Antigen-specific memory Th17 cells promote cross-protection against nontypeable Haemophilus influenzae after mild influenza A virus infection.

Secondary bacterial pneumonia after influenza A virus (IAV) infection is the leading cause of hospitalization and death associated with IAV infection worldwide. Nontypeable Haemophilus influenzae (NTHi) is one of the most common causes of secondary bacterial pneumonia. Current efforts to develop vaccines against NTHi infection focus on inducing antibodies but are hindered by antigenic diversity among NTHi strains. Therefore, we investigated the contribution of the memory T helper type 17 (Th17) response in protective immunity against IAV/NTHi coinfection. We observed that even a mild IAV infection impaired the NTHi-specific Th17 response and increased morbidity and mortality compared with NTHi monoinfected mice. However, pre-existing memory NTHi-specific Th17 cells induced by a previous NTHi infection overcame IAV-driven Th17 inhibition and were cross-protective against different NTHi strains. Last, mice immunized with a NTHi protein that induced a strong Th17 memory response were broadly protected against diverse NTHi strains after challenge with coinfection. These results indicate that vaccination that limits IAV infection to mild disease may be insufficient to eliminate the risk of a lethal secondary bacterial pneumonia. However, NTHi-specific memory Th17 cells provide serotype-independent protection despite an ongoing IAV infection and demonstrate the advantage of developing broadly protective Th17-inducing vaccines against secondary bacterial pneumonia.

Hepatitis reactivation in patients with rheumatic diseases after immunosuppressive therapy--a report of long-term follow-up of serial cases and literature review.

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.

Efficacy and safety of live attenuated persistent and rapidly cleared Mycobacterium tuberculosis vaccine candidates in non-human primates.

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 mc(2)6020 (DeltalysA DeltapanCD) and mc(2)6030 (DeltaRD1 DeltapanCD) in cynomolgus macaques. In murine models, mc(2)6020 is rapidly cleared while mc(2)6030 persists. Both mc(2)6020 and mc(2)6030 were safe and well tolerated in cynomolgus macaques. Following a high-dose intrabronchial challenge with virulent M. tuberculosis, mc(2)6020-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 mc(2)6030 vaccinates, but survival did not differ among the groups.

Novel recombinant RD2- and RD11-encoded Mycobacterium tuberculosis antigens are potential candidates for diagnosis of tuberculosis infections in BCG-vaccinated individuals.

Proteins encoded by region of deletions (RD) of Mycobacterium tuberculosis are useful in development of vaccines and diagnostic reagents. In the present study, six M. tuberculosis genes from RD2 and RD11, rv1978, nrdf1, mpt64, cfp-21, ppe57 and ppe59, were cloned and overexpressed in Escherichia coli. All six purified recombinant proteins could distinguish tuberculosis (TB) patients and latent TB infected subjects (LTBI), or called subclinical TB infection, from BCG-vaccinated healthy controls by T-cell IFN-gamma releasing ELISPOT. ELISPOT of Rv1978, NrdF1, Mpt64, CFP-21, Ppe57 and Ppe59 achieved sensitivities of 59%, 60%, 82%, 48%, 59% and 47% respectively in the detection of active TB and specificities of 94%, 90%, 76%, 93%, 100% and 93% respectively in BCG-vaccinated healthy controls. Combination of Ppe57 or NrdF1 with early secreted antigen target 6 (ESAT-6) or 10-kDa culture filtrate protein (CFP-10) in the IFN-gamma releasing ESLIPOT assay could increase the sensitivities in detecting active TB, for ESAT-6 from 82.1% to 85.7% or 92.9% (P=0.5 or 0.03, respectively) and for CFP-10 from 67.9% to 78.6% or 83.9%, respectively (both P<0.05). The high sensitivities, specificities and promising antigenic combination of NrdF1 and Ppe57 in detection of TB in BCG-vaccinated controls suggest their potential application in TB diagnosis.

Coadministration of cidofovir and smallpox vaccine reduced vaccination side effects but interfered with vaccine-elicited immune responses and immunity to monkeypox.

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.

Variants of the natural resistance-associated macrophage protein 1 gene (NRAMP1) are associated with severe forms of pulmonary tuberculosis.

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.