Protective efficacy of piperine against Mycobacterium tuberculosis.

Piperine a trans-trans isomer of 1-piperoyl-piperidine was evaluated for its immunomodulatory activity to enhance the efficacy of rifampicin in a murine model of Mycobacterium tuberculosis infection. In-vitro immunomodulation of piperine was tested on mouse splenocytes for lymphocyte proliferation, cytokine production and macrophage activation. Protective efficacy of piperine was tested in a mice infection model of M. tuberculosis for the activation of Th-1 response and synergistic combination efficacy with rifampicin. Murine splenocytes exposed to piperine exhibited proliferation of T and B cell, increased Th-1 cytokines and enhanced macrophage activation. Piperine (1 mg/kg) in mice infected with M. tuberculosis activated the differentiation of T cells into Th-1 sub-population (CD4+ / CD8+ subsets). There was an increase in secretion of Th-1 cytokines (IFN-γ and IL-2) by these cells. The qRT-PCR studies revealed corresponding increases in the mRNA transcripts of IFN-γ and IL-2 in the infected lung tissues. Combination of piperine and rifampicin (1 mg/kg) exhibited better efficacy of and resulted in additional 1.4 to 0.8 log reduction in lung cfu as compared to rifampicin alone. The up-regulation of Th1 immunity by piperine can be synergistically combined with rifampicin to improve its therapeutic efficacy in immune-compromised TB patients.

Possible role of macrophages induced by an irridoid glycoside (RLJ-NE-299A) in host defense mechanism.

In order to explore the possible role of macrophages and other necessary immune competent (T and B) cells in the modulation of immune responses, an attempt was made to study the immunomodulatory effect of an irridoid glycoside (RLJ-NE-299A) isolated from the roots of Picrorhiza kurroa. Both in vitro and in vivo studies were used to evaluate the effect of RLJ-NE-299A on humoral, cellular, and phagocytic activity of macrophages. The data obtained in the present study showed that RLJ-NE-299A significantly increased sheep red blood cell (SRBC) and induced antibody (IgM and IgG) titer and delayed type hypersensitivity (DTH) reaction in mice. Besides augmenting the humoral and cell-mediated immune response, it induced macrophage phagocytosis and stimulated cytokine-induced macrophage activation and nitric oxide (NO) production, which resulted in a high degree of protection against Candida albicans and Salmonella typhimurium infections. Flow cytometric analysis indicated the enhanced expression of co-stimulatory surface molecules CD80 and CD86. The ability of RLJ-NE-299A to upregulate these cell surface antigens involved in antigen presentation may provide an explanation for the increased T-cell mediated immunity involving macrophages. Taken together this in vitro and in vivo preclinical data suggests that RLJ-NE-299A acts as an effective immunomodulator specifically to improve macrophage function during infections. The effects of this agent on these cells at concentrations relevant to in vivo therapy support its immunopharmacologic application to modify cellular immunity.

A novel sarsasapogenin glycoside from Asparagus racemosus elicits protective immune responses against HBsAg.

The aim of the present investigation was to evaluate the adjuvant potential of a novel sarsasapogenin glycoside (immunoside) isolated from Asparagus racemosus in combination with hepatitis B surface antigen (HBsAg). Various in vitro and animal derived protocols were used to determine the response of immunoside adjuvanted with HBsAg and the results were compared with alum adjuvanted with HBsAg. Several biomarkers such as antibody titre (IgG, IgG1/IgG2a) were measured in mice sera. Cell proliferation, cytokines (IL-2, IFN-γ and IL-4), and lymphocyte sub-populations (CD4/CD8, CD3 and CD19) were determined in splenocytes from mice administered subcutaneously with test substances. In these cells CD4/CD8 derived IFN-γ release was also determined. Macrophage preparations were used for the determination of IL-12, IFN-γ and nitrite content. Seroconversion potential was compared with a standard vaccine. Acute safety evaluation of immunoside was done in mice. Effect of immunoside on red blood cell haemolysis was determined. The results have suggested that immunoside potentially enhanced anti-HBsAg immune response via augmenting Th1/Th2 response in a dose dependent manner.

Immunomodulatory activity of biopolymeric fraction BOS 2000 from Boswellia serrata.

Oral administration of BOS 2000 (1-10 mg/kg) elicited a dose related increase in the delayed hypersensitivity reaction (early 24 h and delayed 48 h) in mice. It also stimulated the IgM and IgG titre expressed in the form of plaques (PFC) and complement fixing antibody titre. The concentration of cytokines (IL-4, IFN-gamma and TNF-alpha) in serum with respect to T cell interactions, i.e. (CD4/CD8) and the proliferation of lymphocytes were significantly increased at 10 mg/kg compared with the control. The results in these studies demonstrated the immunostimulatory effect of BOS 2000 in a dose-dependent manner with respect to the macrophage activation possibly expressing the phagocytosis and nitrite production by the enhancement of TNF-alpha and IFN-gamma production as a mode of action.

A new vaccine adjuvant (BOS 2000) a potent enhancer mixed Th1/Th2 immune responses in mice immunized with HBsAg.

Adjuvants in vaccines are immune stimulants that play an important role in the induction of effective and appropriate immune responses to vaccine component. In search of a potent vaccine adjuvant, the water-soluble biopolymeric fraction BOS 2000 from Boswellia serrata was evaluated for desired activity. We investigated the ability of BOS 2000 to enhance HBsAg specific immune responses. The effect was determined in the form of protective anti-HBsAg titers, neutralizing antibodies (IgG1 and IgG2a), spleen cell lymphocyte proliferation by using MTT assay, Th1 (IFN-gamma and TNF-alpha) and Th2 (IL-4) cytokines as well as T-lymphocyte subsets (CD4/CD8) and intracellular cytokines (IFN-gamma/IL-4), these responses were highest in BOS 2000 immunized mice. Alum induced only a modest enhancement of antibody responses. Reducing the dose of adjuvant by 18.1-fold in comparison to alum, total IgG and its subtypes (IgG1 and IgG2a) antibodies titer in serum was significantly enhanced. Analysis of HBsAg specific cytokines revealed that alum was associated with a predominantly IL-4 response. In contrast, BOS 2000 was associated with production of both IFN-gamma and IL-4. We conclude that BOS 2000 is a potent enhancer of antigen-specific Th1 and Th2 immune responses in comparison to alum with Th2 limitation and is a promising adjuvant for vaccine applications.