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Abstract The electric dipoles of proteins in a biolayer determine their dielectric properties through the polarization density P. Hence, its reproducibility is crucial for applications, particularly in bioelectronics. Biolayers encompassing capturing antibodies covalently bound at a biosensing interface are generally preferred for their assumed higher stability. However, surface physisorption is shown to offer advantages like easily scalable fabrication processes and high stability. The present study investigates the effects of electric‐field (EF)‐cycling of anti‐Immunoglobulin M (anti‐IgM) biolayers physisorbed on Au. The impact of EF‐cycling on the dielectric, optical, and mechanical properties of anti‐IgM biolayer is investigated. A reduction of the dispersion (standard deviation over a set of 31 samples) of the measured P values is observed, while the set median stays almost constant. Hence, physisorption combined with EF cycling, results in a biolayer with highly reproducible bioelectronic properties. Additionally, the study provides important insights into the mechanisms of dielectric rearrangement of dipole moments in capturing biolayers after EF‐cycling. Notably, EF‐cycling acts as an annealing process, driving the proteins in the biolayer into a statistically more probable and stable conformational state. Understanding these phenomena enhances the knowledge of the properties of physisorbed biolayers and can inform design strategies for bioelectronic devices.

Influenza A (H1N1) virus is now rapidly scattering across the world. Early detection is one of the most effective measures to stop the further spread of the virus. The current study was aimed to detect influenza A (H1N1) serologically and by polymerase chain reaction (PCR) techniques. From September 2020 to June 2021, three hundred nasopharyngeal swabs and blood samples were collected from Hiwa and Shahid Tahir Hospitals in Sulaimani city. Obtained results revealed that 23.3% of the tested patients were seropositive anti-IgG for Influenza A, while 13.3% showed anti-IgM seropositive results although 10% of the tested cases were with both anti-IgG and anti-IgM seropositive results. Gender, residency, and flu symptoms showed no significant relations with seropositive results (p<0.05) whereas valuable relations were found between seropositive observations and smoking, the previous history of chronic diseases as well as employment status (p<0.05). It was concluded that hematologic investigations (CBC) were not dependable if H1N1 diagnosis and detection. Only 1% of the tested samples showed positive results for influenza A (H1N1) RNA using reverse transcription-PCR. [ABSTRACT FROM AUTHOR]

Background Anti-M is most often assumed to be naturally occurring and can be comprised of a mixture of predominantly immunoglobulin(Ig)M with a lesser IgG component. Anti-M-antibodies usually do not react at 37°C and therefore are considered to be of little clinical significance. Methods A 28-year-old man presented with hemorrhagic shock from numerous injuries sustained in a motor vehicle collision. The patient received several units of red blood cells (RBCs). The antibody screen, the direct antiglobulin test (DAT), and the RBC genotype were sent for laboratory evaluation. Results A total of 12 days after the first antibody screening result was negative (7 days after transfusion), the lowest hemoglobin value was 5.5 g per dL, and we observed a positive antibody screening result and DAT with immunoglobulin (Ig)G anti-M identified. After transfusion of 4 units of M antigen–negative RBC, the post-transfusion hemoglobin level increased to 8.9 g per dL. Conclusion Obtaining M antigen–negative compatible RBCs is necessary in patients demonstrating IgG anti-M in plasma. [ABSTRACT FROM AUTHOR]

The selection and maturation of B-cell clones are critically determined by tonic signals from activated B cell receptors (BCR) and survival signals from BAFF cytokine. These finely tuned and coordinated signals provide a net positive signal that can promote the selection, maturation, proliferation and differentiation of a developing B cell. Stimulation with an anti-IgD antibody can also activate BCR but can lead to depletion and an arrest of mature B-cell development in vivo. It is not known whether survival signals from excess BAFF can override the suppressive effects of treatment with anti-IgD on mature B cells in vivo. Herein, we examined the effects of co-treatment of BAFF and anti-IgD on the mature B-cell compartment and antibody production in vivo by treating mice with either 1 mg/kg BAFF or anti-IgD alone or in combination for 3 consecutive days. We found that co-treatment with anti-IgD significantly abrogated these stimulatory effects of BAFF treatment on splenic CD19+ B cells as well as mature CD19+IgDhiIgM+ B cells in vivo. Anti-IgD down-regulated the expression of the BCR complex (mIgM, mIgD and CD19) and the BAFF receptor TACI without regard to the presence of BAFF. Anti-IgD treatment also significantly negated BAFF-induced IgM production in vivo. Both BAFF and anti-IgD could individually stimulate IL-10 synthesis in B cells but did not affect one another. Taken together, our data suggest that activation of BCR with an anti-IgD antibody can override the stimulatory effects from excess BAFF on B cell proliferation and antibody production by down-regulating the expression of BCR complex and BAFF receptors. [ABSTRACT FROM AUTHOR]

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To evaluate the dependence of the differentiation of the follicle-associated epithelium (FAE) on the presence of follicular B-cells, the FAE of ileal Peyer’s patch follicles was examined in B-cell-depleted fetal lambs. The FAE of these rudimentary follicles, which are devoid of lymphocytes, showed normal differentiation, including carbonic anhydrase reactivity and ultrastructural characteristics of transcytosis, extensive interdigitation of the lateral plasma membrane and the shedding of membrane-bounded particles, approximately 50 nm in size, resembling exosomes. These 50-nm membrane-bounded particles were abundant in the extracellular space of the epithelium and the dome but no particles were found in the rudimentary follicles. This study confirms that the rudimentary follicles consist of clusters of follicular dendritic cells. Our findings suggest that the differentiation of FAE of ileal Peyer’s patch and the production of the 50-nm particles constitute features that appear to be independent of B-cells. [ABSTRACT FROM AUTHOR]

Apoptosis of lymphocytes recognizing self-antigens is an essential mechanism to protect the organism against autoimmune diseases. Programmed cell death of susceptible B cells occurs in response to surface IgM cross-linking mediated by self-antigens. This effect can be mimicked in the Burkitt''s lymphoma line BL60-2 by addition of anti-IgM antibodies. In order to identify genes with differential expression in response to the apoptotic stimulus, total RNA prepared from BL60-2 cells before and at different points in time after IgM cross-linking was used for Atlas arrays, high-density oligonucleotide microarrays (GeneChip arrays, Affymetrix) and in RNase protection assays (RPA). One of our major observations was the downregulation of six genes involved in the ligation of DNA strand breaks, like DNA ligases and DNA-PK, indicating a shutdown of DNA repair mechanisms in apoptotic cells. In addition, we found changes on mRNA level for several transcription regulators, including early growth response genes 1 and 2, TAFII30 and topoisomerase I. Furthermore, we show accumulation of mRNA for the phosphatases CD45 and DUSP5 in anti-IgM stimulated BL60-2 cells. Our data provide a basis for further analysis of the differentially expressed genes and their roles in IgM-induced B cell death as well as in apoptosis in other cellular systems. [Copyright &y& Elsevier]

Summary. In previous studies, we demonstrated an over-expression of the dominant-negative isoform of the transcription factor Ikaros, Ik-6, in patients with B-cell malignancies, including blast crisis of chronic myelogenous leukaemia and acute lymphoblastic leukaemia. To investigate the consequence of over-expression of Ik-6 in B cells, we constructed Ik-6 transfectants of the FDH-1 and Ramos cell lines. FDH-1, which was established from a patient with early pre-B acute lymphoblastic leukaemia, undergoes apoptosis with dexamethasone treatment, whereas Ramos undergoes apoptosis following anti-IgM antibody treatment. Compared with the wild type, the over-expression of Ik-6 rendered the FDH-1 and Ramos transfectants resistant to dexamethasone-induced and anti-IgM-induced apoptosis respectively. An immunoblotting study demonstrated bcl-2 upregulation in anti-IgM-induced Ramos Ik-6 transfectants, but not in FDH-1 Ik-6 transfectants. Further investigations of the mechanism of leukaemogenesis associated with the over-expression of Ik-6 are warranted. [ABSTRACT FROM AUTHOR]

The administration of a single bolus of anti-IgM antibody to foetal lambs early in pregnancy produces prolonged B-cell depletion. The present study investigated this depletion by examining the effect, on B-cell development in the ileal Peyer's patches, of varying the timing and dosage of antibody administration and by supplementing anti-IgM with surgical splenectomy. The capacity of a 1 mg bolus of anti-IgM to deplete Peyer's patches of B cells was lost if its administration was deferred until two thirds of the way through pregnancy, but persisted beyond this time if weight-adjusted doses were used. Splenectomy of the foetus performed at an earlier age failed to extend the age at which a 1 mg dose of antibody remained effective. As the concentration of murine immunoglobulin in foetal serum was greatly reduced after 21 days, it is inferred that ongoing suppression of B-cell development is not dependent on the continued presence of murine immunoglobulin. The enduring nature of suppression could be attributable to a limited period during which differentiation of B cells from stem cells normally occurs, although further studies will be needed to investigate this and other possible explanations for the effect of anti-IgM treatment on prenatal B-cell development in sheep. [ABSTRACT FROM AUTHOR]

The administration of a single bolus of anti-IgM antibody to foetal lambs early in pregnancy produces prolonged B-cell depletion. The present study investigated this depletion by examining the effect, on B-cell development in the ileal Peyer's patches, of varying the timing and dosage of antibody administration and by supplementing anti-IgM with surgical splenectomy. The capacity of a 1 mg bolus of anti-IgM to deplete Peyer's patches of B cells was lost if its administration was deferred until two thirds of the way through pregnancy, but persisted beyond this time if weight-adjusted doses were used. Splenectomy of the foetus performed at an earlier age failed to extend the age at which a 1 mg dose of antibody remained effective. As the concentration of murine immunoglobulin in foetal serum was greatly reduced after 21 days, it is inferred that ongoing suppression of B-cell development is not dependent on the continued presence of murine immunoglobulin. The enduring nature of suppression could be attributable to a limited period during which differentiation of B cells from stem cells normally occurs, although further studies will be needed to investigate this and other possible explanations for the effect of anti-IgM treatment on prenatal B-cell development in sheep. [ABSTRACT FROM AUTHOR]

• MyxoTLm demonstrated to be useful for the serodiagnosis of bovine trypanosomiasis. • Anti- T. vivax IgG ELISA revealed specificity of 95,65 % and sensitivity of 88,23 %. • Anti- T. vivax IgM ELISA revealed specificity of 91,30 % and sensitivity of 82,35 %. • MyxoTLm increase the sensitivity and the specificity if compared to crude antigens. Human trypanosomiases and animal trypanosomoses are caused by distinct protozoan parasites of the genus Trypanosoma. The etiological agents of bovine trypanosomosis (BT) are T. vivax , T. congolense , or T. brucei , whose acute infections are initially characterized by hyperthermia, following moderate to severe anemia, subcutaneous edema, lethargy, reduced milk production, progressive weight loss, enlarged lymph nodes, reproductive disorders and death. Animals that survive the acute phase might recover and progress to the chronic, often asymptomatic, phase of infection. Despite their low sensitivity due to the characteristic low parasitemia, simple and costless direct parasitological examinations are the preferred diagnostic methods for animals. Thus, most of the epidemiological studies of BT are based on serological techniques using crude antigen. In this study, we describe the use of the MyxoTLm recombinant protein as an antigen on serological assays. Anti- T. vivax IgM and anti- T. vivax IgG ELISA assays using purified MyxoTLm revealed specificity rates of 91.30 % and 95.65 % and sensitivity rates of 82.35 % and 88.23 %, respectively, being higher than reported for crude antigens. Also, MyxoTLm demonstrated a good performance to detect IgM (ROC curve area = 0.8568) and excellent performance to detect IgG (ROC curve area = 0.9565) when compared to a crude antigen. T. evansi crude antigen used in the indirect anti- T. vivax IgM ELISA reached 70.58 % sensitivity and 78.26 % specificity, and had a lower test performance (ROC curve area = 0.7363). When applied to the anti- T. vivax IgG ELISA, the crude antigen reached 82.35 % sensitivity and 69.56 % specificity, also presenting a low performance with area under the ROC curve of 0.7570. Therefore, the use of MyxoTLm as an antigen on serological diagnosis of BT revealed to increase the sensitivity and the specificity if compared to crude antigens. [ABSTRACT FROM AUTHOR]

Intravital two-photon laser scanning microscopy (TP-LSM) has allowed the direct observation of immune cells in intact organs of living animals. In the B cell biology field TP-LSM has detailed the movement of B cells in high endothelial venules and during their transmigration into lymph organs; described the movement and positioning of B cells within lymphoid organs; outlined the mechanisms by which antigen is delivered to B cells; observed B cell interacting with T cells, other cell types, and even with pathogens; and delineated the egress of B cells from the lymph node (LN) parenchyma into the efferent lymphatics. As the quality of TP-LSM improves and as new fluorescent probes become available additional insights into B cell behavior and function await new investigations. Yet intravital TP-LSM has some disadvantages including a lower resolution than standard confocal microscopy, a narrow imaging window, and a shallow depth of imaging. We have found that supplementing intravital TP-LSM with conventional confocal microscopy using thick LN sections helps to overcome some of these shortcomings. Here, we describe procedures for visualizing the behavior and trafficking of fluorescently labeled, adoptively transferred antigen-activated B cells within the inguinal LN of live mice using two-photon microscopy. Also, we introduce procedures for fixed thick section imaging using standard confocal microscopy, which allows imaging of fluorescently labeled cells deep in the LN cortex and in the spleen with high resolution.