Flt3 agonist enhances immunogenicity of arenavirus vector-based simian immunodeficiency virus vaccine in macaques.

Arenaviral vaccine vectors encoding simian immunodeficiency virus (SIV) immunogens are capable of inducing efficacious humoral and cellular immune responses in nonhuman primates. Several studies have evaluated the use of immune modulators to further enhance vaccine-induced T-cell responses. The hematopoietic growth factor Flt3L drives the expansion of various bone marrow progenitor populations, and administration of Flt3L was shown to promote expansion of dendritic cell populations in spleen and blood, which are targets of arenaviral vectors. Therefore, we evaluated the potential of Flt3 signaling to enhance the immunogenicity of arenaviral vaccines encoding SIV immunogens (SIVSME543 Gag, Env, and Pol) in rhesus macaques, with a rhesus-specific engineered Flt3L-Fc fusion protein. In healthy animals, administration of Flt3L-Fc led to a 10- to 100-fold increase in type 1 dendritic cells 7 days after dosing, with no antidrug antibody (ADA) generation after repeated dosing. We observed that administration of Flt3L-Fc fusion protein 7 days before arenaviral vaccine increased the frequency and activation of innate immune cells and enhanced T-cell activation with no treatment-related adverse events. Flt3L-Fc administration induced early innate immune activation, leading to a significant enhancement in magnitude, breadth, and polyfunctionality of vaccine-induced T-cell responses. The Flt3L-Fc enhancement in vaccine immunogenicity was comparable to a combination with αCTLA-4 and supports the use of safe and effective variants of Flt3L to augment therapeutic vaccine-induced T-cell responses.IMPORTANCEInduction of a robust human immunodeficiency virus (HIV)-specific CD4+ and CD8+ T-cell response through therapeutic vaccination is considered essential for HIV cure. Arenaviral vaccine vectors encoding simian immunodeficiency virus (SIV) immunogens have demonstrated strong immunogenicity and efficacy in nonhuman primates. Here, we demonstrate that the immunogenicity of arenaviral vectors encoding SIV immunogens can be enhanced by administration of Flt3L-Fc fusion protein 7 days before vaccination. Flt3L-Fc-mediated increase in dendritic cells led to robust improvements in vaccine-induced T- and B-cell responses compared with vaccine alone, and Flt3L-Fc dosing was not associated with any treatment-related adverse events. Importantly, immune modulation by either Flt3L-Fc or αCTLA-4 led to comparable enhancement in vaccine response. These results indicate that the addition of Flt3L-Fc fusion protein before vaccine administration can significantly enhance vaccine immunogenicity. Thus, safe and effective Flt3L variants could be utilized as part of a combination therapy for HIV cure.

A Peptide-Based Oscillator.

Living organisms are replete with rhythmic and oscillatory behavior at all levels, to the extent that oscillations have been termed as a defining attribute of life. Recent studies of synthetic oscillators that mimic such functions have shown decayed cycles in batch-mode reactions or sustained oscillatory kinetics under flow conditions. Considering the hypothesized functionality of peptides in early chemical evolution and their central role in current bio-nanotechnology, we now reveal a peptide-based oscillator. Oscillatory behavior was achieved by coupling coiled-coil-based replication processes as positive feedback to controlled initiation and inhibition pathways in a continuously stirred tank reactor (CSTR). Our results stress that assembly into the supramolecular structure and specific interactions with the replication substrates are crucial for oscillations. The replication-inhibition processes were first studied in batch mode, which produced a single damped cycle. Thereafter, combined experimental and theoretical characterization of the replication process in a CSTR under different flow and environmental (pH, redox) conditions demonstrated reasonably sustained oscillations. We propose that studies in this direction might pave the way to the design of robust oscillation networks that mimic the autonomous behavior of proteins in cells (e.g., in the cyanobacterial circadian clock) and hence hint at feasible pathways that accelerated the transition from simple peptides to extant enzymes.

A Prospective Observational Study of Autoimmune Encephalitis in Northwestern India.

OBJECTIVES: Autoimmune encephalitis (AIE) is a group of rare, increasingly recognized, potentially reversible, noninfectious causes of unexplained encephalitis. It affects any age-group and has a plethora of clinical presentations, the most common being the neuropsychiatric manifestation. The diagnosis of this entity at the right time and proper treatment with immunotherapy can save many lives. In this study, we describe the demographic profile, clinical spectrum, diagnosis, and treatment of 42 patients with features of AIE. MATERIALS AND METHODS: This is a prospective study where 42 cases were selected from a tertiary care center in Northwestern India. Patients with suspected AIE underwent detailed clinical assessment, routine blood tests, magnetic resonance imaging (MRI) brain, electroencephalography (EEG), cerebrospinal fluid (CSF) study, and autoimmune profile in blood and CSF. Screening for malignancy was done in all patients with computer tomography (CT) thorax and abdomen and tumor markers. RESULTS: Among 42 patients, males, and females were almost equally affected. The mean age of onset was 31 years. Anti-N-methyl-D-aspartate receptor (anti-NMDAR) Encephalitis was the commonest of all AIE (57%) followed by anti-leucine-rich glioma inactivated-1 (anti-LGI-1) related AIE (11.9%), anti-contactin-associated protein 2 (anti-CASPR2) related AIE (4.7%), and steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) related to antithyroid peroxidase (anti-TPO) antibody (2.3%). Neuropsychiatric manifestation is the commonest. The seizure was noted in around 72% of patients, the commonest in the anti-NMDAR group. Faciobrachial dystonic seizure (FBDS) was noted in all five anti-LG1-1 encephalitis patients. CSF abnormalities were seen in 33.3% of patients in the form of pleocytosis or raised protein, or both. MRI abnormality was seen in 52% of patients. EEG was abnormal in 10% of patients, and delta brush was noted in three anti-NMDAR patients. All patients received immunotherapy in the form of intravenous immunoglobulin (IVIg) or pulse IV methylprednisolone (IVMPS), or both. Two patients nonresponsive to IVIg and IVMPS received rituximab. Almost all patients responded to immunotherapy. CONCLUSION: Autoimmune encephalitis (AIE), a potentially treatable immune-responsive entity, is a common neurological problem and may be an answer to a large number of cases having unexplained encephalitis. Good clinical acumen and knowledge are required for early diagnosis and treatment of this potentially reversible disorder. How to cite this article: Sharma B, Paul M, Bagaria AK. A Prospective Observational Study of Autoimmune Encephalitis in Northwestern India. J Assoc Physicians India 2023;71(9):39-44.

A review on neuropharmacological role of erucic acid: an omega-9 fatty acid from edible oils.

Neurodegenerative diseases (ND) are characterised by loss of neurons in the brain and spinal cord. For the normal functioning of the brain, divers group of fatty acids in the form of glycerophospholipids, glycerol ether lipids, cerebrosides, sulfatides, and gangliosides are essential. They are present abundantly in the nervous system and are actively involved in both the development and maintenance of the nervous system. A dietary deficiency of essential fatty acid during development results in hypomyelination state which affects various neuronal functions. Several studies suggested that age remains the primary risk factor for almost all neurodegenerative disorders. The potential contribution of these fatty acids in the progression of neurodegenerative disorders is indispensable. Erucic acid an omega 9 fatty acid, which is obtained from edible oils has proven to cause myocardial lipidosis, heart lesions and hepatic steatosis in animals therefore, its content in edible oils is restricted to certain levels by regulatory agencies. However, erucic acid in the form of a mixture with oleic acid is often used as a dietary treatment for the management of adrenoleukodystrophy without any cardiotoxicity. Our literature search revealed that, erucic acid reported to enhance cognitive function, interact with peroxisome proliferator activated receptors (PPARs), inhibit elastase and thrombin. In this review first we have attempted to describe the relationship between fatty acids and neurodegeneration followed by a description on the pharmacology of erucic acid. The overall purpose of this review is to analyse toxic and beneficial neuropharmacological effects of erucic acid.

Neuroborreliosis in India - A Diagnostic Challenge and a Great Mimicker: A Case Series.

OBJECTIVES: Neuroborreliosis is generally known to be a disease confined to the Western part of the globe. It is not commonly encountered in this part of the world. Interestingly, we recently came across a series of cases of Lyme's disease with a plethora of neurological presentations. Most of the cases were a diagnostic dilemma, with poor response to immunotherapy and on subsequent evaluation all were found to have positive Borrelia antibodies. MATERIALS AND METHODS: Eight cases were selected from the tertiary care hospital in North western India. Patients were suspected to have Neuroborreliosis whose neurological presentations were atypical for other classical neurological disorders, who had a progressive or relapsing clinical course and had responded poorly to the initial treatment given for the previous neurological diagnosis. Skin lesions were present in some cases. The patients underwent a detailed clinical assessment which comprised of an elaborate history including history of travel, any insect bite or skin rashes along with a complete systemic and neurological examination. All the required blood investigations, Magnetic Resonance Imaging (MRI) Brain, Computer Tomography Angiography (CT), Nerve conduction study (NCS) and Electromyographic (EMG) studies and Cerebrospinal fluid (CSF) studies were done as indicated in each case. Borrelia antibody titre was done in all the patients using immunoblot technique. RESULTS: Among the 8 patients, 6 were male and 2 were females. The age group was between 25-70 years. The clinical presentation was acute, subacute or chronic. One patient gave a clear history of tick bite. Two patients had skin lesions and one had the pathognomic "eschar". All the suspected 8 patients had either IgG or IgM or both IgG and IgM Borrelia antibodies positive. Almost all the patients had previously received either steroids or intravenous immunoglobulins, but had not adequately responded to immunotherapy. These patients were given a trial of injectable Ceftriaxone and oral Doxycycline. Most of them either showed partial or complete clinical improvement. CONCLUSION: Lyme's disease, a common disease of the west does exist in the Indian subcontinent as well. Because of increasing global travel and migration and change in vector habitat the disease seems to have percolated in the non endemic areas too. Proper history of travel or exposure to tick bite is important. We want to emphasize, Neuroborreliosis, a great mimicker may have diverse and varied neurological presentations and has a potential for reversibility with appropriate treatment even after a significant delay in diagnosis.

IL-17-CXC Chemokine Receptor 2 Axis Facilitates Breast Cancer Progression by Up-Regulating Neutrophil Recruitment.

Recent evidence suggests that interactions among proinflammatory cytokines, chemokines, and cancer cell-recruited neutrophils result in enhanced metastasis and chemotherapy resistance. Nonetheless, the detailed mechanism remains unclear. Our aim was to discover the role of IL-17, CXC chemokine receptor 2 (CXCR2) ligands, and cancer-associated neutrophils in chemotherapy resistance and metastasis in breast cancer. Mice were injected with Cl66 murine mammary tumor cells, Cl66 cells resistant to doxorubicin (Cl66-Dox), or Cl66 cells resistant to paclitaxel (Cl66-Pac). Higher levels of IL-17 receptor, CXCR2 chemokines, and CXCR2 were observed in tumors generated from Cl66-Dox and Cl66-Pac cells in comparison with tumors generated from Cl66 cells. Tumors generated from Cl66-Dox and Cl66-Pac cells had higher infiltration of neutrophils and T helper 17 cells. In comparison with primary tumor sites, there were increased levels of CXCR2, CXCR2 ligands, and IL-17 receptor within the metastatic lesions. Moreover, IL-17 increased the expression of CXCR2 ligands and cell proliferation of Cl66 cells. The supernatant of Cl66-Dox and Cl66-Pac cells enhanced neutrophil chemotaxis. In addition, IL-17-induced neutrophil chemotaxis was dependent on CXCR2 signaling. Collectively, these data demonstrate that the IL-17-CXCR2 axis facilitates the recruitment of neutrophils to the tumor sites, thus allowing them to play a cancer-promoting role in cancer progression.

Detection of co-infection of Gardnerella vaginalis and Atopobium vaginae using qualitative PCR: A better predictor of bacterial vaginosis.

The present study aimed to determine the utility of detection of co-infection of Gardnerella vaginalis and Atopobium vaginae using qualitative PCR for diagnosing bacterial vaginosis (BV). Vaginal samples (n = 385) categorized as positive (n = 108) or negative (n = 208) for bacterial vaginosis based on the Nugent scoring system, were analyzed for the presence of G. vaginalis and A. vaginae by conventional PCR. We compared the sensitivity, specificity, positive predictive value, negative predictive value and odds ratio for the detection of each bacterium alone with the combination of the two bacteria for diagnosing BV. The detection of co-infection of the two bacteria demonstrated a sensitivity of 96%, a specificity of 82.9%, a positive predictive value of 68.5%, a negative predictive value of 98.2% with an odds ratio of 116 (CI -32 - 409). In our study, we found a high sensitivity, specificity, negative predictive value and odds ratio for the detection of co-infection of A. vaginae and G. vaginalis for the diagnosis of BV.

Isolated Acute Cerebrovascular Involvement in COVID-19 without Fever and Respiratory Symptoms: An Indian Perspective.

BACKGROUND: Stroke in COVID-19 has been reported in critically ill patients globally. Stroke as a singular manifestation of COVID-19 in absence of typical symptoms (fever, cough and dyspnea) is under- recognized. OBJECTIVE: Comparative study of clinical and laboratory parameters of COVID-19 stroke patients without typical symptoms at onset with stroke cases without COVID-19 infection. METHODS: 28consecutive stroke patients, eight with coronavirus infection and twenty without COVID-19 admitted to neurology department of a tertiary care centre of North West India between 20 June,2020 and 19 July,2020 were enrolled in this retrospective study. RESULTS: COVID-19 patients had higher frequency of seizures (4[50%]) vs 2[10%];p= 0.03)and altered mental status(6[75%] vs 6[30%] p= 0.04). Severity of ischemic stroke(NIHSS >20, 3[75 %] vs 2[18%])and mortality(p=0.04)despite comparable vascular risk factors for stroke between the two groups was higher in COVID-19 patients. Three out of four COVID-19 young strokes died. Two females with COVID-19 did not develop any typical symptoms, six males(75%) developed fever with dyspnea after a mean delay of 2.7 days(Standard deviation 1.7) from stroke onset. All six patients who developed fever subsequently expired. Inflammatory markers (neutrophil to lymphocyte ratio;p<0.001and ESR: p<0.001), transaminases(p=0.038) and creatinine (p=0.009) were significantly elevated in COVID-19 patients. CONCLUSION: Isolated cerebrovascular involvement can be a presentation of COVID-19.Stroke severity and mortality is higher in COVID-19 with young strokes being no exemption. Development of fever was associated with clinical worsening. COVID-19 pandemic is far from over in India, such atypical presentations need to be recognized early and warrant stringent diagnostic protocols.

Bacterial coinfections and secondary infections in COVID-19 patients from a tertiary care hospital of northern India: Time to adhere to culture-based practices.

OBJECTIVE: Bacterial co-pathogens are common in various viral respiratory tract infections, leading to increased disease severity and mortality. Still, they are understudied during large outbreaks and pandemics. This study was conducted to highlight the overall burden of these infections in COVID-19 patients admitted to our tertiary care hospital, along with their antibiotic susceptibility patterns. MATERIAL AND METHODS: During the six-month study period, clinical samples (blood samples, respiratory samples, and sterile body fluids, including cerebrospinal fluid [CSF]) of COVID-19 patients with suspected bacterial coinfections (at presentation) or secondary infections (after 48 hours of hospitalization) were received and processed for the same. RESULTS: Clinical samples of 814 COVID-19 patients were received for bacterial culture and susceptibility. Out of the total patient sample, 75% had already received empirical antibiotics before the samples were sent for analysis. Overall, 17.9% of cultures were positive for bacterial infections. Out of the total patients with bacterial infection, 74% (108/146) of patients had secondary bacterial infections (after 48 hours of hospitalization) and 26% (38/146) had bacterial coinfections (at the time of admission). Out of the 143 total isolates obtained, the majority (86%) were gram-negative organisms, of which Acinetobacter species was the commonest organism (35.6%), followed by Klebsiella pneumoniae (18.1%). The majority (50.7%) of the pathogenic organisms reported were multidrug resistant. CONCLUSION: The overall rate of secondary bacterial infections (SBIs) in our study was lower (7.9%) than reported by other studies. A rational approach would be to adhere to the practice of initiating culture-based guidance for antibiotics and to restrict unnecessary empirical antimicrobial therapy.

Biogenic Silver Nanoparticles: Evaluation of Their Biological and Catalytic Potential.

The biogenic tailoring of silver nanoparticles using plant extract is becoming an attractive approach in the current scenario. Manilkara zapota (MZ) is well known for its antibacterial, hepato-protective, anti-inflammatory, anti-tussive, anti-fungal, anti-tumour, and free radical scavenging potential. Its plants extract is a rich source of secondary metabolites. Nowadays, silver nanoparticles (AgNPs) have been advocated for a variety of biomedical applications. In present work, silver nanoparticles have been synthesized using an aqueous extract of MZ, physicochemically characterized and finally evaluated for antimicrobial effects, catalytic reduction/degradation of organic dyes and cytotoxicity. The nanosized AgNPs (~ 84 nm) were found to possess prominent antibacterial potential against gram positive and gram negative pathogens (MIC 50 µg/ml) in comparison to native plant extract. Moreover, these particles were found to be non-toxic and efficient eradicators of environmental toxicants via rapid catalytic reduction of toxic chemicals and dyes. Altogether, these results suggest promising potential of these nanoparticles that can be used as multifunctional agents for future biomedical applications.