Innate Signaling Pathways in the Maintenance of Serological Memory: A Dissertation

Long-term antiviral antibody responses provide protection from re-infection and recurrence of persistent viruses. Using a polyomavirus (PyV) mouse model, our lab has shown that MyD88-deficient mice generate low levels of virus-specific IgG after the acute phase of infection and that these IgG responses have a skewed isotype distribution with low levels of IgG2a/c. Moreover MyD88-deficient mice have reduced numbers of long-lived plasma cells in the bone marrow. These studies suggest an important role of MyD88-mediated signaling in long-term antiviral responses. Our lab has shown that T cell-deficient mice can also maintain long-term virus-specific IgG responses following PyV infection. The goal of this thesis is to evaluate the role of innate signaling pathways in maintaining serological memory to persistent virus infection and to elaborate on how long-term antiviral responses can be maintained in an immunocompetent or partially immune compromised, T cell-deficient host. Regarding T cell-dependent B cell responses, I set out to investigate the upstream and downstream components of the MyD88-mediated pathways required for normal antibody isotype and long-term humoral responses. IgG2a is a predominant immunoglobulin isotype in most virus infections. Wild type mice, in response to PyV infection, primarily induce antiviral IgG2a with some IgG1. MyD88-deficient mice in response to PyV infection display attenuated levels of virus-specific IgG2a, but normal levels of IgG1. Using Unc93B1 mutant mice (3d mice), which are defective in TLRs 3, 7 and 9 signaling, I show that 3d mice also generated low levels of virus-specific IgG2a following PyV infection. Studies in individual TLR3-/-, TLR7-/- or TLR9-/- mice displayed PyV-specific IgG2a responses similar to wild type responses. TLR7 and TLR9 double deficient mice generated similar skewed antibody isotype responses, where virus-specific IgG2a was reduced compared to wild type mice. This shows that TLR7 and TLR9-MyD88 mediated pathways are important in regulating IgG2a responses during a PyV infection. To investigate what components downstream of MyD88 are involved in mediating IgG2a responses, I worked with IRF5-deficient mice. IRF5 is a transcription factor that is activated upon stimulation of TLR7 or TLR9-MyD88-mediated pathways. Moreover, IRF5-deficient mice cannot generate autoantibodies specifically of the IgG2a isotype in a mouse lupus model, suggesting that IRF5 plays an important function in mediating class switching to IgG2a. In vitro studies where IRF5-/- B cells were stimulated with TLR7 or TLR9 ligands also generated low levels of γ2a germ-line transcripts, suggesting a B cell-intrinsic role for IRF5 in regulating γ2a germ-line transcription. PyV infection of IRF5-deficient mice resulted in similar skewed isotypes as observed in MyD88-deficient and 3d mice. To investigate a B cell-intrinsic role for IRF5 in regulating IgG2a responses in vivo upon PyV infection, I transferred IRF5-/- B cells and WT T cells into RAG KO mice prior to infection and compared the responses of these mice with mice reconstituted with wild type B6 B and T cells. Diminished numbers of IgG2a+ B cells and reduced levels of virus-specific IgG in mice reconstituted with IRF5-/- B cells were seen compared to mice reconstituted with wild type B cells. Regarding the defect in long-term IgG production in MyD88-/- mice upon PyV infection, I conducted studies in IRF5-/-, 3d, single TLR3-/-, TLR7-/-, TLR9-/- and TLR7/9 double deficient mice. These studies reveal an important and redundant role for TLR7- and TLR9-MyD88 signaling in maintaining long-term anti-PyV IgG responses. To determine how MyD88 signaling affects the generation of long-lived plasma cells and memory B cells, I investigated germinal center (GC) responses in MyD88-deficient mice. A defect in GC B cell numbers is observed in MyD88-deficient mice after the acute phase of infection. The GC reaction is essential for the generation and maintenance of long-lived plasma cells and memory B cells. T follicular helper (TFH) cells are absolutely required to generate normal GC. l found reduced numbers of TFH cells in MyD88-deficient mice. Lower numbers of T FH cells suggests that poor T cell help may contribute to the diminished number of GC B cells. However, interaction with B cells is required for the formation of fully differentiated TFH cells. Along with B cell function, MyD88 signaling can affect T cell and dendritic cell function as well. Thus, it is not clear at this point whether the requirement for intact MyD88 signaling for the formation and maintenance of long-term B cell populations is completely B cell-intrinsic. Some viruses can induce T cell-independent B cell responses, perhaps due to their complex arrays of repetitive antigenic epitopes on virions, coupled with the induction of innate cytokines. Nevertheless, T cell help is usually necessary for generating long-term antibody responses in the form of long-lived plasma cells and memory B cells. In contrast, our lab has found that T cell-deficient mice infected with PyV develop long-lasting, protective antiviral IgG responses. I questioned whether these mice could generate TI B cell memory cells or long-lived plasma cells. I show that long-lasting anti-PyV antibody in T cell-deficient mice was not due to the presence of long-lived plasma cells or memory B cell responses. TCRβδ deficient mice, which lack both CD4 and CD8 T cells, had ~10 a times higher virus load persisting in various organs. Therefore, I hypothesized that the high level of persistent PyV antigen, in completely T cell-deficient mice, may activate naïve B cell populations continuously, thereby maintaining the long-lasting IgG responses. Prior to PyV infection, T cell-deficient mice received wild type CD8 T cells, which reduced PyV loads, and this was associated with decreased levels of antiviral serum IgG over time. As in TCRβδ deficient mice, high PyV loads were detected in the bone marrow, which is the site for B cell lymphopoiesis, I questioned how B cells develop in the presence of PyV antigen and still stay responsive to PyV, generating long-term antiviral IgG responses in the periphery. Studies have shown that self-antigens that trigger both B cell receptor signaling and TLR-MyD88 signaling pathways in the bone marrow lead to the breaking of B cell tolerance and production of autoantibody in the periphery. Thus, we hypothesized that high PyV levels in the bone marrow signal through both B cell-receptors and TLRs, allowing continuous antiviral antibody production by B cells. Using mice that are deficient in T cells and MyD88 signaling, I found that PyV-specific TI IgG levels gradually decreased, supporting this hypothesis. Thus, high PyV loads and innate signaling together can break B cell tolerance. During a persistent virus infection this can result in sustaining long-term protective T cell-independent IgG responses

Rotating dust solutions of Einstein's equations with 3-dimensional symmetry groups; Part 1: Two Killing fields spanned on u^{\alpha} and w^{\alpha }

For a rotating dust with a 3-dimensional symmetry group all possible metric forms can be classified and, within each class, explicitly written out. This is made possible by the formalism of Pleba\'nski based on the Darboux theorem. In the resulting coordinates, the Killing vector fields (if any exist) assume a special form. Each Killing vector field may be either spanned on the fields of velocity and rotation or linearly independent of them. By considering all such cases one arrives at the classification. With respect to the structures of the groups, this is just the Bianchi classification, but with all possible orientations of the orbits taken into account. In this paper, which is part 1 of a 3-part series, all solutions are considered for which two Killing fields are spanned on velocity and rotation. The solutions of Lanczos and G\"{o}del are identified as special cases, and their new invariant definitions are provided. In addition, a new invariant definition is given of the Ozsvath class III solution.Comment: 23 pages, LaTe

Profile of substance abusers attending at de-addiction center of GMERS medical college, Dharpur-Patan, Gujarat, India: a cross sectional study

Background: Although the history of substance abuse is as old as mankind itself, recently it has become a global problem that is influenced by social, economic, political, and psychosocial factors. The objective of the study was to study the socio-demographic profile of patients attending at de-addiction center.Methods: The present cross sectional study was conducted at de-addiction center of GMERS Medical College, Dharpur-Patan, North Gujarat, India during December 2014 to July 2015. After obtaining approval from Institutional ethical committee and taking written and verbal consent of patients, total 206 patients were interviewed using predesigned, pretested and semi structured proforma. Data thus collected were analysed using SPSS 17 (trial version).Results: Out of total 206 substance abusers, 138 (67%) patients were between the age group of 25 to 45 years.69% of the total abusers belonged to socio economic class 4 and 5. 14.6% substance abusers were illiterate 66.9% of the substance abusers were skilled and semi-skilled workers. Out of total 206 substance abusers, 102 (49.5%) patients had family history of substance abuse. 40.8% of the substance abusers had initiated substance abuse in adolescent age group while 45.6% of the substance abusers had initiated substance abuse between 20 to 30 years age group. Mean age of substance initiation in our study was 22±6 years. The mean duration of substance use was 18.1 years. Friends of substance abusers (peer pressure) were responsible for starting of substance abuse in majority of the substance abusers (81.6%). Out of total 206 substance abusers, 128 (62.1%) patients were addicted to alcohol.Conclusions: This study shows that youth is falling in vicious trap of drug abuse at early age. Awareness programs and camps need to be conducted at community level to address this major public health problem of substance use.

Broadband 200-nm second-harmonic generation in silicon in the telecom band.

Silicon is well known for its strong third-order optical nonlinearity, exhibiting efficient supercontinuum and four-wave mixing processes. A strong second-order effect that is naturally inhibited in silicon can also be observed, for example, by electrically breaking the inversion symmetry and quasi-phase matching the pump and the signal. To generate an efficient broadband second-harmonic signal, however, the most promising technique requires matching the group velocities of the pump and the signal. In this work, we utilize dispersion engineering of a silicon waveguide to achieve group velocity matching between the pump and the signal, along with an additional degree of freedom to broaden the second harmonic through the strong third-order nonlinearity. We demonstrate that the strong self-phase modulation and cross-phase modulation in silicon help broaden the second harmonic by 200 nm in the O-band. Furthermore, we show a waveguide design that can be used to generate a second-harmonic signal in the entire near-infrared region. Our work paves the way for various applications, such as efficient and broadband complementary-metal oxide semiconductor based on-chip frequency synthesizers, entangled photon pair generators, and optical parametric oscillators

A Non - Singular Cosmological Model with Shear and Rotation

We have investigated a non-static and rotating model of the universe with an imperfect fluid distribution. It is found that the model is free from singularity and represents an ever expanding universe with shear and rotation vanishing for large value of time.Comment: 10 pages, late

Uterine rupture: a preventable obstetric catastrophe

Background: Maternal health has long been acknowledged to be the cornerstone in public health. The objective of this study was to determine the incidence, etiology, risk factors, complications, treatment strategies, maternal and fetal outcome associated with uterine rupture and to determine how to decrease the maternal morbidity and mortality pertaining to it, as it is indeed a preventable obstetric catastrophe!Methods: This is a retrospective study which was carried out in our institute. Analysis of 45 cases of uterine rupture including scar dehiscence, registered/emergency, rupture occurring in the antepartum or intrapartum period, irrespective of previous vaginal or cesarean delivery was done between July 2017 to June 2019 out of 16,330 deliveries. None of the cases were excluded. Statistical analysis was done comparing the mortality in general population and study population and it was determined that it contributes to the maternal mortality significantly hence making it essential to promptly diagnose and treat the cases.Results: The incidence of rupture of uterus is average 0.27% (1 in 362). Out of 45 cases 9 (20%) were registered, and 36 (80%) were referred patients. The 20-30 years age group is the most vulnerable. Scarred uterus undergoing rupture were 34 (75.55%) as compared to rupture in intact uterus which were 11 (24.44%). The commonest modality of treatment used is suturing of tear which was done in 34 (75.55%) followed by total hysterectomy. There were 2 maternal deaths giving maternal mortality rate of 4.44% and perinatal mortality occurred in 18 (40%) cases.Conclusions: Uterine rupture is a dire emergency with a high incidence of maternal and fetal morbidity and mortality. Skilled attendance with accessible obstetric care, focused antenatal care, strict intrapartum monitoring and good surgical approach are key elements for the prevention and management of uterine rupture

Effect of Drying Conditions and Embedding Materials on Post-Harvest Quantitative Parameters in China Aster (Callistephus chinensis) Flowers

The study was undertaken to optimize conditions for dry flower production in China aster flowers. The experiment was conducted with eight treatment combinations consisting of two drying conditions viz., room drying (C1) and sun drying (C2) and four media viz. Sand (M1), Sand:Borax (1:1) (M2), Borax (M3) and Silicagel (M4) with factorial concept in completely randomized design. Per cent weight loss and moisture loss were signiflcantly higher under sun drying and silicagel during the entire process of drying from first day to fourth day. Moisture content was higher under room drying and borax from first day to fourth day

Knowledge of Cancer cervix and its causative agents among HIV-infected and HIV-uninfected adolescent women in rural Medical College in Maharashtra, India

Background: The aim of this study is to examine the knowledge of human papilloma virus (HPV) and cervical cancer among HIV-infected and HIV-uninfected female adolescents attending Antenatal OPD in Department of Obstetrics and Gynecology, Government Medical College, Miraj, Maharashtra, India.Methods: Subjects were recruited randomly from OPD attending patients.  A total of 30 subjects, 15 HIV-infected and 15 HIV-uninfected were selected via randomization and completed a measure of HPV knowledge, based on a previously validated instrument. The study took place in December 2017.Results: The overall mean score on the measure for all subjects was 43.3% (S.D. 10.9). There was no significant difference in HPV knowledge between the HIV-infected and HIV-uninfected groups. Based on results from a previous large-scale study using the same validated measure, this sample scored significantly worse on general HPV knowledge than samples from the other studies.Conclusions: Given the limited knowledge of HPV in this sample, there is greater need for education about the prevention of cervical cancer, specifically among high-risk adolescent women