 1, IL 2 R, IRF 7, and CXCR 4) in two independent groups of Brucella immunized mice. In this study we show the potential application of utilizing gene arrays to identify and establish new correlates of protection against a cell mediated immune response.

Treatment of mice with anti-CD86 mAb reduces CD8+ T cell-mediated CTL activity and enhances ocular viral replication in HSV-1-infected mice

PURPOSE

To determine the relative impact of the CD86 (B7-2) costimulatory molecule in protection against ocular HSV-1 infection.

METHODS

BALB/c mice were depleted of CD86 by antibody and depleted mice were examined for their ability to withstand HSV-1 ocular infection. Depleted mice were tested for the presence of virus replication, T-cell activation, survival, and eye disease.

RESULTS

Mice that had been depleted of CD86 had significantly higher titers of HSV-1 in their eyes compared to mock-depleted infected mice. However, the levels of corneal scarring between the two groups of mice were similar. Following ocular infection, the levels of class I MHC-restricted cytotoxic T lymphocytes (CTL) were significantly higher in mock-depleted mice than in CD86-depleted mice. Finally, adoptive transfer of primed CD8(+) T cells but not CD4(+) T cells to CD86-depleted mice resulted in a decrease in peak virus titers in the eyes, such that HSV-1 titers were similar to that of their mock-depleted counterparts.

CONCLUSIONS

These data demonstrate an important role for CD86 in the development of CTL and reduction of virus replication in the eyes of HSV-1-infected mice.

Role of CD28 for the generation and expansion of antigen-specific CD8(+) T lymphocytes during infection with Listeria monocytogenes

Infection of mice with the intracellular bacterium Listeria monocytogenes results in a strong CD8(+) T cell response that is critical for efficient control of infection. We used CD28-deficient mice to characterize the function of CD28 during Listeria infection, with a main emphasis on Listeria-specific CD8(+) T cells. Frequencies and effector functions of these T cells were determined using MHC class I tetramers, single cell IFN-gamma production and Listeria-specific cytotoxicity. During primary Listeria infection of CD28(-/-) mice we observed significantly reduced numbers of Listeria-specific CD8(+) T cells and only marginal levels of specific IFN-gamma production and cytotoxicity. Although frequencies were also reduced in CD28(-/-) mice during secondary response, we detected a considerable population of Listeria-specific CD8(+) T cells in these mice. In parallel, IFN-gamma production and cytotoxicity were observed, revealing that Listeria-specific CD8(+) T cells in CD28(-/-) mice expressed normal effector functions. Consistent with their impaired CD8(+) T cell activation, CD28(-/-) mice suffered from exacerbated listeriosis both after primary and secondary infection. These results demonstrate participation of CD28 signaling in the generation and expansion of Ag-specific CD8(+) T cells in listeriosis. However, Ag-specific CD8(+) T cells generated in the absence of CD28 differentiated into normal effector and memory T cells.

Protective effect of a traditional Japanese medicine, Bu-zhong-yi-qi-tang (Japanese name: Hochu-ekki-to), on the restraint stress-induced susceptibility against Listeria monocytogenes

In this study, the effect of traditional Japanese (Chinese) medicine, Bu-zhong-yi-qi-tang (Japanese name: Hochu-ekki-to, HOT), on the restraint stress treatment (RST)-induced susceptibility against Listeria monocytogenes (L. monocytogenes) was examined. When RST was performed every day for 10 h from the day of infection, the bacterial numbers were increased at 3 and 5 days after the infection. Oral pretreatment with HOT for 7 days prevented such increases. Pretreatment with HOT prevented the suppression of antigen-specific IFN-gamma production by RST. HOT also prevented suppression of macrophage accumulation, including MHC-class II positives, in the peritoneal cavity and their bactericidal activity by RST. HOT suppressed the serum corticosterone level elevated by RST in infected mice. Taken together, the suppression of corticosterone using HOT participates in the prevention of suppressions of the bactericidal activity of macrophages, migration of macrophages and antigen-specific IFN-gamma production of Th1 cells by RST. Our findings suggest that HOT is a useful drug for patients suffering from stress disease to reduce the susceptibility to bacterial infection.

Interleukin-12 neutralization alters lung inflammation and leukocyte expression of CD80, CD86, and major histocompatibility complex class II in mice infected with Histoplasma capsulatum

Histoplasma capsulatum induces a cell-mediated immune response in lungs and lymphoid organs of mammals. Resolution of primary infection in mice depends on interleukin-12 (IL-12), since neutralization of this monokine increases susceptibility to infection. The present study was designed to determine if blockade of IL-12 disrupts the protective immune response by altering the influx of lineage-specific cells into infected lungs and the numbers of cells expressing CD80, CD86, CD119, and major histocompatibility complex class II (MHC II) molecules. In mice given anti-IL-12, there was a 2.5-fold decrease in total numbers of T cells on days 3 to 10 of infection and a 4-fold increase in Mac-1/Gr-1(+) cells on days 7 and 10 compared to infected controls. CD80(+) lung cells from anti-IL-12-treated mice were 2- to 3-fold greater than those from controls on days 7 and 10, whereas the total numbers of CD86(+) cells were 2- to 3-fold less and MHC II(+) cells were 1.5- to 2-fold less on days 3 and 5. Cells expressing CD119 were reduced 1.5-fold on day 5. Treatment with monoclonal antibodies (MAb) to CD80, CD86, or both reduced the fungal burden slightly compared to that in rat immunoglobulin G-treated controls, whereas after IL-12 neutralization, blocking of CD80 reduced the tissue burden by 2. 5-fold and this correlated with a decrease in IL-4. Regardless, mortality was not altered by treatment with MAb to CD80 or CD86. We conclude that (i) IL-12 neutralization alters the nature of the inflammatory response in lungs and the expression of CD80 and CD86 on lineage-specific cells, (ii) the immune response during infection with H. capsulatum is controlled via mechanisms independent of the CD80 and CD86 costimulatory pathways, and (iii) decreased expression of CD86 and MHC II may modulate generation of optimal protective immunity.

Critical Role of CD28 in Protective Immunity Against Salmonella typhimurium

Efficient T cell activation requires both TCR signals and costimulatory signals. CD28 is one of the molecules that provide costimulatory signals for T cells. We used mice deficient in CD28 expression (CD28−/− mice) to analyze the role of CD28 in the immune response against the intracellular bacterium Salmonella typhimurium, the causative agent of murine typhoid fever. CD28−/− mice were highly susceptible to infection with wild-type S. typhimurium and even failed to control infection with attenuated aroA− S. typhimurium. More detailed analysis revealed that CD28−/− animals did not mount a T-dependent Ab response and were highly impaired in the production of IFN-γ. Thus, CD28 cosignaling is crucial for immunity against S. typhimurium. To our knowledge, this is the first report describing an essential role for CD28 in protective immunity against an intracellular microbial pathogen.

Functional Analysis of Mature Hematopoietic Cells From Mice Lacking the βc Chain of the Granulocyte-Macrophage Colony-Stimulating Factor Receptor

Mice with a null mutation of the βc chain of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 receptors (βc-null mice) develop an alveolar proteinosis-like lung disease. The pathogenesis of this disease is uncertain and, although a defect in alveolar macrophage function has been postulated, no previous analysis of mature hematopoietic cells in mice with alveolar proteinosis has been reported. Therefore, we undertook a functional analysis of the mature hematopoietic cell compartment in βc-null mice. In addition, we reexamined the roles of the GM-CSF receptor  chain and the βc chain in signaling by GM-CSF. Neutrophils and macrophages from βc-null mice were capable of normal survival and phagocytosis in the absence of stimulus and of similar levels of nitric oxide production in response to interferon-γ and lipopolysaccharide. GM-CSF–mediated augmentation of survival, phagocytosis, and hydrogen-ion production were absent in neutrophils from βc-null mice. Interestingly, we were unable to show any ability of the GM-CSF receptor -chain alone to mediate glucose transport in these cells. In keeping with the βc-null mice lung pathology, examination of lavage fluid from the lungs of βc-null mice showed increased cellularity. This was caused by an increase in the number of lymphocytes, neutrophils, and macrophages. Large foamy cells in the lavage fluid from βc-null mice were identified as macrophages using immunohistochemistry. Functional analysis showed that these βc-null alveolar macrophages were capable of phagocytosis but uptake of colloidal carbon and cellular adhesion were reduced. In summary, mature hematopoietic cells with a null mutation of the βc receptor were unable to perform GM-CSF–mediated hematopoietic cell functions including glucose transport, but responded normally to a range of other ligands.

Functional Analysis of Mature Hematopoietic Cells From Mice Lacking the βc Chain of the Granulocyte-Macrophage Colony-Stimulating Factor Receptor

Mice with a null mutation of the βc chain of the granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 receptors (βc-null mice) develop an alveolar proteinosis-like lung disease. The pathogenesis of this disease is uncertain and, although a defect in alveolar macrophage function has been postulated, no previous analysis of mature hematopoietic cells in mice with alveolar proteinosis has been reported. Therefore, we undertook a functional analysis of the mature hematopoietic cell compartment in βc-null mice. In addition, we reexamined the roles of the GM-CSF receptor  chain and the βc chain in signaling by GM-CSF. Neutrophils and macrophages from βc-null mice were capable of normal survival and phagocytosis in the absence of stimulus and of similar levels of nitric oxide production in response to interferon-γ and lipopolysaccharide. GM-CSF–mediated augmentation of survival, phagocytosis, and hydrogen-ion production were absent in neutrophils from βc-null mice. Interestingly, we were unable to show any ability of the GM-CSF receptor -chain alone to mediate glucose transport in these cells. In keeping with the βc-null mice lung pathology, examination of lavage fluid from the lungs of βc-null mice showed increased cellularity. This was caused by an increase in the number of lymphocytes, neutrophils, and macrophages. Large foamy cells in the lavage fluid from βc-null mice were identified as macrophages using immunohistochemistry. Functional analysis showed that these βc-null alveolar macrophages were capable of phagocytosis but uptake of colloidal carbon and cellular adhesion were reduced. In summary, mature hematopoietic cells with a null mutation of the βc receptor were unable to perform GM-CSF–mediated hematopoietic cell functions including glucose transport, but responded normally to a range of other ligands.