CD154 Expression Indicates T Cell Activation Following Tetanus Toxoid Vaccination of Horses

Bacillus toyonensis amplifies the immunogenicity of an experimental recombinant tetanus vaccine in horses

Probiotic microorganisms can stimulate an immune response and increase the efficiency of vaccines. For example, Bacillus toyonensis is a nonpathogenic, Gram-positive bacterium that has been used as a probiotic in animal supplementation. It induces immunomodulatory effects and increases the vaccine response in several species. This study aimed to evaluate the effect of B. toyonensis supplementation on the modulation of the immune response in horses vaccinated with recombinant Clostridium tetani toxin. Twenty horses were vaccinated twice, with an interval of 21 days between doses, and equally divided into two groups: the first group was supplemented orally for 42 days with feed containing viable spores of B. toyonensis (1 × 108) mixed with molasses (40 ml), starting 7 days before the first vaccination; the second (control) group received only feed mixed with molasses, starting 7 days before the first vaccination. Serum samples were collected to evaluate the humoral immune response using an in-house indirect enzyme-linked immunosorbent assay (ELISA), and peripheral blood mononuclear cells (PBMCs) were collected to evaluate cytokine transcription (qPCR). For the specific IgG-anti-rTENT titer, the supplemented group had ELISA values that were four times higher than those of the control group (p < 0.05). The supplemented group also showed higher ELISA values for the IgGa and IgGT sub-isotypes compared to the control group. In PBMCs stimulated with B. toyonensis, relative cytokine transcription of the supplemented group showed 15-, 8-, 7-, and 6-fold increases for IL1, TNFα, IL10 and IL4, respectively. When stimulated with a vaccine antigen, the supplemented group showed 1.6-, 1.8-, and 0.5-fold increases in IL1, TNFα, and IL4, respectively, compared to the control group. Horses supplemented with B. toyonensis had a significantly improved vaccine immune response compared to those in the control group, which suggests a promising approach for improving vaccine efficacy with probiotics.

Aspergillus fumigatus binding IgA and IgG1 are increased in bronchoalveolar lavage fluid of horses with neutrophilic asthma

Introduction

Equine asthma (EA) is a common lower airway disease in horses, but whether its pathogenesis is allergic is ambiguous. Extrinsic stimuli like hay dust induce acute exacerbation of clinical signs and sustained local neutrophilic inflammation in susceptible horses. Aspergillus fumigatus is an EA stimulus, but it is unclear if it merely acts as an IgE-provoking allergen. We aimed to comprehensively analyze immunoglobulin (Ig) isotypes in EA, elucidating their binding to different A. fumigatus antigens, and their quantities systemically in serum and locally in bronchoalveolar lavage fluid (BALF).

Methods

Serum and BALF from healthy horses (HE, n = 18) and horses with mild-moderate asthma (MEA, n = 20) or severe asthma (SEA, n = 24) were compared. Ig isotype (IgG1, IgG3/5, IgG4/7, IgG6, IgA, and IgE) binding to nine antigens (A. fumigatus lysate, and recombinant Asp f 1, Asp f 7, Asp f 8, dipeptidyl-peptidase 5, class II aldolase/adducin domain protein, glucoamylase, beta-hexosaminidase, and peptide hydrolase) was compared by enzyme-linked immunosorbent assays. Total Ig isotype contents were determined by bead-based assays.

Results

MEA and SEA differed from HE but hardly from each other. Compared to HE, asthmatic horses showed increased anti-A. fumigatus binding of IgG (BALF and serum) and IgA (BALF). Serum and BALF IgE binding and total IgE contents were similar between HE and EA. Single antigens, as well as A. fumigatus lysate, yielded similar Ig binding patterns. Serum and BALF IgG1 binding to all antigens was increased in SEA and to several antigens in MEA. Serum IgG4/7 binding to two antigens was increased in SEA. BALF IgA binding to all antigens was increased in SEA and MEA. Total BALF IgG1 and IgG4/7 contents were increased in SEA, and serum IgG4/7 content was increased in MEA compared to HE. Yet, total isotype contents differentiated EA and HE less clearly than antigen-binding Ig.

Discussion

A. fumigatus immunogenicity was confirmed without identification of single dominant antigens here. A. fumigatus provoked elevated BALF IgG1 and IgA binding, and these isotypes appear relevant for neutrophilic EA, which does not support allergy. BALF Ig isotype differentiation beyond IgE is crucial for a comprehensive analysis of immune responses to fungi in EA pathogenesis.

Monoclonal antibody development advances immunological research in horses

Host immune analyses require specific reagents to identify cellular and soluble components of the immune system. These immune reagents are often species-specific. For horses, various immunological tools have been developed and tested by different initiatives during the past decades. This article summarizes the development of well characterized monoclonal antibodies (mAbs) for equine immune cells, immunoglobulin isotypes, cytokines, and chemokines.

Investigation of activation-induced markers (AIM) in porcine T cells by flow cytometry

Activation-induced markers (AIMs) are frequently analyzed to identify re-activated human memory T cells. However, in pigs the analysis of AIMs is still not very common. Based on available antibodies, we designed a multi-color flow cytometry panel comprising pig-specific or cross-reactive antibodies against CD25, CD69, CD40L (CD154), and ICOS (CD278) combined with lineage/surface markers against CD3, CD4, and CD8α. In addition, we included an antibody against tumor necrosis factor alpha (TNF-α), to study the correlation of AIM expression with the production of this abundant T cell cytokine. The panel was tested on peripheral blood mononuclear cells (PBMCs) stimulated with phorbol 12-myristate 13-acetate (PMA)/ionomycin, Staphylococcus enterotoxin B (SEB) or PBMCs from African swine fever virus (ASFV) convalescent pigs, restimulated with homologous virus. PMA/ionomycin resulted in a massive increase of CD25/CD69 co-expressing T cells of which only a subset produced TNF-α, whereas CD40L expression was largely associated with TNF-α production. SEB stimulation triggered substantially less AIM expression than PMA/ionomycin but also here CD25/CD69 expressing T cells were identified which did not produce TNF-α. In addition, CD40L-single positive and CD25+CD69+CD40L+TNF-α- T cells were identified. In ASFV restimulated T cells TNF-α production was associated with a substantial proportion of AIM expressing T cells but also here ASFV-reactive CD25+CD69+TNF-α- T cells were identified. Within CD8α+ CD4 T cells, several CD25/CD40L/CD69/ICOS defined phenotypes expanded significantly after ASFV restimulation. Hence, the combination of AIMs tested will allow the identification of primed T cells beyond the commonly used cytokine panels, improving capabilities to identify the full breadth of antigen-specific T cells in pigs.

The quest for nanoparticle-powered vaccines in cancer immunotherapy

Despite recent advancements in cancer treatment, this disease still poses a serious threat to public health. Vaccines play an important role in preventing illness by preparing the body's adaptive and innate immune responses to combat diseases. As our understanding of malignancies and their connection to the immune system improves, there has been a growing interest in priming the immune system to fight malignancies more effectively and comprehensively. One promising approach involves utilizing nanoparticle systems for antigen delivery, which has been shown to potentiate immune responses as vaccines and/or adjuvants. In this review, we comprehensively summarized the immunological mechanisms of cancer vaccines while focusing specifically on the recent applications of various types of nanoparticles in the field of cancer immunotherapy. By exploring these recent breakthroughs, we hope to identify significant challenges and obstacles in making nanoparticle-based vaccines and adjuvants feasible for clinical application. This review serves to assess recent breakthroughs in nanoparticle-based cancer vaccinations and shed light on their prospects and potential barriers. By doing so, we aim to inspire future immunotherapies for cancer that harness the potential of nanotechnology to deliver more effective and targeted treatments.

Immunoproteomics reveal increased serum IgG3/5 binding to Dermatophagoides and yeast protein antigens in severe equine asthma in a preliminary study

Introduction

Severe equine asthma (SEA) is a common, chronic respiratory disease of horses characterized by hyperreactivity to hay dust which has many similarities to severe neutrophilic asthma in humans. SEA-provoking antigens have not been comprehensively characterized, but molds and mites have been suggested as relevant sources. Here, we identified relevant antigen candidates using immunoproteomics with IgG isotype-binding analyses.

Methods

Proteins from Dermatophagoides pteronyssinus (Der p) were separated by two-dimensional gel electrophoresis followed by immunoblotting (2D immunoblots) resulting in a characteristic pattern of 440 spots. After serum incubation, antibody (Ig)-binding of all Ig (Pan-Ig) and IgG isotypes (type-2-associated IgG3/5, type-1-associated IgG4/7) was quantified per each spot and compared between asthmatic and healthy horses' sera (n=5 per group).

Results

Ig binding differences were detected in 30 spots. Pan-Ig binding was higher with asthmatics compared to healthy horses' sera on four spots, and IgG3/5 binding was higher on 18 spots. Small IgG4/7 binding differences were detected on 10 spots with higher binding with asthmatics' sera on four but higher binding with healthy horses' sera on six spots. Proteins from the spots with group differences including mite and yeast proteins were identified by liquid chromatography mass spectrometry. The latter likely originated from the feeding substrate of the Der p culture. Prioritized antigen candidates amongst the proteins identified were Der p 1, Der p 11, group 15 allergens, myosin heavy chain, and uncharacterized Der p proteins. Additionally, yeast enolases, alcohol dehydrogenase (ADH), phosphoglycerate kinase (PGK), glyceraldehyde-3-phosphate dehydrogenase, and heat shock proteins were prioritized. Eleven antigen candidates were tested for confirmation by ELISAs using the respective proteins separately. Differences in asthmatics vs. healthy horses' serum Ig binding to Der p 1, Der p 18, and three yeast enzymes (enolase, ADH, and PGK) confirmed these as promising antigens of immune responses in SEA.

Discussion

Antigens with relevance in SEA were newly identified by immunoproteomics, and yeast antigens were considered for SEA for the first time. Serum IgG3/5 binding to relevant antigens was increased in SEA and is a novel feature that points to increased type-2 responses in SEA but requires confirmation of the corresponding cellular responses.

Canine peripheral blood TCRαβ T cell atlas: Identification of diverse subsets including CD8A+ MAIT-like cells by combined single-cell transcriptome and V(D)J repertoire analysis

The dog is valued as a companion animal and increasingly recognized as a model for human disorders. Given the importance of T cells in health and disease, comprehensive knowledge of canine T cells can contribute to our understanding of pathogenesis mechanisms and inform the development of new treatment strategies. However, the diversity of canine T cells is still poorly understood mainly due to the lack of species-reactive antibodies for use in flow cytometry. The aim of this study was to generate a detailed atlas of peripheral blood TCRαβ⁺ T cells of healthy dogs using single-cell RNA-sequencing (scRNAseq) combined with immune repertoire sequencing. A total of 22 TCRαβ⁺ T cell clusters were identified, which were classified into three major groups: CD4-dominant (11 clusters), CD8A-dominant (8 clusters), and CD4/CD8A-mixed (3 clusters). Based on differential gene expression, distinct differentiation states (naïve, effector, memory, exhausted) and lineages (e.g. CD4 T helper and regulatory T cells) could be distinguished. Importantly, several T cell populations were identified, which have not been described in dogs before. Of particular note, our data provide first evidence for the existence of canine mucosa-associated invariant T cell (MAIT)-like cells, representing one of three newly identified FCER1G⁺ innate-like CD8A⁺ T cell populations in the peripheral blood of healthy dogs. In conclusion, using scRNAseq combined with immune repertoire sequencing we were able to resolve canine TCRαβ⁺ T cell populations at unprecedented resolution. The peripheral blood TCRαβ⁺ T cell atlas of healthy dogs generated here represents an important reference data set for future studies and is of relevance for identifying new targets for T cell-specific therapies.

Comprehensive Flow Cytometric Characterization of Bronchoalveolar Lavage Cells Indicates Comparable Phenotypes Between Asthmatic and Healthy Horses But Functional Lymphocyte Differences

Equine asthma (EA) is a highly relevant disease, estimated to affect up to 20% of all horses, and compares to human asthma. The pathogenesis of EA is most likely immune-mediated, yet incompletely understood. To study the immune response in the affected lower airways, mixed leukocytes were acquired through bronchoalveolar lavage (BAL) and the cell populations were analyzed on a single-cell basis by flow cytometry (FC). Samples of 38 horses grouped as respiratory healthy or affected by mild to moderate (mEA) or severe EA (sEA) according to their history, clinical signs, and BAL cytology were analyzed. Using FC, BAL cells and PBMC were comprehensively characterized by cell surface markers ex vivo. An increased percentage of DH24A⁺ polymorphonuclear cells, and decreased percentages of CD14⁺ macrophages were detected in BAL from horses with sEA compared to healthy horses or horses with mEA, while lymphocyte proportions were similar between all groups. Independently of EA, macrophages in BAL were CD14⁺CD16⁺, which contrasts the majority of CD14⁺CD16^- classical monocytes in PBMC. Percentages of CD16-expressing BAL macrophages were reduced in BAL from horses with sEA compared to healthy horses. While PBMC lymphocytes predominantly contain CD4⁺ T cells, B cells and few CD8⁺ T cells, BAL lymphocytes comprised mainly CD8⁺ T cells, fewer CD4⁺ T cells and hardly any B cells. These lymphocyte subsets’ distributions were similar between all groups. After PMA/ionomycin stimulation in vitro, lymphocyte activation (CD154 and T helper cell cytokine expression) was analyzed in BAL cells of 26 of the horses and group differences were observed (p=0.01–0.11). Compared to healthy horses’ BAL, CD154⁺ lymphocytes from horses with mEA, and CD4⁺IL-17A⁺ lymphocytes from horses with sEA were increased in frequency. Activated CD4⁺ T helper cells were more frequent in asthmatics’ (mEA, sEA) compared to healthy horses’ PBMC lymphocytes. In summary, FC analysis of BAL cells identified increased polymorphonuclear cells frequencies in sEA as established, while macrophage percentages were mildly reduced, and lymphocyte populations remained unaffected by EA. Cytokine production differences of BAL lymphocytes from horses with sEA compared to healthy horses’ cells point towards a functional difference, namely increased local type 3 responses in sEA.