Host immune responses in aged rhesus macaques against BBV152, an inactivated SARS-CoV-2 vaccine, and cross-neutralization with beta and delta variants.

The magnitude and duration of immune response to COVID-19 vaccination in older adults are known to be adversely affected due to immunosenescence and inflammaging. The threat of emerging variants warrants studies on immune response in older adults to primary vaccination and booster doses so as to understand the effectiveness of vaccines in countering the threat of emerging variants. Non-human primates (NHPs) are ideal translational models, as the immunological responses in NHPs are similar to those in humans, so it enables us to understand host immune responses to the vaccine. We initially studied humoral immune responses in aged rhesus macaques employing a three-dose regimen of BBV152, an inactivated SARS-CoV-2 vaccine. Initially, the study investigated whether the third dose enhances the neutralizing antibody (Nab) titer against the homologous virus strain (B.1) and variants of concern (Beta and Delta variants) in aged rhesus macaques immunized with BBV152, adjuvanted with Algel/Algel-IMDG (imidazoquinoline). Later, we also attempted to understand cellular immunity in terms of lymphoproliferation against γ-inactivated SARS-CoV-2 B.1 and delta in naïve and vaccinated rhesus macaques after a year of the third dose. Following the three-dose regimen with 6 µg of BBV152 with Algel-IMDG, animals had increased Nab responses across all SARS-CoV-2 variants studied, which suggested the importance of booster dose for the enhanced immune response against SARS-CoV-2-circulating variants. The study also revealed the pronounced cellular immunity against B.1 and delta variants of SARS-CoV-2 in the aged rhesus macaques even after a year of vaccination.

Needle-free injection system delivery of ZyCoV-D DNA vaccine demonstrated improved immunogenicity and protective efficacy in rhesus macaques against SARS-CoV-2.

The apprehension of needles related to injection site pain, risk of transmitting bloodborne pathogens, and effective mass immunization have led to the development of a needle-free injection system (NFIS). Here, we evaluated the efficacy of the NFIS and needle injection system (NIS) for the delivery and immunogenicity of DNA vaccine candidate ZyCoV-D in rhesus macaques against SARS-CoV-2 infection. Briefly, 20 rhesus macaques were divided into 5 groups (4 animals each), that is, I (1 mg dose by NIS), II (2 mg dose by NIS), III (1 mg dose by NFIS), IV (2 mg dose by NFIS) and V (phosphate-buffer saline [PBS]). The macaques were immunized with the vaccine candidates/PBS intradermally on Days 0, 28, and 56. Subsequently, the animals were challenged with live SARS-CoV-2 after 15 weeks of the first immunization. Blood, nasal swab, throat swab, and bronchoalveolar lavage fluid specimens were collected on 0, 1, 3, 5, and 7 days post infection from each animal to determine immune response and viral clearance. Among all the five groups, 2 mg dose by NFIS elicited significant titers of IgG and neutralizing antibody after immunization with enhancement in their titers postvirus challenge. Besides this, it also induced increased lymphocyte proliferation and cytokine response. The minimal viral load post-SARS-CoV-2 challenge and significant immune response in the immunized animals demonstrated the efficiency of NFIS in delivering 2 mg ZyCoV-D vaccine candidate.

Serosurvey for Nipah virus in bat population of southern part of India.

Nipah virus (NiV) is one of the priority pathogens with pandemic potential. Though the spread is far slower than SARS-CoV-2, case fatality is the biggest concern. Fruit bats belonging to genus Pteropus are identified to be the main reservoir of the virus causing sporadic cases and outbreaks in Malaysia, Bangladesh and India. The sudden emergence of Nipah in Kerala, India during 2018-2019 has been astonishing with respect to its introduction in the unaffected areas. With this, active Nipah virus surveillance was conducted among bat populations in Southern part of India viz., Karnataka, Kerala, Tamil Nadu, Telangana, Puducherry and Odisha during January-November 2019. Throat swabs/rectal swabs (n = 573) collected from Pteropus medius and Rousettus leschenaultii bat species and sera of Pteropus medius bats (n = 255) were screened to detect the presence of Nipah viral RNA and anti-Nipah IgG antibodies respectively. Of 255 P. medius bats sera samples, 51 bats (20%) captured from Karnataka, Kerala, Tamil Nadu and Puducherry demonstrated presence of anti-Nipah IgG antibodies. However, the presence of virus couldn't be detected in any of the bat specimens. The recent emergence of Nipah virus in Kerala in September 2021 warrants further surveillance of Nipah virus among bat populations from the affected and remaining states of India.

Immunogenicity and protective efficacy of inactivated SARS-CoV-2 vaccine candidate, BBV152 in rhesus macaques.

The COVID-19 pandemic is a global health crisis that poses a great challenge to the public health system of affected countries. Safe and effective vaccines are needed to overcome this crisis. Here, we develop and assess the protective efficacy and immunogenicity of an inactivated SARS-CoV-2 vaccine in rhesus macaques. Twenty macaques were divided into four groups of five animals each. One group was administered a placebo, while three groups were immunized with three different vaccine candidates of BBV152 at 0 and 14 days. All the macaques were challenged with SARS-CoV-2 fourteen days after the second dose. The protective response was observed with increasing SARS-CoV-2 specific IgG and neutralizing antibody titers from 3rd-week post-immunization. Viral clearance was observed from bronchoalveolar lavage fluid, nasal swab, throat swab and lung tissues at 7 days post-infection in the vaccinated groups. No evidence of pneumonia was observed by histopathological examination in vaccinated groups, unlike the placebo group which exhibited interstitial pneumonia and localization of viral antigen in the alveolar epithelium and macrophages by immunohistochemistry. This vaccine candidate BBV152 has completed Phase I/II (NCT04471519) clinical trials in India and is presently in phase III, data of this study substantiates the immunogenicity and protective efficacy of the vaccine candidates.

Detection of Nipah virus in Pteropus medius in 2019 outbreak from Ernakulam district, Kerala, India.

BACKGROUND: In June 2019, Nipah virus (NiV) infection was detected in a 21-year-old male (index case) of Ernakulum, Kerala, India. This study was undertaken to determine if NiV was in circulation in Pteropus species (spp) in those areas where the index case had visit history in 1 month. METHODS: Specialized techniques were used to trap the Pteropus medius bats (random sampling) in the vicinity of the index case area. Throat and rectal swabs samples of 141 bats along with visceral organs of 92 bats were collected to detect the presence of NiV by real-time reverse transcriptase-polymerase chain reaction (qRTPCR). Serum samples of 52 bats were tested for anti-NiV Immunoglobulin (Ig) G antibodies by Enzyme-Linked Immunosorbent Assay (ELISA). The complete genome of NiV was sequenced by next-generation sequencing (NGS) from the tissues and swab samples of bats. RESULTS: One rectal swab sample and three bats visceral organs were found positive for the NiV. Interestingly, 20.68% (12/58) of Pteropus were positive for anti-NiV IgG antibodies. NiV sequences of 18,172; 17,200 and 15,100 nucleotide bps could be retrieved from three Pteropus bats. CONCLUSION: A distinct cluster of NiV sequences, with significant net-evolutionary nucleotide divergence, was obtained, suggesting the circulation of new genotype (I-India) in South India. NiV Positivity in Pteropus spp. of bats revealed that NiV is circulating in many districts of Kerala state, and active surveillance of NiV should be immediately set up to know the hotspot area for NiV infection.

Study of Kyasanur forest disease viremia, antibody kinetics, and virus infection in target organs of Macaca radiata.

The present manuscript deals with experimental infections of bonnet macaques (Macaca radiata) to study disease progression for better insights into the Kyasanur Forest Disease (KFD) pathogenesis and transmission. Experimentally, 10 monkeys were inoculated with KFD virus (KFDV) (high or low dose) and were regularly monitored and sampled for various body fluids and tissues at preset time points. We found that only 2 out of the 10 animals showed marked clinical signs becoming moribund, both in the low dose group, even though viremia, virus shedding in the secretions and excretions were evident in all inoculated monkeys. Anti-KFDV immunoglobulin (Ig)M antibody response was observed around a week after inoculation and anti-KFDV IgG antibody response after two weeks. Anaemia, leucopenia, thrombocytopenia, monocytosis, increase in average clotting time, and reduction in the serum protein levels were evident. The virus could be re-isolated from the skin during the viremic period. The persistence of viral RNA in the gastrointestinal tract and lymph nodes was seen up to 53 and 81 days respectively. Neuro-invasion was observed only in moribund macaques. Re-challenge with the virus after 21 days of initial inoculation in a monkey did not result in virus shedding or immune response boosting.

Recent Advancement in Bio-precursor derived graphene quantum dots: Synthesis, Characterization and Toxicological Perspective.

Graphene quantum dots (GQDs), impressive materials with enormous future potential, are reviewed from their inception, including different precursors. Considering the increasing burden of industrial and ecological bio-waste, there is an urgency to develop techniques which will convert biowaste into active moieties of interest. Amongst the various materials explored, we selectively highlight the use of potential carbon containing bioprecursors (e.g. plant-based, amino acids, carbohydrates), and industrial waste and its conversion into GQDs with negligible use of chemicals. This review focuses on the effects of different processing parameters that affect the properties of GQDs, including the surface functionalization, paradigmatic characterization, toxicity and biocompatibility issues of bioprecursor derived GQDs. This review also examines current challenges and s the ongoing exploration of potential bioprecursors for ecofriendly GQD synthesis for future applications. This review sheds further light on the electronic and optical properties of GQDs along with the effects of doping on the same. This review may aid in future design approaches and applications of GQDs in the biomedical and materials design fields.

Graphene-based nanocomposites for sensitivity enhancement of surface plasmon resonance sensor for biological and chemical sensing: A review.

Surface plasmon resonance (SPR) offers exceptional advantages such as label-free, in-situ and real-time measurement ability that facilitates the study of molecular or chemical binding events. Besides, SPR lacks in the detection of various binding events, particularly involving low molecular weight molecules. This drawback ultimately resulted in the development of several sensitivity enhancement methodologies and their application in the various area. Among graphene materials, graphene-based nanocomposites stands out owing to its significant properties such as strong adsorption of molecules, signal amplification by optical, high carrier mobility, electronic bridging, ease of fabrication and therefore, have established as an important sensitivity enhancement substrate for SPR. Also, graphene-based nanocomposites could amplify the signal generated by plasmon material and increase the sensitivity of molecular detection up to femto to atto molar level. This review focuses on the current important developments made in the potential research avenue of SPR and fiber optics based SPR for chemical and biological sensing. Latest trends and challenges in engineering and applications of graphene-based nanocomposites enhanced sensors for detecting minute and low concentration biological and chemical analytes are reviewed comprehensively. This review may aid in futuristic designing approaches and application of grapheneous sensor platforms for sensitive plasmonic nano-sensors.

Animal models for some important RNA viruses of public health concern in SEARO countries: viral hemorrhagic fever.

Viral hemorrhagic fevers (VHFs) are major public health problems in the South-East Asia Regional (SEAR) countries. VHFs are a group of illnesses; that are caused by four families of viruses, viz. Arenaviridae, Bunyaviridae, Filoviridae and Flaviviridae. All VHFs have common features: they affect several organs and damage the blood vessels. These symptoms are often accompanied by hemorrhage. To understand pathogenesis, genetic and environmental influence that increase the risk of VHFs, efficacy and safety studies on candidate vaccines and testing of various therapeutic agents, appropriate animal models are essential tools in public and animals health. In the current review, the suitable animal models for Flavivirus [Dengue hemorhagic fever (DHF), Kyasanur forest disease (KFD)]; Bunyavirus [Crimean-Congo hemorrhagic fever (CCHF), Hantavirus fever (HF)]; and Paramyxovirus [Nipah virus fever (NiV)] have been reviewed with specific emphasis on emerging and reemerging viruses in SEAR countries.

Expression profile of immune response genes during acute myopathy induced by chikungunya virus in a mouse model.

During the recent re-emergence of chikungunya, clinical complications and deaths were recorded. Persistent musculoskeletal pain, arthralgia, arthritis were among the most common complications. To understand pathogenesis of CHIKV induced disease, we developed suckling, outbred mouse model presenting with severe myopathology. Histopathology, dynamics of viral load, IgG antibodies/isotypes, serum cytokines by cytometric bead array and mRNA expression levels of immune response genes in the target tissue by Taqman Low Density Array were studied. Peak viral load was associated with peak serum levels of CCL-2,KC, CCL-4, RANTES, IL-6, IL-10, CSF-3, and locally very high mRNA expression of CCL-2, CXCL-10, CXCL-11 and concomitant IFNγ, IL-10, STAT-1, SOCS-1 and CSF-3 suggesting strong IFNγ program. Symptomatic phase correlated with peak serum levels of IL-2, IFNγ, IL-17, CCL-3, IL-1ß, eotaxin, IL-9 and CSF-2 and locally with peak mRNA expression of macrophage induced pro inflammatory cytokines and immune infiltration biased towards Th1. IgG antibodies were detected on day 6PI, reaching high titres by day 11PI. IgG2a was the predominant isotype, indicating Th1 bias. This is the first report of comprehensive analysis of immune response genes expression in target tissue of CHIKV mouse model. The data would contribute significantly in understanding pathogenesis of CHIKV disease and viral myopathies.

Genomic characterization of Nipah virus, West Bengal, India.

An intrafamilial outbreak in West Bengal, India, involving 5 deaths and person-to-person transmission was attributed to Nipah virus. Full-genome sequence of Nipah virus (18,252 nt) amplified from lung tissue showed 99.2% nt and 99.8% aa identity with the Bangladesh-2004 isolate, suggesting a common source of the virus.