Progressive granuloma formation is a hallmark of chronic mycobacterial infection. Granulomas are localized, protective inflammatory reactions initiated by CD4؉ T cells, which contribute to control of bacterial growth and blockade of bacterial dissemination. In order to understand the costimulatory requirements that allow CD4؉ T cells to directly or indirectly induce granulomas, we studied granuloma formation after 6 weeks in Mycobacterium bovis BCG-infected CD28-and CD40 ligand (CD40L)-deficient mice and compared it to granuloma formation in infected wild-type inbred mice and infected cytokine-deficient mice. We characterized granulomas morphologically in liver sections, analyzed granuloma infiltrating cells by flow cytometry, and measured cytokine production by cultured granuloma cells. CD28-deficient mice have no defect at the local inflammatory site, inasmuch as they form protective granulomas and control bacterial growth. However, there are fewer activated T cells in the spleen compared to infected wild-type animals, and quantitative differences in the cellular composition of the granuloma are observed by flow cytometry. In CD40L-deficient mice, the granuloma phenotype is very similar to the phenotype in gamma interferon (IFN-␥)-deficient mice. Both IFN-␥-deficient and CD40L-deficient mice form granulomas which prevent bacterial dissemination, but control of bacterial growth is significantly impaired. The relative proportion of CD4 ؉ T cells in granulomas from both CD28؊/؊ and CD40L ؊/؊ mice is significantly decreased compared with wild-type animals. Both models demonstrate that the phenotype and activation stage of systemic T cells do not always correlate with the phenotype and activation stage of the localized granulomatous response.Granuloma formation around infected macrophage is a defining cellular response to mycobacterium infections. Layers of extracellular matrix enclose a microenvironment of infected cells and an intense inflammatory infiltrate. Granulomas eliminate bacteria and also protect surrounding host tissue from destructive inflammatory responses. Without granuloma formation, mycobacterial infections can become widely disseminated and frequently lethal, as occurs in human AIDS-associated tuberculosis or in the infection of SCID or recombinaseactivating gene-deficient mice (22,27,33,34). The involvement of T lymphocytes in initiation, regulation, and resolution of granuloma formation has been well documented for both human and murine infections (18,22).Murine models of Mycobacterium tuberculosis and Mycobacterium bovis infection have been used to study the role of cytokine regulatory networks in T lymphocyte-macrophage interactions (11). Mycobacterial infections induce a Th1-type T-cell response in which gamma interferon (IFN-␥) and tumor necrosis factor alpha (TNF-␣) play crucial roles in granuloma formation and function (6,9,21,23,30,39). In contrast to the extensive characterization of cytokine requirements for protective granuloma formation, the study of essential T-cell costimulatory sig...

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We present four modes of public religion—secularist, generalist pluralist, particularist pluralist, and exclusivist—and discuss conditions under which white evangelicals employ these different modes. Ethnographic research on white evangelicals participating in multifaith initiatives in Los Angeles, Portland, Boston, and Atlanta indicates that they prefer the secularist mode that avoids religious expression. In addition, the research indicates that when white evangelicals do participate in multifaith contexts where religious expression is encouraged, they prefer the particularist mode that uses faith-specific language rather than the generalist mode that invokes interfaith language. Quantitative data from a national study of community organizing organizations confirms that white evangelicals are more likely to participate in multifaith initiatives that operate in the secularist rather than a religious mode of public engagement. We anticipate that our analytic typology describing four modes of public religion will be valuable for future studies that examine the public engagement of religious actors.