Astrovirus MLB2 (AstV-MLB2) is an emerging gastrointestinal virus causing meningitis and disseminated infections. Currently, there are no vaccine-based therapies available for AstV-MLB2. This study aims to develop multi-epitope vaccine models using candidate proteins from AstV-MLB2. Highly immunogenic epitopes (IC₅₀ < 200 μM) exhibiting conservation, antigenicity, and non-allergenicity were called from these proteins. Additionally, the selection criteria for epitopes were based on their potential to trigger immune cells and stimulate IFN-γ-mediated immune responses. The model vaccine constructs were designed from identified lead epitopes, along with immune-enhancer adjuvants and linker sequences. The proposed vaccine models were assessed for allergenicity, antigenicity, and structural integrity to ensure their safety and effectiveness. The binding potential of the vaccine models to HLA and TLR-4 immune cell receptors was evaluated to identify their capacity to stimulate immune responses. Among several raw constructs, MLB2-V1 and MLB2-V2 were identified as potential vaccine candidates due to their non-allergenic features, enhanced antigenic properties, and structural stability. Both these constructs were extensively evaluated and predicted to effectively bind to and interact with immune cell receptors, potentially triggering cellular and innate immune responses. Additionally, the prioritized constructs were deemed suitable for cloning and expression using recombinant DNA systems. The model vaccine constructs showed promise, warranting further investigation into their immune efficacy against MLB2-mediated infections through experimental assays and clinical trials.

The study evaluated the influence of dietary supplementation with nano-encapsulated cumin oil, B. subtilis, or a combination of both to mitigate the impacts of heat stress on the performance and health of growing rabbits. In the feeding trial, a total of eighty-four growing New Zealand White (35 days, 781.3 ± 1.8 g average body weight) were randomly distributed in a completely randomized design into four groups; each had 21 rabbits arranged in 7 replicates (3 rabbits each). The experiment lasted 42 days (35 days to 77 days). Growing rabbits received a basal diet (first group, CON) without additives, while the other groups were supplemented with nano-encapsulated cumin oil (NECO, 200 mg/kg), B. subtilis (BS, 500 mg/kg), or both (BSNO, 500 mg BS plus 200 mg/kg NECO). Adding BSNO significantly enhanced body weight gain, carcass weight, and feed conversion ratio and reduced mortality rate (p < 0.05). Additionally, the BSNO enhanced digestive system performance by increasing the secretion of trypsin enzymes, as well as nutrient digestibility, especially for protein and fiber (p < 0.05). Supplementing BSNO enhanced oxidative stability and immunity via higher levels of superoxide dismutase (SOD), IgA, IgG, triiodothyronine (T3), thyroxine (T4) and lower malondialdehyde (MDA) levels (p < 0.05), indicating a better ability to adapt to stress. During the examination of gut health, pathogenic bacteria counts decreased, as well as down-regulation of interleukin-6 (IL-6) gene expression and up-regulation of cationic amino acid transporter-1 (CAT-1), interleukin-10 (IL-10), and mucin-2 (MUC-2) gene expression (p < 0.05), supporting gut integrity. This study highlights the potential of mixing nano-encapsulated cumin oil and B. subtilis in growing rabbits’ diets as an effective strategy to counteract the negative effects of heat stress caused by high ambient temperatures.

Background: Immunophenotyping has been proven a valuable tool in diagnostic and research immunology laboratories to evaluate the immune status in health and disease. However, in some cases, cells cannot be analyzed immediately after separation and must be stored for later analysis. The present study was undertaken to investigate the impact of cryopreservation of camel PBMC on their vitality, recovery, shape, staining patterns with monoclonal antibodies and lymphocyte composition. Methods: Flow cytometry was employed to analyze cell apoptosis, necrosis, shape change, staining patterns with mAbs and cellular composition of freshly separated and cryopreserved camel PBMC. Result: The results showed similar lymphocytes and monocytes absolute numbers with comparable percentages of apoptotic and necrotic cells between fresh and preserved PBMC indicating no significant impact of cryopreservation on the recovery of camel PBMC. Although a cryopreservation-induced shape change was identified for camel lymphocytes, this change did not interfere with the identification of cryopreserved lymphocytes based on their SSC and FSC characteristics. In addition, the reactivity of camel PBMC with mAbs to the cell markers antigens CD45, CD44, CD11a, MHC-I, CD14, CD163 and CD172a remained unchanged for cryopreserved cells. However, mAbs to MHC-II and BAQ44A displayed modified binding to cryopreserved PBMC leading to significant changes in the positively stained B cells and increased MHC-II expression on monocytes. In conclusion, the results of the current study show that storing camel PBMC in cryopreservation media at -80 is an appropriate procedure for preserving the epitopes for all the used mAbs with modified binding to B cell markers.