Xenogenic macrophage immunization reduces atherosclerosis in apolipoprotein E knockout mice

Induction of experimental autoimmune orchitis by immunization with xenogenic testicular germ cells in mice

We previously showed that immunization of mice with syngeneic or allogeneic testicular germ cells (TGC) alone induces autoimmune inflammation in the testes without using any adjuvant. In the present study, we examined testicular autoimmune response against xenogenic TGC antigens in mice. The mice were immunized with murine, rat or guinea pig TGC and then the histopathology, delayed type hypersensitivity (DTH) response and humoral autoimmunity were investigated. The results showed that immunization with not only murine but also rat TGC caused experimental autoimmune orchitis (EAO) with hypospermatogenesis in mice, while that with guinea pig TGC could not. The DTH response to murine TGC was significantly elevated in mice that had been immunized with murine or rat but not guinea pig TGC. Serum autoantibody to murine TGC was immunohistochemically detected in the mice immunized with either murine, rat or guinea pig TGC, however, the level of autoantibody detected by ELISA revealed significant elevation when mice were immunized with murine and rat TGC. With the immunoblotting after electrophoresis, the murine TGC proteins at molecular masses around 55kDa and 70kDa can be detected when incubated with sera from m-TGC and r-TGC groups. These results represent the cross-reactivity among TGC of the mouse, the rat and the guinea pig at the levels of humoral immunity and also demonstrate that the rat TGC could elicit significant DTH response to murine TGC with the resultant EAO. This is the first to succeed in EAO induction by the use of xenogenic TGC.

CD3 antibody and IL-2 complex combination therapy inhibits atherosclerosis by augmenting a regulatory immune response

Background

Accumulating evidence suggests that the balance between pathogenic effector T cells (Teffs) and regulatory T cells (Tregs) may be important for controlling atherosclerotic disease. We hypothesized that a combination therapy with anti‐CD3 antibody (CD3‐Ab) and IL‐2/anti‐IL‐2 monoclonal antibody complex (IL‐2 complex) aimed at increasing the ratio of Tregs to Teffs would effectively inhibit atherosclerosis in mice.

Methods and Results

We treated apolipoprotein E‐deficient mice fed a high‐cholesterol diet with vehicle, CD3‐Ab, IL‐2 complex, or their combination. Mice receiving the combination therapy had markedly reduced atherosclerotic lesions than mice treated with CD3‐Ab or IL‐2 complex alone. In addition, a striking increase in the Treg/Teff ratio of lymphoid organs and atherosclerotic lesions, along with plaque stabilization characterized by decreased macrophage content and increased collagen content was observed. The combination treatment also markedly reduced splenic Ly6C^high inflammatory monocytes and might induce a favorable macrophage phenotype change in atherosclerotic lesions.

Conclusions

Our results indicate that in addition to suppressing Teff responses, enhancing Treg‐mediated immune responses is more efficacious in preventing atherosclerosis, suggesting a novel therapeutic approach for atherosclerosis.

Boosted rat natural xenoantibodies cross-react with Enterococcus faecalis by targeting melibiose and L-rhamnose

Natural antibodies include a subset described as xenoantibodies considered to be directed at microorganisms and also cross-react with antigens of unrelated species. In this study, we generated T-cell-independent (TI) and T-cell-dependent (TD) xenoantibodies in Lewis rats with hamster and pig blood injections. TI anti-hamster and anti-pig IgM and IgG xenoantibodies cross-reacted with Enterococcus faecalis but not with Escherichia coli isolated from the blood of Lewis rats after cecal ligation and puncture (CLP). TI anti-pig IgM xenoantibodies also showed some reactivity with two human blood isolates of E. faecalis. In contrast, TD xenoantibodies did not show any reactivity with rat or human bacteria. TI and TD anti-hamster and anti-pig IgM and IgG xenoantibodies showed cross-reactivity with lymphocytes and endothelial cells from species distinct to that used for immunization. Glycan array analysis and inhibition assays identified antibodies against melibiose and L-rhamnose as mediators of anti-hamster and anti-porcine xenoantibody cross-reactivity with E. faecalis. A rise in TI anti-hamster and anti-pig xenoantibodies was accompanied by decreased survival of Lewis rats in a low-severity sepsis model of CLP. Therefore, TI xenoantibodies in the rat include anti-carbohydrate antibodies reactive to bacteria of endogenous flora. Enhancement of these antibodies may result in more severe infectious diseases caused by these microorganisms.