Immunoproteomic discovery of novel T cell antigens from the obligate intracellular pathogen Chlamydia

Chlamydia infections cause substantial morbidity worldwide and effective prevention will depend on a vaccine. Since Chlamydia immunity is T cell-mediated, a major impediment to developing a molecular vaccine has been the difficulty in identifying relevant T cell Ags. In this study, we used a combination of affinity chromatography and tandem mass spectrometry to identify 13 Chlamydia peptides among 331 self-peptides presented by MHC class II (I-A(b)) molecules from bone marrow-derived murine dendritic cells infected with Chlamydia muridarum. These MHC class II-bound peptides were recognized by Chlamydia-specific CD4 T cells harvested from immune mice and adoptive transfer of dendritic cells pulsed ex vivo with the peptides partially protected mice against intranasal and genital tract Chlamydia infection. The results provide evidence for lead vaccine candidates for a T cell-based subunit molecular vaccine against Chlamydia infection suitable for human study.     

Is Knowledge Regarding Tuberculosis Associated with Stigmatising and Discriminating Attitudes of General Population towards Tuberculosis Patients? Findings from a Community Based Survey in 30 Districts of India

Background

Stigmatising and discriminating attitudes may discourage tuberculosis (TB) patients from actively seeking medical care, hide their disease status, and discontinue treatment. It is expected that appropriate knowledge regarding TB should remove stigmatising and discriminating attitudes. In this study we assessed the prevalence of stigmatising and discriminating attitudes towards TB patients among general population and their association with knowledge regarding TB.

Method

A cross-sectional knowledge, attitude and practice survey was conducted in 30 districts of India in January-March 2011. A total of 4562 respondents from general population were interviewed using semi-structured questionnaires which contained items to measure stigma, discrimination and knowledge on TB.

Result

Of the 4562 interviewed, 3823 were eligible for the current analysis. Of these, 73% (95% CI 71.4–74.2) had stigmatising and 98% (95% CI 97.4–98.3) had discriminating attitude towards TB patients. Only 17% (95% CI 15.6–18.0) of the respondents had appropriate knowledge regarding TB with even lower levels observed amongst females, rural areas and respondents from low income groups. Surprisingly stigmatising (adjusted OR 1.31 (0.78–2.18) and discriminating (adjusted OR 0.79 (0.43–1.44) attitudes were independent of knowledge regarding TB.

Conclusion

Stigmatising and discriminating attitudes towards TB patients remain high among the general population in India. Since these attitudes were independent of the knowledge regarding TB, it is possible that the current disseminated knowledge regarding TB which is mainly from a medical perspective may not be adequately addressing the factors that lead to stigma and discrimination towards TB patients. Therefore, there is an urgent need to review the messages and strategies currently used for disseminating knowledge regarding TB among general population and revise them appropriately. The disseminated knowledge should include medical, psycho-social and economic aspects of TB that not only informs people about medical aspects of TB disease, but also removes stigma and discrimination.     

Targeted destruction of DNA replication protein Cdc6 by cell death pathways in mammals and yeast

The highly conserved Cdc6 protein is required for initiation of eukaryotic DNA replication and, in yeast and Xenopus, for the coupling of DNA replication to mitosis. Herein, we show that human Cdc6 is rapidly destroyed by a p53-independent, proteasome-, and ubiquitin-dependent pathway during early stages of programmed cell death induced by the DNA-damaging drug adozelesin, or by a separate caspase-dependent pathway in cells undergoing apoptosis through an extrinsic pathway induced by tumor necrosis factor-alpha and cycloheximide. The proteasome-dependent pathway induced by adozelesin is conserved in the budding yeast Saccharomyces cerevisiae. The destruction of Cdc6 may be a primordial programmed death response that uncouples DNA replication from the cell division cycle, which is reinforced in metazoans by the evolution of caspases and p53.     

Clenbuterol treatment stimulates cell proliferation in denervated chick gastrocnemius muscle

Daily administration of clenbuterol, a beta adrenoceptor agonist (0.5 mg/kg body weight; for 7 days) to normal innervated and denervated adult chicks (Gallus domesticus) resulted in different growth related responses by gastrocnemius muscle. While normal innervated muscle undergoes hypertrophy, structural reorganization in denervated tissue is accomplished by the de novo emergence of new cells. A contrasting cell population with extremely narrow cross sectional dimensions is a characteristic feature of denervated muscle in presence of clenbuterol. Measurement of fiber dimensions, number of cells per unit area and examination of histochemical preparations support this.     

A novel low molecular weight alanine aminotransferase from fasted rat liver

Alanine is the most effective precursor for gluconeogenesis among amino acids, and the initial reaction is catalyzed by alanine aminotransferase (AlaAT). Although the enzyme activity increases during fasting, this effect has not been studied extensively. The present study describes the purification and characterization of an isoform of AlaAT from rat liver under fasting. The molecular mass of the enzyme is 17.7 kD with an isoelectric point of 4.2; glutamine is the N-terminal residue. The enzyme showed narrow substrate specificity for L-alanine with K_m values for alanine of 0.51 mM and for 2-oxoglutarate of 0.12 mM. The enzyme is a glycoprotein. Spectroscopic and inhibition studies showed that pyridoxal phosphate (PLP) and free-SH groups are involved in the enzymatic catalysis. PLP activated the enzyme with a K_m of 0.057 mM.     

A novel low molecular weight alanine aminotransferase from fasted rat liver

Alanine is the most effective precursor for gluconeogenesis among amino acids, and the initial reaction is catalyzed by alanine aminotransferase (AlaAT). Although the enzyme activity increases during fasting, this effect has not been studied extensively. The present study describes the purification and characterization of an isoform of AlaAT from rat liver under fasting. The molecular mass of the enzyme is 17.7 kD with an isoelectric point of 4.2; glutamine is the N-terminal residue. The enzyme showed narrow substrate specificity for L-alanine with Km values for alanine of 0.51 mM and for 2-oxoglutarate of 0.12 mM. The enzyme is a glycoprotein. Spectroscopic and inhibition studies showed that pyridoxal phosphate (PLP) and free -SH groups are involved in the enzymatic catalysis. PLP activated the enzyme with a Km of 0.057 mM.     

A novel synthesis of 2-arylbenzimidazoles in molecular sieves-MeOH system and their antitubercular activity

Arylbenzimidazoles have been synthesized as antimycobacterial agents. An efficient synthesis has been developed for 2-arylbenzimidazoles from o-phenylenediamines and aromatic aldehydes in molecular sieves-methanol system. The methodology is straightforward to get 2-arylbenzimidazoles (3a–3z) in excellent yields with high chemoselectivity over 2-aryl-1-benzylbenzimidazoles (4a–4z). All these benzimidazole analogues were evaluated against M. tuberculosis in BACTEC radiometric assay. The compounds 4y and 4z exhibited potential antitubercular activity against M. tuberculosis H₃₇R_V, MIC at 16?µM and 24?µM respectively. The best compound of the series i.e. compound 4y was well tolerated by Swiss-albino mice in acute oral toxicity. Compound 4y possessing a diarylbenzimidazole core, can further be optimized for better activity.