Tuberculosis (TB) remains a global health burden for which safe vaccines are needed. BCG has limitations as a TB vaccine so we have focused on live attenuated Mycobacterium tuberculosis mutants as vaccine candidates. Prior to human studies, however, it is necessary to demonstrate safety in non-human primates (NHP). In this study, we evaluate the safety and efficacy of two live attenuated M. tuberculosis double deletion vaccine strains mc26020 (ΔlysA ΔpanCD) and mc26030 (ΔRD1 ΔpanCD) in cynomolgus macaques. In murine models, mc26020 is rapidly cleared while mc26030 persists. Both mc26020 and mc26030 were safe and well tolerated in cynomolgus macaques. Following a high-dose intrabronchial challenge with virulent M. tuberculosis, mc26020-vaccinates were afforded a level of protection intermediate between that elicited by BCG vaccination and no vaccination. BCG vaccinates had reduced tuberculosis-associated pathology and improved clinical scores as compared to saline and mc26030 vaccinates, but survival did not differ among the groups.

Although genetic factors may affect susceptibility to tuberculosis, studies that have assessed variants of the natural resistance-associated macrophage protein 1 gene (NRAMP1) and their association with tuberculosis in humans have yielded conflicting results. It is likely that NRAMP1 polymorphisms may be associated with progression to severe forms of pulmonary tuberculosis rather than with susceptibility to Mycobacterium tuberculosis infection. To test this possibility, we examined NRAMP1 variants at the INT4 and D543N loci, as well as their association with severe forms of pulmonary tuberculosis, in 127 patients with active pulmonary tuberculosis and in 91 ethnically matched, healthy control subjects in areas of China where tuberculosis is endemic. We found that NRAMP1 polymorphisms at these 2 loci were significantly associated with 2 severe forms of pulmonary tuberculosis: sputum smear-positive tuberculosis and cavitary tuberculosis. The NRAMP1 variants were not associated with pulmonary M. tuberculosis infection, when analyses of all patients with tuberculosis and all control subjects were performed. The findings of the present study support the hypothesis that genetic variants of NRAMP1 may have an effect on bacilli growth and on outcomes of pulmonary tuberculosis, but not on susceptibility to M. tuberculosis infection.

The aims of this paper are to report hepatitis B virus reactivation in 12 patients with rheumatic disease undergoing immunosuppressive therapy and to evaluate whether pre-emptive antiviral therapy is necessary in patients receiving disease-modifying anti-rheumatic drugs. From January 2008 to March 2012, a total of 12 HBV-infected patients with rheumatic diseases were consecutively enrolled in the long-term follow-up. Liver function, HBV DNA, and serum aminotransferase level were tested during the follow-up. We also reviewed the published reports and summarized the clinical characteristics of HBV reactivation during immunosuppressive therapy in patients with rheumatic diseases. The medium duration of follow-up was 41 months (range 16–48). Patients were treated with prednisone, disease-modifying anti-rheumatic drugs (DMARDs) or tumor necrosis factor-alpha-blocking agents (TNFBA). HBV reactivation was only documented in two patients treated with prednisone without pre-emptive antiviral therapy. One hundred patients from literature review were identified as having HBV reactivation; 20.8 % of the patients receiving prednisone experienced HBV reactivation compared to only 4.46 and 9.52 % of patients treated with DMARDs or TNFBA, respectively. This long-term follow-up of serial cases suggests that pre-emptive antiviral therapy should be administered in patients receiving prednisone therapy for rheumatic disease. In contrast, DMARDs and TNFBA are relatively safe to HBV-infected patients with rheumatic diseases. Close monitoring of HBV DNA and ALT levels is necessary in the management of HBV reactivation.

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While the smallpox vaccine, Dryvax or Dryvax-derived ACAM2000, holds potential for public immunization against the spread of smallpox by bioterror, there is serious concern about Dryvax-mediated side effects. Here, we report that a single-dose vaccination regimen comprised of Dryvax and an antiviral agent, cidofovir, could reduce vaccinia viral loads after vaccination and significantly control Dryvax vaccination side effects. However, coadministration of cidofovir and Dryvax also reduced vaccine-elicited immune responses of antibody and T effector cells despite the fact that the reduced priming could be boosted as a recall response after monkeypox virus challenge. Evaluations of four different aspects of vaccine efficacy showed that coadministration of cidofovir and Dryvax compromised the Dryvax-induced immunity against monkeypox, although the covaccinated monkeys exhibited measurable protection against monkeypox compared to that of naïve controls. Thus, the single-dose coadministration of cidofovir and Dryvax effectively controlled vaccination side effects but significantly compromised vaccine-elicited immune responses and vaccine-induced immunity to monkeypox.

Mycobacterium tuberculosis KatG enzyme functions both as catalase for removing hydrogen peroxide (H 2 O 2 ) and as peroxidase for oxidating isoniazid (INH) to active form of anti-tuberculosis drug. Although mutations in M. tuberculosis KatG confer INH resistance in tuberculous patients, structural bases for INH-resistant mutations in the KatG gene remains poorly understood. Here, three M. tuberculosis KatG mutants bearing Arg418→ Gln, Ser315 → Thr, or Trp321 → Gly replacement were assessed for changes in catalase-peroxidase activities and possible structure bases relevant to such changes. These three M. tuberculosis KatG mutants exhibited a marked impairment or loss of catalase-peroxidase activities. The possible structural bases for the mutant-induced loss of enzyme activities were then analyzed using a three-dimensional model of M. tuberculosis KatG protein constructed on the basis of the crystal structure of the catalase-peroxidase from Burkholderia pseudomallei. The model suggests that three M. tuberculosis KatG mutants bearing Arg418 → Gln, Ser315 → Thr, or Trp321 → Gly replacement affect enzyme activities by different mechanisms, although each of them impacts consequently on a heme-associated structure, the putative oxidative site. Moreover, in addition to the widely accepted substrate-binding site, M. tuberculosis KatG may bear another H 2 O 2 binding site. This H 2 O 2 binding site appears to interact with the catalytic site by a possible electron-transfer chain, a Met255-Tyr229-Trp107 triad conserved in many catalaseperoxidases. The Ser315 → Thr mutant may have direct effect on the catalytic site by interfering with electron transfer in addition to the previously proposed mechanism of steric constraint.

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