Heat-Priming during Somatic Embryogenesis Increased Resilience to Drought Stress in the Generated Maritime Pine (Pinus pinaster) Plants.

Drought stress is becoming the most important factor of global warming in forests, hampering the production of reproductive material with improved resilience. Previously, we reported that heat-priming maritime pine (Pinus pinaster) megagametophytes during SE produced epigenetic changes that generated plants better adapted to subsequent heat stress. In this work, we tested, in an experiment performed under greenhouse conditions, whether heat-priming will produce cross-tolerance to mild drought stress (30 days) in 3-year-old priming-derived plants. We found that they maintain constitutive physiological differences as compared to controls, such as higher proline, abscisic acid, starch, and reduced glutathione and total protein contents, as well as higher ΦPSII yield. Primed plants also displayed a constitutive upregulation of the WRKY transcription factor and the Responsive to Dehydration 22 (RD22) genes, as well as of those coding for antioxidant enzymes (APX, SOD, and GST) and for proteins that avoid cell damage (HSP70 and DHNs). Furthermore, osmoprotectants as total soluble sugars and proteins were early accumulated in primed plants during the stress. Prolongated water withdrawal increased ABA accumulation and negatively affected photosynthesis in all plants but primed-derived plants recovered faster than controls. We concluded that high temperature pulses during somatic embryogenesis resulted in transcriptomic and physiological changes in maritime pine plants that can increase their resilience to drought stress, since heat-primed plants exhibit permanent activation of mechanisms for cell protection and overexpression of stress pathways that pre-adapt them to respond more efficiently to soil water deficit.

Immunogenicity of a novel anti-allergic vaccine based on house dust mite purified allergens and a combination adjuvant in a murine prophylactic model.

The outer-membrane-derived proteoliposome (PL) of Neisseria meningitidis has been reported as a potent vaccine adjuvant, inducing a Th1-skewed response. This work aimed to assess the immunogenicity of a novel anti-allergic vaccine candidate based on allergens from Dermatophagoides siboney house dust mite and a combination adjuvant containing PL and Alum. In a preventative experimental setting, BALB/c mice were administered with three doses containing 2 µg of Der s1 and 0.4 µg Der s2 allergen, PL and Alum, at 7 days intervals, by subcutaneous route. Furthermore, mice were subjected to an allergen aerosol challenge for 6 consecutive days. Serum IgE, IgG1, and IgG2a allergen-specific antibodies were assessed by ELISA. Cytokine levels in supernatants of D. siboney stimulated lymphocyte cultures and in bronchoalveolar lavage (BAL) were measured by ELISA. Lung tissues were subjected to histological examination. The vaccine prevented the development of both, systemic (IgE) and local allergic responses (featuring lower IL-4, and IL-5 levels in BAL) upon allergen exposure by the inhalant route. Histological examination showed also a diminished allergic inflammatory response in the lungs. After the allergen challenge, cytokine levels in stimulated lymphocyte cultures showed lower values of IL-13 and augmented IFN-γ and IL-10. The vaccine induced a mixed IgG2a/IgG1 antibody response; although only IgG2a was PL-dependent. Both, IgG1/IgE and IgG2a/IgE ratios, showed significantly greater values in vaccinated mice. The findings support a preventative anti-allergic effect associated with the induction of a Th1-like IFN-γ/IL-10 response. IgG1/IgE and IgG2a/IgE ratios could be useful biomarkers for translation into clinical trials.

Elucidating the Role of Innate and Adaptive Immune Responses in the Pathogenesis of Canine Chronic Inflammatory Enteropathy-A Search for Potential Biomarkers.

Canine chronic inflammatory enteropathy (CIE) is one of the most common chronic gastrointestinal diseases affecting dogs worldwide. Genetic and environmental factors, as well as intestinal microbiota and dysregulated host immune responses, participate in this multifactorial disease. Despite advances explaining the immunological and molecular mechanisms involved in CIE development, the exact pathogenesis is still unknown. This review compiles the latest reports and advances that describe the main molecular and cellular mechanisms of both the innate and adaptive immune responses involved in canine CIE pathogenesis. Future studies should focus research on the characterization of the immunopathogenesis of canine CIE in order to advance the establishment of biomarkers and molecular targets of diagnostic, prognostic, or therapeutic utility.

N-antigenemia detection by a rapid lateral flow test predicts 90-day mortality in COVID-19: A prospective cohort study.

OBJECTIVES: To evaluate if the detection of N antigen of SARS-CoV-2 in plasma by a rapid lateral flow test predicts 90-day mortality in COVID-19 patients hospitalized at the wards. METHODS: The presence of N-antigenemia was evaluated in the first 36 hours after hospitalization in 600 unvaccinated COVID-19 patients, by using the Panbio COVID-19 Ag Rapid Test Device from Abbott (Abbott Laboratories Inc., Chicago, IL, USA). The impact of N-antigenemia on 90-day mortality was assessed by multivariable Cox regression analysis. RESULTS: Prevalence of N-antigenemia at hospitalization was higher in nonsurvivors (69% (82/118) vs. 52% (250/482); p < 0.001). The patients with N-antigenemia showed more frequently RNAemia (45.7% (148/324) vs. 19.8% (51/257); p < 0.001), absence of anti-SARS-CoV-2 N antibodies (80.7% (264/327) vs. 26.6% (69/259); p < 0.001) and absence of S1 antibodies (73.4% (240/327) vs. 23.6% (61/259); p < 0.001). The patients with antigenemia showed more frequently acute respiratory distress syndrome (30.1% (100/332) vs. 18.7% (50/268); p = 0.001) and nosocomial infections (13.6% (45/331) vs. 7.9% (21/267); p = 0.026). N-antigenemia was a risk factor for increased 90-day mortality in the multivariable analysis (HR, 1.99 (95% CI,1.09-3.61), whereas the presence of anti-SARS-CoV-2 N-antibodies represented a protective factor (HR, 0.47 (95% CI, 0.26-0.85). DISCUSSION: The presence of N-antigenemia or the absence of anti-SARS-CoV-2 N-antibodies after hospitalization is associated to increased 90-day mortality in unvaccinated COVID-19 patients. Detection of N-antigenemia by using lateral flow tests is a quick, widely available tool that could contribute to early identify those COVID-19 patients at risk of deterioration.

Correlation of basal cell carcinoma subtype with histologically confirmed subclinical extension during Mohs micrographic surgery: A prospective multicenter study.

BACKGROUND: Traditionally "aggressive" histologic subtypes (HSs) of basal cell carcinoma (BCC) are more likely to quantitatively exhibit subclinical extension (SCE), requiring more stages during Mohs micrographic surgery (MMS) and, therefore, larger margins upon excision. However, the tendency for SCE has never been compared between HSs of BCC in a prospective manner. OBJECTIVE: To prospectively correlate the HS of BCC with the likelihood of SCE as defined by the number of MMS stages required to clear the tumor. METHODS: In a prospective, multicenter study involving 17 Mohs surgeons in 16 different practices across the United States, data regarding 1686 cases of BCC undergoing MMS were collected. Patient demographics, tumor characteristics, number of MMS stages required for tumor clearance, and specific BCC subtypes noted on both index biopsy and the final MMS stage were recorded. RESULTS: Analysis of the average number of MMS stages for each HS required to clear tumor revealed 2 distinct degrees of SCE (P < .0001): high (higher than average) risk of SCE (1.9 stages, 1.0 SD) and low (lower than average) risk of SCE (1.6 stages, 0.9 SD). Subtypes of BCC within the high category were morpheaform (2.1), infiltrative (1.9), metatypical (1.9), mixed (1.8), and superficial (1.8). The low category included BCC subtypes of basosquamous (1.6), micronodular (1.6), nodular (1.6), and unspecified (1.5). Three hundred twenty-four cases (22.0%) manifested HS drift or a change in subtype from index biopsy to the final MMS stage. Superficial BCC was the only subtype that showed an increase in prevalence from index biopsy to the final MMS stage (from 16.0% to 25.8%; P < .0002). LIMITATIONS: HSs from index biopsy may not be representative of all HSs present, resulting in sampling bias. CONCLUSION: SCE of superficial BCC was as likely as SCE of BCC subtypes that are considered "aggressive" and are deemed "appropriate" for MMS by the appropriate use criteria. Our study also found that when HS drift occurs, the most likely subtype to extend subclinically is superficial BCC.

Changing Temperature Conditions during Somatic Embryo Maturation Result in Pinus pinaster Plants with Altered Response to Heat Stress.

Under the global warming scenario, obtaining plant material with improved tolerance to abiotic stresses is a challenge for afforestation programs. In this work, maritime pine (Pinus pinaster Aiton) plants were produced from somatic embryos matured at different temperatures (18, 23, or 28 °C, named after M18, M23, and M28, respectively) and after 2 years in the greenhouse a heat stress treatment (45 °C for 3 h/day for 10 days) was applied. Temperature variation during embryo development resulted in altered phenotypes (leaf histology, proline content, photosynthetic rates, and hormone profile) before and after stress. The thickness of chlorenchyma was initially larger in M28 plants, but was significantly reduced after heat stress, while increased in M18 plants. Irrespective of their origin, when these plants were subjected to a heat treatment, relative water content (RWC) and photosynthetic carbon assimilation rates were not significantly affected, although M18 plants increased net photosynthesis rate after 10 days recovery (tR). M18 plants showed proline contents that increased dramatically (2.4-fold) when subjected to heat stress, while proline contents remained unaffected in M23 and M28 plants. Heat stress significantly increased abscisic acid (ABA) content in the needles of maritime pine plants (1.4-, 3.6- and 1.9-fold in M18, M23, and M28 plants, respectively), while indole-3-acetic acid content only increased in needles from M23 plants. After the heat treatment, the total cytokinin contents of needles decreased significantly, particularly in M18 and M28 plants, although levels of active forms (cytokinin bases) did not change in M18 plants. In conclusion, our results suggest that maturation of maritime pine somatic embryos at lower temperature resulted in plants with better performance when subjected to subsequent high temperature stress, as demonstrated by faster and higher proline increase, lower increases in ABA levels, no reduction in active cytokinin, and a better net photosynthesis rate recovery.

Efficacy of Multivalent, Cochleate-Based Vaccine against Salmonella Infantis, S. Enteritidis and S. Typhimurium in Laying Hens.

Salmonella enterica is an important foodborne pathogen. Commercial poultry are the main reservoirs of Salmonella enterica, leading to the contamination of food and outbreaks in humans. The vaccination of chickens is one of the most important strategies to reduce the number of Salmonella in poultry farms. Unfortunately, commercial vaccines have not been fully effective in controlling the spread and do not contain all the Salmonella serovars that circulate on farms. In this study, we evaluate a new, cochleate-based, trivalent injectable vaccine against S. Enteritidis, S. Typhimurium and S. Infantis, describing the vaccine security, capacity to induce specific anti-Salmonella serovar IgY and the gene expression of immune markers related to CD4 and CD8 T-cell-mediated immunity. Efficacy was evaluated through oral challenges performed separately for each Salmonella serotype. The efficacy and safety of the trivalent vaccine was proven under controlled conditions. The vaccine has no local or systemic reactions or adverse effects on poultry performance related to the vaccine. The vaccine provided significantly increased serum IgY titer levels, significantly reduced Salmonella CFU/g present in the cecum and an increased CD4+/CD8+ ratio in vaccinated animals when challenged with S. Infantis, S. Enteritidis and S. Typhimurium. These results indicate that this new trivalent vaccine does not generate adverse effects in poultry and produces an increase in neutralizing antibodies against the three Salmonella serovars.

Effectiveness of a proteoliposome-based vaccine against salmonid rickettsial septicaemia in Oncorhynchus mykiss.

Salmonid rickettsial septicaemia (SRS) is a contagious disease caused by Piscirickettsia salmonis, an intracellular bacterium. SRS causes an estimated economic loss of $700 million USD to the Chilean industry annually. Vaccination and antibiotic therapy are the primary prophylactic and control measures used against SRS. Unfortunately, commercially available SRS vaccines have not been shown to have a significant effect on reducing mortality. Most vaccines contain whole inactivated bacteria which results in decreased efficacy due to the limited ability of the vaccine to evoke a cellular mediated immune response that can eliminate the pathogen or infected cells. In addition, SRS vaccine efficacy has been evaluated primarily with Salmo salar (Atlantic salmon). Vaccine studies using Oncorhynchus mykiss (rainbow trout) are scarce, despite SRS being the leading cause of infectious death for this species. In this study, we evaluate an injectable vaccine based on P. salmonis proteoliposome; describing the vaccine security profile, capacity to induce specific anti-P. salmonis IgM and gene expression of immune markers related to T CD8 cell-mediated immunity. Efficacy was determined by experimental challenge with P. salmonis intraperitoneally. Our findings indicate that a P. salmonis proteoliposome-based vaccine is able to protect O. mykiss against challenge with a P. salmonis Chilean isolate and causes a specific antibody response. The transcriptional profile suggests that the vaccine is capable of inducing cellular immunity. This study provides new insights into O. mykiss protection and the immune response induced by a P. salmonis proteoliposome-based vaccine.

Priming Maritime Pine Megagametophytes during Somatic Embryogenesis Improved Plant Adaptation to Heat Stress.

In the context of global climate change, forest tree research should be addressed to provide genotypes with increased resilience to high temperature events. These improved plants can be obtained by heat priming during somatic embryogenesis (SE), which would produce an epigenetic-mediated transgenerational memory. Thereby, we applied 37 °C or 50 °C to maritime pine (Pinus pinaster) megagametophytes and the obtained embryogenic masses went through the subsequent SE phases to produce plants that were further subjected to heat stress conditions. A putative transcription factor WRKY11 was upregulated in priming-derived embryonal masses, and also in the regenerated P37 and P50 plants, suggesting its role in establishing an epigenetic memory in this plant species. In vitro-grown P50 plants also showed higher cytokinin content and SOD upregulation, which points to a better responsiveness to heat stress. Heat exposure of two-year-old maritime pine plants induced upregulation of HSP70 in those derived from primed embryogenic masses, that also showed better osmotic adjustment and higher increases in chlorophyll, soluble sugars and starch contents. Moreover, ϕPSII of P50 plants was less affected by heat exposure. Thus, our results suggest that priming at 50 °C at the SE induction phase is a promising strategy to improve heat resilience in maritime pine.

VA-MENGOC-BC Vaccination Induces Serum and Mucosal Anti Neisseria gonorrhoeae Immune Responses and Reduces the Incidence of Gonorrhea.

BACKGROUND: Overall, there are over 30 different sexually transmitted infections with Neisseria gonorrhoeae being the third most frequent with a reported 78 million cases per year. Gonococcal infection causes genital inflammation, which can be a risk factor for others sexually transmitted infections, particularly human immunodeficiency virus. Gonorrhea is a treatable disease, but recently an increase in antibiotic resistance has been of concern. There are currently no vaccines available. However, parenteral vaccination with anti N. meningitidis serogroup B vaccine has been reported to decrease the incidence of gonococcal burden in New Zealand and in Cuba despite the fact that parenteral vaccination is not deemed to induce mucosal IgA. Here we explore possible mechanisms of protection against gonococcal infection through parenteral meningococcal B vaccination. METHODS: Ninety-two serum, saliva and oropharyngeal swabs samples of young adults (healthy and Neisseria carriers) of the internal higher school were obtained. They have been vaccinated with VA-MENGOC-BC (MBV) during their infancy and boosted with a third dose during this study. Serum and saliva samples were analyzed by ELISA and Western blot to measured IgG and IgA antibodies against N. meningitidis and N. gonorrhoeae antigens. N. meningitidis carriers were determined by standard microbiologic test. In addition, we reviewed epidemiologic data for N. meningitidis and N. gonorrhoeae infections in Cuba. RESULTS: Epidemiologic data show the influence of MBV over gonorrhea incidence suggesting to be dependent of sexual arrival age of vaccines but not over syphilis. Laboratorial data permit the detection of 70 and 22 noncarriers and carriers of N. meningitidis, respectively. Serum anti-MBV antigens (PL) responses were boosted by a third dose and were independent of carriage stages, but saliva anti-PL IgA responses were only present and were significant induced in carriers subjects. Carriers boosted with a third dose of MBV induced similar antigonococcal and -PL saliva IgA and serum IgG responses; meanwhile, serum antigonococcal IgG was significantly lower. In saliva, at least 2 gonococcal antigens were identified by Western blot. Finally, gonococcal-specific mucosal IgA antibody responses, in addition to the serum IgG antibodies, might contributed to the reduction of the incidence of N. gonorrhoeae. We hypothesize that this might have contributed to the observed reductions of the incidence of N. gonorrhoeae. CONCLUSION: These results suggest a mechanism for the influence of a Proteoliposome-based meningococcal BC vaccine on gonococcal incidence.

The global response to the COVID-19 pandemic: how have immunology societies contributed?

The COVID-19 pandemic is shining a spotlight on the field of immunology like never before. To appreciate the diverse ways in which immunologists have contributed, Nature Reviews Immunology invited the president of the International Union of Immunological Societies and the presidents of 15 other national immunology societies to discuss how they and their members responded following the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Respuesta anticlases mayores de anticuerpos humanos séricos en antisueros hiperinmunes obtenidos en carneros / Characterization of hyperimmune anti-human serum produced in sheep

Introducción: La inmunoelectroforesis es una técnica de precipitación que permite la caracterización de muestras biológicas complejas. En el Departamento de Inmunología del Instituto de Ciencias Básicas y Preclínicas Victoria de Girón se cuenta con un antisuero hiperinmune obtenido por inmunizaciones de carneros contra proteínas totales séricas humanas y con otro antisuero anti IgA de calostro humano. Objetivo: Identificar IgG, IgM e IgA en suero humano y determinar respuesta anti IgM humana en el antisuero anti IgA de calostro humano obtenido en carnero. Material y Métodos: Se realizó un estudio observacional, descriptivo y transversal desde noviembre de 2017 hasta junio de 2018. Se desarrolló una inmunoelectroforesis de suero humano normal empleando el antisuero hiperinmune. Resultados: Se identificaron IgG, IgM e IgA además de albúmina y otras fracciones proteicas y se determinó respuesta anti IgM humana en el antisuero anti IgA de calostro humano obtenido en carnero. Conclusiones: Este trabajo permitió identificar y determinar la respuesta anticlases mayores de inmunoglobulinas en la muestra de estudio(AU)

Introduction: Immunoelectrophoresis is a precipitation technique that allows the characterization of complex biological samples. The Immunology Department of the Institute of Basic and Pre-Clinical Sciences Victoria de Girón has a hyperimmune antiserum obtained by immunization of sheep against human serum total proteins and it also has an anti-human IgA antiserum obtained from human colostrum. Objective: The aim of this study was to identify IgG, IgM and IgA in human serum and to determine response to anti-human IgM in human colostral IgA with antiserum obtained in sheep. Material and Methods: An observational descriptive cross-sectional study was conducted from November 2017 to June 2018. Immunoelectrophoresis of normal human serum was performed using hyperimmune antiserum. Results: These procedures allowed to identify IgG, IgM and IgA in addition to albumin and other protein fractions and to determine response to anti-human IgM in human colostral IgA with antiserum obtained in sheep. Conclusions: This work allowed us to identify and determine significant anti-class responses of immunoglobulins in the sample studied(AU)

The immune profile induced is crucial to determine the effects of immunocastration over gonadal function, fertility, and GnRH-I expression.

PROBLEM: Immunocastration or vaccination against the GnRH-I hormone is a promising alternative to reproductive control in different animal species. Given the low immunogenicity of this hormone, the use of adjuvants becomes necessary. METHOD OF STUDY: This study evaluated the effects of three adjuvants that induce different immune response profiles over gonadal function, fertility, and expression of GnRH-I. Female mice (n = 6) were vaccinated at days 1 and 30 with a recombinant antigen for immunocastration and different adjuvants that induced preferentially Th1/Th2, Th2, and Th1 immune profiles. RESULTS: Th1/Th2 response is the most efficient to block reproductive activity in vaccinated animals, reducing the number of luteal bodies and pre-ovulatory follicles. Th2 and Th1/Th2 responses induced an increase in GnRH-I at the hypothalamus. CONCLUSION: The immune profile induced by different adjuvants is essential on the effects over fertility, gonadal function, and hypothalamic GnRH-I expression in immunocastrated animals.

Safety of a proteoliposome from Neisseria meningitides as adjuvant for a house dust mite allergy vaccine.

The proteoliposome (PL) of Neisseria meningitidis serogroup B has been reported as a safe and potent vaccine adjuvant, inducing a TH1-skewed response. The present study describes a pre-clinical safety evaluation of an allergy therapeutic vaccine candidate based on purified allergens from Dermatophagoides siboney house dust mite and PL as adjuvant, both components adsorbed onto aluminum hydroxide gel. Two separate studies of acute toxicity evaluation were performed in mice and rabbits, and two repeat-dose studies were conducted in non-sensitized and allergen-sensitized Balb/c mice, respectively. The study in sensitized mice intends to model a therapeutic setting. Aerosolized allergen challenge was used in both settings to model natural respiratory exposure. In the therapeutic setting, mice were administered with three doses containing 2 µg allergen at weekly intervals [subcutaneous route] and subsequently challenged with aerosolized allergen for 6 consecutive days. Parameters of general toxicity effects were assessed via measures of behavior, body weight, food and water consumption, and macroscopic evaluation of organs. Histological examination of organs and the injection site was performed. Potential immunotoxicity effects at the systemic level were assessed by blood eosinophil counting and serum allergen specific IgE by ELISA The vaccine did not produce general or functional toxic effects of significance, at a dose up to 100 µg allergen per kg body weight. An expected local reaction at the injection site was observed, which could be attributed mostly to the immunological effect of aluminum hydroxide. The models implemented here suggest an acceptable safety profile of this vaccine for testing in clinical trials of allergy immunotherapy.

The Hen's Egg Test on Chorioallantoic Membrane: An Alternative Assay for the Assessment of the Irritating Effect of Vaccine Adjuvants.

Local reactions are the most frequent adverse event associated with vaccines. Adjuvants are major constituents of many vaccines and they are frequently involved in these reactions, associated with their irritating effect and the stimulation of local inflammation. The hen's egg test on chorioallantoic membrane (HET-CAM) is an alternative toxicological method widely used to determine ocular irritation potential, but very few studies have demonstrated the utility of this method for assessing the irritant properties of vaccine adjuvants. In this work, known/experimental adjuvants were evaluated by both HET-CAM and an in vivo local toxicity study in mice to compare irritation scores to determine whether there was a correlation (Pearson test). Based on these data (r = 0.9034; P < 0.0001), the HET-CAM assay can be used as an alternate method for the prediction of the local toxicity potential of adjuvant candidates to be used in vaccines.

Survival rates and worker compensation expenses in a national cohort of Mexican workers with permanent occupational disability caused by diabetes.

BACKGROUND: Permanent occupational disability is one of the most severe consequences of diabetes that impedes the performance of usual working activities among economically active individuals. Survival rates and worker compensation expenses have not previously been examined among Mexican workers. We aimed to describe the worker compensation expenses derived from pension payments and also to examine the survival rates and characteristics associated with all-cause mortality, in a cohort of 34,014 Mexican workers with permanent occupational disability caused by diabetes during the years 2000-2013 at the Mexican Institute of Social Security. METHODS: A cross-sectional analysis study was conducted using national administrative records data from the entire country, regarding permanent occupational disability medical certification, pension payment and vital status. Survival rates were estimated using the Kaplan-Meier method. Multivariate Cox proportional hazard model was used to estimate adjusted hazard ratios (HR) and 95 % confidence intervals (95 % CI) in order to assess the cohort characteristics and all-cause mortality risk. Total expenses derived from pension payments for the period were accounted for in U.S. dollars (USD, 2013). RESULTS: There were 12,917 deaths in 142,725.1 person-years. Median survival time was 7.26 years. After multivariate adjusted analysis, males (HR, 1.39; 95 % CI, 1.29-1.50), agricultural, forestry, and fishery workers (HR, 1.41; 95 % CI, 1.15-1.73) and renal complications (HR, 3.49; 95 % CI, 3.18-3.83) had the highest association with all-cause mortality. The all-period expenses derived from pension payments amounted to $777.78 million USD (2013), and showed a sustained increment: from $58.28 million USD in 2000 to $111.62 million USD in 2013 (percentage increase of 91.5 %). CONCLUSIONS: Mexican workers with permanent occupational disability caused by diabetes had a median survival of 7.26 years, and those with renal complications showed the lowest survival in the cohort. Expenses derived from pension payments amounted to $ 777 million USD and showed an important increase from 2000 to 2013.

Effectiveness of an immunocastration vaccine formulation to reduce the gonadal function in female and male mice by Th1/Th2 immune response.

Immunocastration has emerged as an alternative to surgical castration in different animal species. This study examined the effectiveness of a new vaccine formulation for immunocastration using the biopolymer chitosan as adjuvant. First, female and male mice (n = 4), in three subsequent experiments were vaccinated at Days 1 and 30 of the study, to determine the immune response profile and gonadal alterations due to immunization. The results demonstrated that the vaccine was able to elicit strong antibody responses against native GnRH hormone (P < 0.01), with a T helper (Th) 1/Th2 immune response profile. Along with this, a suppression of gonadal activity with a decrease of luteal bodies (1.08 ± 0.22 and 4.08 ± 0.39) and antral follicles (1.17 ± 0.32 and 4.5 ± 0.38) in the ovaries of immunized females and control, respectively, and a reduction of seminiferous tubules size (142.3 ± 5.58 mm and 198.0 ± 6.11 mm) and germinal cellular layers (3.58 ± 0.26 and 5.08 ± 0.29) of immunized males and control animals, respectively, were observed (P < 0.01). Then, in a study of long-term immune response due to vaccination in female and male mice (n = 4) from two subsequent experiments, a suppression of gonadal function and an induction of a Th1/Th2 immune response was also observed, determined by both, immunoglobulin and cytokine profiles, which lasted until the end of the study (7 months; P < 0.01). The findings of this study have demonstrated that vaccination with a new immunocastration vaccine inducing a Th1/Th2 immune response against GnRH (P < 0.01) elicit a decrease of gonadal function in male and female mice (P < 0.01). Owing to long-term duration of the antibody levels generated, this vaccine formulation appears as a promising alternative for immunocastration of several animal species where long-lasting reproductive block is needed.