Fruit and vegetables have therapeutic potential as they dampen inflammation, have no known side-effects and as whole foods have prospective additive and synergistic benefits. Th1 (IFN-γ(+) CD4(+))/Th2 (IL-4(+)CD4(+)) T cells play a vital role in mediating inflammatory responses and may be regulated by regulatory T cells (Tregs). Effects of Carica papaya on cells of healthy individuals were determined using flow cytometry methods. Significant down-regulation of IFN-γ(+) CD4(+) (p=0.03, n=13), up-regulation of IL-4(+) CD4(+) (p=0.04, n=13) T cells and up-regulation of CD3(+) CD4(+) CD25(+) CD127(-) (p=0.001, n=15) Tregs were observed after papaya consumption. In vitro cultures showed up-regulation of Tregs in male subjects and was significantly associated with levels of IL-1β in culture supernatants (R(2) =0.608, p=0.04, n=12). Other inflammatory cytokines were significantly suppressed. Papaya consumption may exert an anti-inflammatory response mediated through Tregs and have potential in alleviating inflammatory conditions.
Enterovirus 71 (EV71) is one of the viruses that cause hand, foot and mouth disease. Its viral capsid protein 1 (VP1), which contains many neutralization epitopes, is an ideal target for vaccine development. Recently, we reported the induction of a strong immune response in rabbits to a truncated VP1 fragment (Nt-VP1t) displayed on a recombinant Newcastle disease virus (NDV) capsid protein. Protective efficacy of this vaccine, however, can only be tested in mice, since all EV71 animal models thus far were developed in mouse systems. In this study, we evaluated the type of immune responses against the protein developed by adult BALB/c mice. Nt-VP1t protein induced high levels of VP1 IgG antibody production in mice. Purified VP1 antigen stimulated activation, proliferation and differentiation of splenocytes harvested from these mice. They also produced significant levels of IFN-γ, a Th1-related cytokine. Taken together, Nt-VP1t protein is a potent immunogen in adult mice and our findings provide the data needed for testing of its protective efficacy in mouse models of EV71 infections.
Animal studies suggest that inducible nitric oxide synthase (iNOS) may be associated with destructive periodontal disease. l-N(6)-(1-Iminoethyl)-lysine (L-NIL) has been shown to inhibit iNOS in a selective manner, and hence the aim of the present study was to test the hypothesis that treatment with l-NIL may induce a T-cell helper 1 (Th1)-like immune response by Aggregatibacter (Actinobacillus) actinomycetemcomitans lipopolysaccharide (LPS)-stimulated murine spleen cells in vitro. BALB/c mice were either sham-immunized or immunized with A. actinomycetemcomitans LPS. Spleen cells were stimulated with A. actinomycetemcomitans LPS in the presence or absence of L-NIL. Nitric oxide (NO), iNOS activity, specific IgG subclass antibodies, interferon-gamma (IFN-gamma), and interleukin-4 (IL-4) levels and cell proliferation were determined. The results showed that treatment with L-NIL suppressed both NO production and iNOS activity but enhanced specific IgG2a, IFN-gamma levels, and increased cell proliferation following stimulation with A. actinomycetemcomitans LPS-stimulated cells. The results of the present study suggest that inhibition of iNOS activity by L-NIL may skew the A. actinomycetemcomitans LPS-stimulated murine splenic immune response towards the Th1-like immune profile in vitro.
The aim of this study was to determine the role of macrophages in the Actinobacillus actinomycetemcomitans-induced murine immune response. BALB/c mice were given carrageenan solution by intraperitoneal injection before immunisation with heat-killed A. actinomycetemcomitans. Mice immunised with antigens and phosphate-buffered saline served as positive and negative controls, respectively. One week after the last immunisation, the delayed-type hypersensitivity (DTH) response was assessed by measurement of footpad swelling. Serum IgG and IgM anti-A. actinomycetemcomitans antibody levels and culture supernate levels of interferon (IFN)-gamma were determined by ELISA. The diameter of abscess formation was determined every 5 days. Sham-immunised spleen cells were transferred to carrageenan-untreated recipients (groups A and B) and to carrageenan-treated recipients (group D). Antigen-immunised spleen cells were transferred to carrageenan-untreated (group C) and carrageenan-treated (group E) recipients. The carrageenan-treated recipients in groups F and G received macrophages from antigen- and sham-immunised mice respectively. All mice except those in group A were immunised with antigen 24 h after cell transfer. After 1 week, a partial suppression of DTH response, reduced levels of IFN-gamma, serum IgG and IgM anti-A. actinomycetemcomitans antibodies and delayed healing were seen in carrageenan-treated mice when compared with the positive control. The immune response to A. actinomycetemcomitans in groups A, B and D was lower than that in groups C and E. Healing of the lesion in the former groups was also delayed when compared with the latter groups. The immune response and the healing of the lesion could be partially restored in carrageenan-treated mice that received antigen-pulsed macrophages (group F) but not in those that received naive macrophages (group G). These results suggest that macrophages play a partial role in the induction of the murine immune response to A. actinomycetemcomitans.