HLA-DRB1*0402 (DW10) transgene protects collagen-induced arthritis-susceptible H2Aq and DRB1*0401 (DW4) transgenic mice from arthritis

To investigate the role of HLA-DR4 in predisposition to arthritis, we generated transgenic mice carrying DRB1*0401 and DRB1*0402 genes. We have previously shown that DRB1*0401 molecule renders B10.RQB3 (H2A(q)) mice susceptible to porcine and human type II collagen-induced arthritis. We report that the introduction of DRB1*0402 transgene does not lead to development of arthritis in mice when they are immunized with porcine and human type II collagen. In addition, DRB1*0402 protects B10.RQB3 mice against developing arthritis with bovine type II collagen. These data show that DRB1 can modulate the disease mediated by A(q). In vivo depletion of DRB1*0402 did not lead to induction of collagen-induced arthritis in transgenic mice. In vitro cytokine analysis shows that mice protected from collagen-induced arthritis produce lower amounts of Th1 and higher levels of Th2 type cytokines upon immunization with type II collagen. Protection of mice was also related to higher apoptosis in DW10 mice as indicated by higher amounts of BclII in response to type II collagen. On the basis of our observations in HLA transgenic mice, we hypothesize that DRB1 polymorphism can modulate disease by shaping the T cell repertoire in thymus and select autoreactive T cells.     

Cowpea Root Rot Severity and Metabolic Changes in Relation to Manganese Application

Severity of root rot (Rhizoctonia solani and Rhizoctonia bataticola) of cowpea (Vigna unguiculata L.) was reduced by 42.7 and 42.0%, respectively over control following the application of 10 μg/g Mn as manganese sulphate. Reduction in disease incidence was associated with increased levels of polyphenol oxidase (PPO), peroxidase (PO) and total phenols. PO activity was several times more as compared with PPO‐specific activity and increased markedly after infection either with R. solani or R. bataticola. Contrary to PPO and PO, the specific activity of catalase declined sharply. Infection also caused an increase in the content of reducing sugars, Cu, Zn and Mn but a decrease in o‐dihydric phenols, flavanols, total soluble sugars, non‐reducing sugars and Fe contents. It is suggested that Mn at the rate of 10 μg/g soil can be used to manage the root rot of cowpea.     

Inosine from liver as a possible energy source for pig red blood cells

Adult pig red blood cells are unable to metabolize glucose due to a membrane permeability barrier to glucose developed shortly after birth. $\text{In}$$\text{vitro}$, pig red cells incubated in their own plasma are unable to maintain normal ATP levels, thus the question has been raised as to the nature of the metabolic energy source. We have suggested that organs, such as the liver, might supply low levels of substrate to the red cells as they transit through the organ. In this paper, evidence is presented to show that perfused pig livers supply a metabolic substrate used by pig red cells. This substrate has been tentatively identified as inosine.     

Characterization of a new sulfhydryl group reagent: 6,6′-Diselenobis-(3-Nitrobenzoic acid), a selenium analog of Ellman's reagent

A new reagent, 6,6′-diselenobis-(3-nitrobenzoic acid) (DSNB) has been synthesized and is shown to be useful for quantitative estimation of sulfhydryl groups in proteins. This reagent, which is a selenium analog of Ellman's reagent, reacts specifically and quantitatively with thiol groups of proteins to yield a selenenyl sulfide and the dianion of 3-nitro-6-selenobenzoic acid. The molar absorption coefficient of the chromophoric dianion is 10,000 at 432 nm in dilute aqueous solutions. The titration can best be performed at pH 8.20 where >98% of 3-nitro-6-selenobenzoic acid is in the form of the intensely colored dianion. Sulfhydryl content determinations by this reagent of reduced and denatured ribonuclease, reduced and denatured lysozyme, native papain, and native and denatured thymidylate synthetase are compared with those from corresponding 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) titrations. The reagent was found to inactivate thymidylate synthetase, an enzyme with essential sulfhydryl groups. Unlike DTNB which undergoes alkaline decomposition of pH values greater than 9, DSNB was found to be stable to hydrolysis, even in 0.05 m NaOH.     

Value of radiologically guided fine needle aspiration cytology (FNAC) in the diagnosis of spinal tuberculosis: a study of 29 cases

FNAC is a simple diagnostic tool for the initial evaluation of various deep seated pathological lesions. This study describes the applicability and practical aspects of the technique in establishing the diagnosis of spinal tuberculosis (TB) with the aid of radiographic guidance. The study was conducted in a major teaching hospital in Kuwait between the years 1985 and 1994. Twenty-nine patients (M:F = 18:11 and age range 8-72 years) with clinically and/or radiologically suspected spinal TB were seen in the Department of Cytology, Mubarak Al Kabeer Hospital. The patients were re-examined by either computed tomography (CT) scanning (n = 19) or fluoroscopy (n = 10) to localize the lesion for FNAC. FNAC smears were routinely stained with Papanicolaou and Diff Quik stains and one smear of each case was stained with Ziehl-Neelsen (Z-N) stain for acid-fast bacilli (AFB). Aspirated purulent material or syringe washings of dry aspirates were also submitted for microbiological cultures including AFB. Radiological and cytological findings were recorded in each case. Radiological findings included: bony rarefaction and destruction (93.1%), narrowed disc space (89.7%), soft tissue calcification (65.5%) and para-vertebral abscess formation (51.7%). Cytological findings included: epithelioid cell granulomas (89.7%), granular necrotic background (82.8%) and lymphocytic infiltration (75.9%). Smears were positive for AFB in 51.7% of cases. A positive AFB culture was obtained in 82.8% of cases, including all cases with positive AFB on smear by Z-N stain. Radiologically guided FNAC with AFB culture is a simple, reliable and practical approach to diagnosing spinal TB lesions. With a high diagnostic yield, it allows immediate initiation of specific treatment, helps to avoid invasive diagnostic procedures, and decreases hospitalization time.     

Proliferating cell nuclear antigen (PCNA) as a proliferative marker during embryonic and adult zebrafish hematopoiesis

We investigated the expression of proliferative cell nuclear antigen (PCNA) in zebrafish to delineate the proliferative hematopoietic component during adult and embryonic hematopoiesis. Immunostaining for PCNA and enhanced green fluorescence protein (eGFP) was performed in wild-type and fli1-eGFP (endothelial marker) and gata1-eGFP (erythroid cell marker) transgenic fish. Expression of PCNA mRNA was examined in wild-type and chordin morphant embryos. In adult zebrafish kidney, the renal tubules are surrounded by endothelial cells and it is separated into hematopoietic and excretory compartments. PCNA was expressed in hematopoietic progenitor cells but not in mature neutrophils, eosinophils or erythroid cells. Some PCNA+ cells are scattered in the hematopoietic compartment of the kidney while others are closely associated with renal tubular cells. PCNA was also expressed in spermatogonial stem cells and intestine crypts, consistent with its role in cell proliferation and DNA synthesis. In embryos, PCNA is expressed in the brain, spinal cord and intermediate cell mass (ICM) at 24 h-post fertilization. In chordin morphants, PCNA is significantly upregulated in the expanded ICM. Therefore, PCNA can be used to mark cell proliferation in zebrafish hematopoietic tissues and to identify a population of progenitor cells whose significance would have to be further investigated.     

HLA-DR modulates autoantibody repertoire, but not mortality, in a humanized mouse model of systemic lupus erythematosus

To evaluate the disease-modulating role of HLA-DR2 and DR3 molecules, which have been associated with systemic lupus erythematosus, a humanized mouse model was examined. HLA-DR2 (DRB1*1502)- and DR3 (DRB1*0301)-transgenic mice were backcrossed to the New Zealand Mixed 2410 (NZM 2410, H2(z)) strain. Seventh generation DR2 and DR3 transgene-positive animals along with their transgene-negative littermates and the parental strain NZM2410 were monitored for proteinuria, azotemia, autoantibody production, development of nephritis, and mortality. The results showed no significant differences in proteinuria, azotemia, or mortality between the backcrosses with and without HLA-DR2 or HLA-DR3. However, the genetic analysis of different backcrosses showed that heterozygosity at the endogenous H2-E locus (E(z)/E(b)) was strongly linked with acceleration of lupus nephritis in both HLA-DR2 and HLA-DR3 transgenics. More importantly, the presence of the HLA-DR2, but not the HLA-DR3, transgene significantly enhanced the production of anti-dsDNA, but not anti-ssDNA, anti-histone-dsDNA complex, or anti-histone, Abs. In contrast, neither HLA-DR2 nor HLA-DR3 influenced the development of glomerulonephritis or the degree of immune complex deposition. Moreover, nephritic kidneys from mice with and without HLA-DR2 or HLA-DR3 transgenes showed similar patterns of cytokine expression. Collectively, these findings provide molecular evidence that the association of HLA-DR2 or HLA-DR3 with lupus susceptibility is related to the type of autoantibody rather than to disease mortality. The use of a humanized mouse model provides a way of dissecting the roles of human MHC genes in systemic lupus erythematosus pathogenesis.     

Cross-neutralization of SARS-CoV-2 by HIV-1 specific broadly neutralizing antibodies and polyclonal plasma

Cross-reactive epitopes (CREs) are similar epitopes on viruses that are recognized or neutralized by same antibodies. The S protein of SARS-CoV-2, similar to type I fusion proteins of viruses such as HIV-1 envelope (Env) and influenza hemagglutinin, is heavily glycosylated. Viral Env glycans, though host derived, are distinctly processed and thereby recognized or accommodated during antibody responses. In recent years, highly potent and/or broadly neutralizing human monoclonal antibodies (bnAbs) that are generated in chronic HIV-1 infections have been defined. These bnAbs exhibit atypical features such as extensive somatic hypermutations, long complementary determining region (CDR) lengths, tyrosine sulfation and presence of insertions/deletions, enabling them to effectively neutralize diverse HIV-1 viruses despite extensive variations within the core epitopes they recognize. As some of the HIV-1 bnAbs have evolved to recognize the dense viral glycans and cross-reactive epitopes (CREs), we assessed if these bnAbs cross-react with SARS-CoV-2. Several HIV-1 bnAbs showed cross-reactivity with SARS-CoV-2 while one HIV-1 CD4 binding site bnAb, N6, neutralized SARS-CoV-2. Furthermore, neutralizing plasma antibodies of chronically HIV-1 infected children showed cross neutralizing activity against SARS-CoV-2 pseudoviruses. Collectively, our observations suggest that human monoclonal antibodies tolerating extensive epitope variability can be leveraged to neutralize pathogens with related antigenic profile.     

Current updates on precision therapy for breast cancer associated brain metastasis: Emphasis on combination therapy

Molecular and Cellular Biochemistry - Cancer therapies have undergone a tremendous progress over the past decade. Precision medicine provides a more tailored approach, making the combination of...