A Gamma-adapted subunit vaccine induces broadly neutralizing antibodies against SARS-CoV-2 variants and protects mice from infection.

In the context of continuous emergence of SARS-CoV-2 variants of concern (VOCs), one strategy to prevent the severe outcomes of COVID-19 is developing safe and effective broad-spectrum vaccines. Here, we present preclinical studies of a RBD vaccine derived from the Gamma SARS-CoV-2 variant adjuvanted with Alum. The Gamma-adapted RBD vaccine is more immunogenic than the Ancestral RBD vaccine in terms of inducing broader neutralizing antibodies. The Gamma RBD presents more immunogenic B-cell restricted epitopes and induces a higher proportion of specific-B cells and plasmablasts than the Ancestral RBD version. The Gamma-adapted vaccine induces antigen specific T cell immune responses and confers protection against Ancestral and Omicron BA.5 SARS-CoV-2 challenge in mice. Moreover, the Gamma RBD vaccine induces higher and broader neutralizing antibody activity than homologous booster vaccination in mice previously primed with different SARS-CoV-2 vaccine platforms. Our study indicates that the adjuvanted Gamma RBD vaccine is highly immunogenic and a broad-spectrum vaccine candidate.

Estrogens receptors, nuclear coactivator 1 and ligand-dependent corepressor expression are altered early during induced ovarian follicular persistence in dairy cattle.

Failure of ovulation can lead to follicular persistence, one of the main components of the pathogenesis of cystic ovarian disease (COD) in dairy cattle. Follicular persistence causes the permanence of a functional follicular structure in the ovary, which alters the cyclicity of the female and causes infertility. The aim of the present study was to evaluate the expression of estrogen receptors (ESR) 1 and 2, and the coregulatory proteins NCOA1, NRIP1 and LCOR by immunohistochemistry, in antral and preovulatory/persistent follicles in a model of follicular persistence induced by low levels of progesterone, to detect incipient changes during COD development, on the expected day of ovulation (P0) and after 5 (P5), 10 (P10) and 15 (P15) days of follicular persistence. Twenty-five Holstein cows were used, which were distributed in 5 groups: control group (n = 5), group P0 (n = 5), group P5 (n = 5), group P10 (n = 5), group P15 (n = 5). ESR1 expression was lower in antral follicles of the P5 (theca), P10 and P15 (theca and granulosa) groups relative to the control group (p < 0.05), and also lower in granulosa cells of persistent follicles of the P5, P10 and P15 groups than in dominant follicles of the control group (p < 0.05), without differences in theca cells. ESR2 expression showed no differences between groups. The ESR1:ESR2 balance favored ESR2 expression along the development of persistent follicles, as from 5 days of persistence (p < 0.05). NCOA1 expression was higher in granulosa cells of both antral and persistent follicles from the P0 group relative to the P5 and P10 groups, but showed no differences with the control and P15 groups (p < 0.05). Theca cells of antral and persistent follicles showed higher expression in the P0 and P15 groups in relation to the control, P5 and P10 groups (p < 0.05). No differences were detected for NRIP1 in antral, dominant and persistent follicles between groups. LCOR expression showed a decrease in granulosa cells of antral follicles from all persistence groups relative to the control group (p < 0.05). In theca cells, antral follicles of the P10 group showed lower LCOR expression than the control group (p < 0.05). LCOR expression was similar for dominant and persistent follicles. Considering that the ESR1:ESR2 balance favored ESR2 expression along the development of persistent follicles, as well as the decreased LCOR and NCOA1 expression, we may assume that, at the early stages of persistence, there is a negative regulation of ESR transcription. This coincides with the effects of estrogens through ESR on proliferation and apoptosis among other processes that favor follicular persistence. The results obtained provide relevant information in the knowledge of local events during the development of follicular persistence that could explain the failures in the reversion of the disease through hormonal treatments and the high recurrence rates reported for COD. In addition, it contributes to the study and identification of possible therapeutic targets, for the design of new treatments.

Association between heat stress during intrauterine development and the expression and regulation of ovarian steroid hormone receptors in adult Holstein cows.

CONTEXT: Dairy cattle experience stressful environmental situations that affect production. Heat stress during gestation can influence the intrauterine development of offspring, resulting in long-term damage that can affect the reproductive life of the adult offspring. AIM: The aim of the present study was to evaluate changes in the expression and regulation of steroid hormone receptors in the ovary of Holstein cows gestated under different temperature-humidity index (THI) during their in utero development. METHODS: Animals were classified by their exposure to temperature-humidity index (THI) ≥72 during their development in utero according to date of birth or date of effective service of their mother. This study was not carried out under controlled conditions, but the conditions to which the cows were naturally exposed during their development were considered retrospectively, controlling the variables in the statistical analyses (age as a covariate, dairy farm as a random factor). Gestation was divided into two periods (P1=days 0-150; and P2=day 151 to calving) and three trimesters (T1=days 0-90; T2=days 91-180; and T3=day 181 to calving), and the exposure to THI ≥72 was calculated in each one. The following characteristics were evaluated: gene expression of estrogen receptor (ESR) 1, ESR2 and progesterone receptor (PGR), CpG methylation in the 5'UTR of ESR1 and ESR2, and protein expression of ESR1, ESR2, PGR and coregulatory proteins in the dominant follicles of daughter cows in adulthood. KEY RESULTS: We found associations between heat stress variables during gestation and the methylation status of CpG sites in the 5'UTR of ESR1 and ESR2 in dominant follicles. Results also showed association between exposure to high THI values during intrauterine development and expression of ESR1, ESR2 and PGR and coregulatory proteins in dominant follicles of adult cows. CONCLUSIONS: These results provide novel information about the impact of prenatal heat stress on molecular aspects at the ovary level in the offspring, during their adult life, which probably impacts the reproductive aspects of the herd.

Characterization of an incipient granulosa cell tumour in a Holstein cow: Steroid hormone receptors and coregulators expression.

The objective of this study was to describe a case of a granulosa cell tumour (GCT) of incipient formation and to characterize it by its immunohistochemical pattern and hormonal profile. The case presented corresponds to a 7-year-old Holstein cow without reproductive disorders. No alterations were observed at rectal palpation, neither in the ultrasonography nor in the hormonal profile. A GCT concomitant with normal follicular development was diagnosed. Through a panel of immunohistochemical markers, a highly differentiated pattern could be determined in the GCT, which preserves the expression of steroid receptors (ESR1, ESR2 and PR) typical of granulosa cells, but does not express the enzymes for the synthesis of androgens (CYP17A1) and oestrogens (CYP19A1). In addition, the expression of co-regulators of steroid hormone receptors and neuroendocrine markers was described for the first time in a GCT in cattle. These results increase the information about GCTs in cattle before the ovarian function is compromised.

Non-clinical safety assessment and in vivo biodistribution of CoviFab, an RBD-specific F(ab')2 fragment derived from equine polyclonal antibodies.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has required the urgent development of new therapies, among which passive immunotherapy is contemplated. CoviFab (INM005) is a RBD-specific F(ab')2 fragment derived from equine polyclonal antibodies. We investigate their preclinical security and biodistribution by in vivo and ex vivo NIR imaging after intravenous administration of a dose of 4 mg/kg at time 0 and 48 h. Images were taken at 1, 12, 24, 36, 48, 49, 60, 72, 84, 96, 108, 120, 132 and 144 h after the first intravenous injection. At 96 and 144 h, mice were sacrificed for haematology, serum chemistry, clinical pathology, histopathology and ex vivo imaging. The biodistribution profile was similar in all organs studied, with the highest fluorescence at 1 h after each injection, gradually decreasing after that each one and until the end of the study (144 h). The toxicology study revealed no significant changes in the haematology and serum chemistry parameters. Further, there were no changes in the gross and histological examination of organs. Nonclinical data of the current study confirm that CoviFab is safe, without observable adverse effects in mice. Furthermore, we confirm that bioimaging studies are a useful approach in preclinical trials to determine biodistribution.

Association between heat stress during intrauterine development and the calving-to-conception and calving-to-first-service intervals in Holstein cows.

Heat stress has been widely studied in relation to its effects on the production and reproduction of dairy cattle. However, the long-term effects of heat stress during intrauterine development on adult cows have been scarcely considered. Thus, the aim of this study was to evaluate possible changes in the reproductive performance of Holstein cows gestated under different values of the Temperature-Humidity Index (THI) during their intrauterine development. Data collected from a database of reproductive and productive records of 10,790 Holstein cows from the central region of Argentina and the THI data from the agrometeorological station of the Instituto Nacional de Tecnología Agropecuaria (INTA) EEA Rafaela, Santa Fe, Argentina, were used. The gestation of the cows evaluated was divided into trimesters, in which the highest THI cycles (sum of three or more consecutive days of exposure to a THI ≥72 during each trimester) and number of days with a THI ≥ 72 were calculated. The calving-to-conception and calving-to-first-service intervals of the cows evaluated were considered as reproductive variables associated with their first lactation. Generalized Linear Mixed Models were used, considering the cow's dairy farm as a random factor within the model. The exposure of the animals to environments with a THI ≥72 during the first trimester of gestation had a negative impact on the reproductive efficiency parameters analyzed. The results obtained indicate that the exposure of pregnant females to high THI values has a long-term impact on their daughters, which may contribute to a decrease in their reproductive performance, possibly through inherited epigenetic characteristics that remain in later generations through fetal programming.

Changes in the Proliferation/Apoptosis Balance in the Bovine Ovary: A Key Early Event in Follicular Persistence.

The objective of this work was to evaluate proliferation and apoptosis in the bovine ovary in a model of follicular persistence induced by low levels of progesterone to detect incipient changes during cystic ovarian disease development on the expected day of ovulation (day 0) and after 5, 10, and 15 days of follicular persistence. We analyzed cell proliferation by evaluating the expression of Ki-67 and apoptosis by evaluating caspase-3, BAX, and BCL2 expression. Proliferation was similar in the granulosa and theca cells of antral follicles in the P0 group (treated with progesterone up to the expected day of ovulation) and in the control group. A decrease in cell proliferation was detected after 5 days of persistence (P5) in relation to P0 (p < 0.05). Similar changes were found in the granulosa cells of the persistent follicles in relation to the control group (p < 0.05). Caspase-3 expression was similar in granulosa cells of antral follicles at early stages of persistence, with an increase after 15 days of persistence (p < 0.05). In the granulosa cells of group P10 (10 days of persistence), caspase-3 expression was reduced relative to that of antral follicles from the control group (p < 0.05). BCL2 expression was higher in granulosa cells of the persistent follicles of group P0 relative to the control follicles, with no changes in BAX expression, which was increased in persistent follicles of group P15 (p < 0.05). Similar results were observed in theca cells at initial stages of persistence. The results show that, initially, proliferation is maintained with low apoptosis and an increase in cell survival.