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[This corrects the article DOI: 10.3389/fimmu.2026.1846926.].

Chikungunya virus (CHIKV) infection causes acute febrile illness and severe joint inflammation, with some patients progressing to chronic arthritis. Early isotype-switched neutralizing antibody (nAb) responses have been associated with protection from chronic arthritis, but the cellular and molecular features of these early responses remain poorly defined. We performed single-cell sorting of plasmablasts (PBs) from patients with acute CHIKV infection and generated 94 human monoclonal antibodies (mAbs). These were evaluated for binding to CHIKV-infected Vero cells and to purified CHIKV, neutralizing activity, isotype distribution, somatic hypermutation (SHM), and immunoglobulin gene usage. PB-derived antibodies were compared with CHIKV-specific memory B cell (MBC)-derived antibodies from seropositive individuals. Over one-third of PB-derived mAbs recognized CHIKV-infected Vero cells, and most were class-switched. Among these, 12 bound to purified CHIKV, and 6 of them showed neutralizing activity. All PB-derived nAbs had germline-like sequences with little to no SHM, and four displayed shared clonotypic features, including a conserved `WEL' motif in the CDRH3 region. Conversely, CHIKV-specific MBC-derived nAbs showed diverse but often higher levels of SHM, consistent with affinity maturation. Together, our findings suggest that early nAb responses generated during acute CHIKV infection are germline-biased with overlapping features suggestive of convergent clonotype responses, providing a cellular and molecular basis of the early protective humoral immunity.

Dengue is a global epidemic causing over 100 million cases annually. The clinical symptoms range from mild fever to severe hemorrhage and shock, including some fatalities. The current paradigm is that these severe dengue cases occur mostly during secondary infections due to antibody-dependent enhancement after infection with a different dengue virus serotype. India has the highest dengue burden worldwide, but little is known about disease severity and its association with primary and secondary dengue infections. To address this issue, we examined 619 children with febrile dengue-confirmed infection from three hospitals in different regions of India. We classified primary and secondary infections based on IgM:IgG ratios using a dengue-specific enzyme-linked immunosorbent assay according to the World Health Organization guidelines. We found that primary dengue infections accounted for more than half of total clinical cases (344 of 619), severe dengue cases (112 of 202) and fatalities (5 of 7). Consistent with the classification based on binding antibody data, dengue neutralizing antibody titers were also significantly lower in primary infections compared to secondary infections ( P  ≤ 0.0001). Our findings question the currently widely held belief that severe dengue is associated predominantly with secondary infections and emphasizes the importance of developing vaccines or treatments to protect dengue-naive populations. In an analysis of severe dengue cases in a cohort of children in India, more than half could be attributed to primary rather than secondary infection, suggesting that primary dengue infections might also contribute substantially to severe disease burden.

Chikungunya virus (CHIKV) infection causes acute febrile illness in humans, and some of these individuals develop a debilitating chronic arthritis that can persist for months to years for reasons that remain poorly understood. In this study from India, we characterized antibody response patterns in febrile chikungunya patients and further assessed the association of these initial febrile-phase antibody response patterns with protection versus progression to developing chronic arthritis. We found 5 distinct patterns of the antibody responses in the febrile phase: no CHIKV binding or neutralizing (NT) antibodies but PCR positive, IgM alone with no NT activity, IgM alone with NT activity, IgM and IgG without NT activity, and IgM and IgG with NT activity. A 20-month follow-up showed that appearance of NT activity regardless of antibody isotype or appearance of IgG regardless of NT activity during the initial febrile phase was associated with a robust protection against developing chronic arthritis in the future. These findings, while providing potentially novel insights on correlates of protective immunity against chikungunya-induced chronic arthritis, suggest that qualitative differences in the antibody response patterns that have evolved during the febrile phase can serve as biomarkers that allow prediction of protection or progression to chronic arthritis in the future.

Previous studies showed that a discrete population of the CD8 T cells with HLADR+CD38+ phenotype expand massively during the acute febrile phase of dengue natural infection. Although about a third of these massively expanding HLADR+CD38+ CD8 T cells were of CD69high phenotype, only a small fraction of them produced IFNγ upon in vitro peptide stimulation. What other cytokines/ chemokines do these peptides stimulated HLADR+CD38+ CD8 T cells express, what transcriptional profiles distinguish the CD69+IFNγ+, CD69+IFNγ-, and CD69-IFNγ- subsets, and whether the expansion of the total HLADR+CD38+ CD8 T cells or the IFNγ producing CD8 T cells differ depending on disease severity remained unclear. This study addresses these knowledge gaps. We find that the CD69+IFNγ+ subset uniquely expressed key genes involved in protein translation, cellular metabolism, proliferation and dendritic cell cross talk. Both the CD69+IFNγ+ and CD69+IFNγ- subsets had an antigen responsive gene signature with genes involved in cytotoxic effector functions, regulation of T cell receptor signaling, signaling by MAPK, chemotaxis and T cell trafficking to inflamed tissues with the expression being more robust in the IFNγ+ CD69+ subset. On the other hand, the CD69- IFNγ- subset was biased towards expression of genes that both augment and dampen T cell responses. Lastly, the expansion of total HLADR+ CD38+ CD8 T cells and also the IFNγ producing HLADR+ CD38+ CD8 T cells was similar in patients with different grades of disease. Taken together, this study provides valuable insights into the inherent diversity of the effector CD8 T cell response during dengue.

Previous studies have shown that plasmablasts expand massively in dengue patients as compared to many other situations such as influenza infection or vaccination. However, a detailed understanding of the phenotypes and transcriptional features of these cells is lacking. Moreover, despite India having nearly a third of global dengue disease burden, there is virtually no information on plasmablasts responses in dengue patients from India. Here, we provide a detailed characterization of plasmablast responses from dengue confirmed febrile children in India. Immunophenotyping and RNA seq analysis showed that in addition to secreting dengue specific antibodies, these massively expanding cells expressed several adhesion molecules, chemokines and chemokine receptors that are involved in endothelial interactions, homing to skin or mucosal tissues including intestine. Surprisingly, we found that these cells also upregulated expression of several cytokine genes that are involved in angiogenesis, leukocyte extravasation and vascular permeability. These transcriptional features were qualitatively similar to plasmablasts from influenza vaccinees. Interestingly, the expansion of the plasmablasts in dengue patients was significantly lower in patients with primary dengue infection compared to those with secondary dengue. Moreover, within the primary dengue patients, their expansion was significantly lower in patients with mild dengue infection (DI) compared to patients with dengue with warning signs (DW) or severe dengue (SD). These results significantly improve our understanding of human plasmablast responses in dengue. Importance Dengue is a globally spreading with over 100 million clinical cases annually with symptoms ranging from mild self-limiting febrile illness to more severe and sometimes life-threatening dengue hemorrhagic fever or shock, especially among children. India contributes nearly a third of global dengue disease burden. The pathophysiology of dengue is complex and remains poorly understood despite many advances indicating a key role for antibody dependent enhancement of infection. While serum antibodies have been extensively studied, the characteristics of the cellular factories responsible for antibody production, i.e., plasmablasts, are only beginning to emerge. This study provides a comprehensive understanding of the magnitude, phenotype, functional and transcriptional profiles of human plasmablasts from dengue patients in India.

Background and aims Amaranth is an important underutilized crop with high nutritional value but due to acidic soils and low nutrient availability, its production is low in Uttarakhand hills. Use of inorganic chemicals is restricted as they may disturb the fragile Himalayan ecosystem. Therefore, native cold tolerant Bacillus spp. isolates were used to assess their effect on growth and yield enhancement in amaranth. Methods A repository of 120 isolates of Bacillus spp. was developed and evaluated for their cold tolerance ability and PGP (Plant Growth Promoting) traits. Among these isolates, three potential isolates (BS-27, BS-41, BS-58) were selected for the field experiments to assess their effects on plant growth, soil nutrients (N, P and K) availability, nutrient uptake and yield of amaranth. Effect of different treatments on the nutrient use efficiency of amaranth was also determined. Results Biopriming of amaranth seeds by the selected three isolates exhibited a significant enhancement in plant growth and yield under field conditions. Among the different treatments, T-8 (BS-27 + BS-58) exhibited a maximum increase in grain yield (36.94%) closely followed by T-4 (BS-27; 33.80%). A significant increase (36.18%, 32.45 and 17.11%) in soil nutrients (NPK) and their uptake (68.01%, 104.16 and 116.46%) was recorded in different treatments. Principal component analysis revealed a positive correlation between soil nutrients and their uptake by host plants. The rpoB gene sequencing and phylogenetic analysis suggested the identity of BS-27 and BS-41 as B. pumilus and BS-58 as B. subtilis. Conclusion Our study shows that plant growth promoting bacteria (PGPB) can enhance the nutrient use efficiency of the host plant that further contributes to increase the crop yield. A significant increase in crop yield suggests that regular use of such effective PGPBs by farmers may increase the soil fertility and crop yield. Ultimately, this will lead towards food security under the organic farming framework in general, and sustainable crop production in particular.

The hot deformation behavior of Al 2024 was studied by isothermal hot compression tests in the temperature range of 250–500 °C and strain rate range of 10 −3 to 10 2  s −1 in a computer-controlled 50 kN servo-hydraulic universal testing machine (UTM). The results show that the flow stress of Al 2024 alloy increases with strain rate and decreases after a peak value, indicating dynamic recovery and recrystallization. The processing map exhibits two domains of optimum efficiency for hot deformation at different strains, including the low strain rate domain at 500 °C and between 10 −2 and 10 −1  s −1 and the high strain rate domain in 250 and 300 °C in the strain rate range of 10 1 to 10 2  s −1 . An attempt has been made in this article to generate a new hybrid 4D process map which illustrates contours of power dissipation and instability in the 3D space of strain rate, temperature, and strain.

Aim: Our aim of this study was to evaluate the diagnostic accuracy of staging positron emission tomography/computed tomography (PET/CT) in early breast cancers (EBCs) and to assess its impact on disease management. Patients and Methods: We retrospectively reviewed preoperative PET/CT scans of patients from January 2015 to December 2018 with Stage I/II, clinically T1-T2 N0-N1 breast cancers. The diagnostic performance of PET/CT for nodal (N) and distant metastases (M), its correlation with patient/tumor-specific factors, and its impact on disease management were analyzed using histopathology/clinical follow-up as standards of reference. Results: Of 158 patients evaluated, 14% of patients were Stage I (T1N0), 60% were Stage IIA (T1N1, T2N0), and 26% were Stage IIB (T2N1). Sensitivity, specificity, and the diagnostic accuracy of PET/CT for axillary staging were 76%, 97%, and 84% and for distant metastasis evaluation were 100%, 98%, and 99%, respectively. The diagnostic accuracy of PET/CT for axillary staging was lower for low-grade, T1 tumors, postmenopausal group, and luminal A pathological subtype (77%, 84%, 81%, and 73%, respectively) compared to high-grade, T2 tumors, premenopausal group, and nonluminal A subtype (88%, 88%, 94%, and 87%, respectively). Distant metastases were detected on PET/CT in overall 16% (n = 25) of the patients (9% in Stage IIA and 27% in Stage IIB). PET/CT also incidentally identified clinically occult internal mammary nodes in 5% (n = 8) and organ-confined synchronous second malignancies in 5% (n = 8) of the patients. Conclusion: Preoperative PET/CT should be considered in all EBCs> 2 cm as it upstages the disease and alters management in about 24% of these patients. Given its high specificity for axillary staging PET/CT, patients with PET-positive axilla can be subjected to axillary dissection and those with PET-negative axilla to sentinel lymph node biopsy. The yield and diagnostic accuracy of PET/CT is less for low-grade tumors <2 cm and with luminal A subtype.