Design of an epitope-based peptide vaccine against Cryptococcus neoformans.

Cryptococcus neoformans is the highest-ranked fungal pathogen in the Fungal Priority Pathogens List (FPPL) released by the World Health Organization (WHO). In this study, through in silico simulations, a multi-epitope vaccine against Cryptococcus neoformans was developed using the mannoprotein antigen (MP88) as a vaccine candidate. Following the retrieval of the MP88 protein sequences, these were used to predict antigenic B-cell and T-cell epitopes via the bepipred tool and the artificial neural network, respectively. Conserved B-cell epitopes AYSTPA, AYSTPAS, PASSNCK, and DSAYPP were identified as the most promising B-cell epitopes. While YMAADQFCL, VSYEEWMNY, and FQQRYTGTF were identified as the best candidates for CD8+ T-cell epitopes; and YARLLSLNA, ISYGTAMAV, and INQTSYARL were identified as the most promising CD4+ T-cell epitopes. The vaccine construct was modeled along with adjuvant and peptide linkers and the expasy protparam tool was used to predict the physiochemical properties. According to this, the construct vaccine was predicted to be antigenic, nontoxic, nonallergenic, soluble, stable, hydrophilic, and thermostable. Furthermore, the three-dimensional structure was also used in docking analyses with Toll-like receptor (TLR4). Finally, the cDNA of vaccine was successfully cloned into the E. coli pET-28a (+) expression vector. The results presented here could contribute towards the design of an effective vaccine against Cryptococcus neoformans.

Association between pulmonary tuberculosis and Type 2 diabetes in Sudanese patients.

INTRODUCTION: Tuberculosis (TB) and diabetes mellitus (DM) are both important health issues, and the association between DM and TB may be the next challenge for global TB control worldwide, type 2 DM (T2DM) responsible for 90% of DM cases. Persons with diabetes have a significantly increased risk of active TB, which is two to three times higher than in persons without diabetes. The aim of this study was to determine the association between pulmonary tuberculosis (PTB) and T2DM among Sudanese patients and also to determine the association between hemoglobin A1c (HbA1c) percentage in diabetic patients and development of PTB and effect of duration of T2DM in developing PTB. MATERIALS AND METHODS: A total of 120 sputum samples were collected from patients during 6 months in Ribat University Hospital, Khartoum, Sudan. Sixty of them were known type 2 diabetic patients categorized as study group and sixty were nondiabetic patients categorized as control group. Ziehl-Neelsen smear preparation and DNA were extracted from sputum for detection of Mycobacterium tuberculosis by polymerase chain reaction (PCR). RESULTS: Among the 120 sputum specimens, 72 (60%) were males and 48 (40%) were females. Fourteen (19.4%) males and 6 (12.5%) females had PTB, the difference was not statistically significant according to gender P = 0.229. According to treatment modalities, diabetic patients were treated with injectable insulin (36.7%), PCR positive was 4(33.3%) P value (0.853), oral hypoglycemic drugs (51.7%) PCR positive 7 (58.3%) P value (0.849) and dietary control (11.7%) PCR positive (1 (8.3%) P value (1.000) Were insignificant differences. The frequency of HbA1c of 58 patients with diabetes was 24 (41.4%) who had controlled DM (HbA1c level ≤ 6.5%) and 34 (58.6%) had uncontrolled DM. Of the 60 patients with diabetes, 12 had PTB with uncontrolled DM, with significant difference (P=0.000). The mean duration of diabetes mellitus was (6.92 years ± Std 6.801) and the frequency of diabetes mellitus in first 10 years was 47 (78.3%), in (11-20) years was 10 (16.7%) and in (21-30) years was 3 (5%), the PCR positive PTB showed 10(21.3%) for the first 10 years, (11-20) years was 2 (20%) and zero (0.0%) for (21-30) years, P-value (0.480) insignificant different. CONCLUSIONS: In summary, we found consistent evidence for an increased risk of TB among patients with uncontrolled DM (high-level HbA1c).

Macrophages from patients with cirrhotic ascites showed function alteration of host defense receptor.

BACKGROUND: Patients with cirrhotic ascites (PCA) are susceptible to spontaneous bacterial peritonitis (SBP) which has increased morbidity and mortality. Since some host defense aspects of peritoneal macrophages (PMф) from PCA are altered this study examined factors related to receptor-mediated phagocytosis. METHODS: Twelve PCA were studied. PMɸ were isolated from ascitic fluid (AF) samples removed from these patients. Uptake of mannose receptor (MR)-specific ligand, fluorescein isothiocyanate-mannosylated-bovine serum albumin (FITC-man-BSA), by patients' PMɸ and controls, a human monocytic cell line, was measured pre- and post-IL-4 treatment. Phagocytosis of FITC-labeled yeast particles by patients' PMɸ was measured pre- and post-IL-4 treatment. Fluorescence values were obtained using a spectrofuorometer. MRC1 gene was analyzed in blood samples from PCA and controls, healthy donors, using standard polymerase chain reaction (PCR) technique. RESULTS: Past SBP episode(s) were reported in 58.3% of patients. Mean AF volume analyzed per patient was 1.3L. PMɸ ratio in cell yield was 53.73% (SD 18.1). Mean uptake absorbance of patients' PMф was 0.0841 (SD 0.077) compared to 0.338 (SD 0.34) of controls, P = 0.023. Following IL-4 treatment absorbance increased to 0.297 (SD 0.28) in patients' PMф (P = 0.018 on paired sample t-test), and to 0.532 (SD 0.398 in controls (P = 0.053 on independent sample t-test). Mean phagocytosis absorbance of patients' PMф was 0.1250 (SD 0.032) before IL-4 treatment compared to 0.2300 (SD 0.104) after (P = 0.026). PCR analysis for MRC1 gene was negative in all PCA samples compared to positive results in all controls. CONCLUSION: Since decreased phagocytosis and MR uptake were enhanced post-IL-4 treatment MR downregulation pre-treatment is plausible. Negative PCR results for MRC1 might suggest an anomaly, but this awaits further ellucidation. These altered host defense findings are relevant to infection pathophysiology, and their relevance to SBP susceptibility in PCA is worth verifying.