Evaluation of a Recombinant Mouse X Pig Chimeric Anti-Porcine DEC205 Antibody Fused with Structural and Nonstructural Peptides of PRRS Virus

Activation of the immune system using antigen targeting to the dendritic cell receptor DEC205 presents great potential in the field of vaccination. The objective of this work was to evaluate the immunogenicity and protectiveness of a recombinant mouse x pig chimeric antibody fused with peptides of structural and nonstructural proteins of porcine respiratory and reproductive syndrome virus (PRRSV) directed to DEC205+ cells. Priming and booster immunizations were performed three weeks apart and administered intradermally in the neck area. All pigs were challenged with PRRSV two weeks after the booster immunization. Immunogenicity was evaluated by assessing the presence of antibodies anti-PRRSV, the response of IFN-γ-producing CD4+ cells, and the proliferation of cells. Protection was determined by assessing the viral load in the blood, lungs, and tonsils using qRT-PCR. The results showed that the vaccine exhibited immunogenicity but conferred limited protection. The vaccine group had a lower viral load in the tonsils and a significantly higher production of antibodies anti-PRRSV than the control group (p < 0.05); the vaccine group also produced more CD4+IFN-γ+ cells in response to peptides from the M and Nsp2 proteins. In conclusion, this antigenized recombinant mouse x pig chimeric antibody had immunogenic properties that could be enhanced to improve the level of protection and vaccine efficiency

Immune Response of Multiparous Hyper-Immunized Sows against Peptides from Non-Structural and Structural Proteins of PRRSV

The purpose of this study was to evaluate the humoral and cellular responses of commercial multiparous and hyper-immunized sows against peptides from non-structural (nsp) and structural proteins of porcine reproductive and respiratory syndrome virus (PRRSV). We selected sows with different numbers of parities from a commercial farm. Management practices on this farm include the use of the MLV commercial vaccine four times per year, plus two vaccinations during the acclimation period. The humoral response was evaluated via the antibody recognition of peptides from nsp and structural proteins, and the cellular response was assessed by measuring the frequency of peptide and PRRSV-specific IFN-gamma-secreting cells (IFNγ-SC). Our results show that sows with six parities have more antibodies against peptides from structural proteins than against peptides from nsp. The analysis of the cellular response revealed that the number of immunizations did not affect the frequency of IFNγ-SC and that the response was stronger against peptides from structural proteins (M protein) than against nsp (nsp2). In summary, these results demonstrate that multiparous, hyper-immunized sows have a stronger immune humoral response to PRRSV structural peptides than nsp, but no differences in IFNγ-SC against the same peptides were observed

A Retrospective Analysis of Porcine Circovirus Type 3 in Samples Collected from 2008 to 2021 in Mexico

Porcine circovirus type 3 (PCV3) is a nonenveloped virus of the Circoviridae family. This virus has been identified in pigs of different ages and pigs with several clinical manifestations of the disease or even in apparently healthy pigs. While PCV3 was first reported in 2015, several retrospective studies have reported the virus before that year. The earliest report indicates that PCV3 has been circulated in swine farms since 1996. In this study, we evaluated the presence of PCV3 in samples collected in Mexico in 2008, 2015, 2020, and 2021. This study assessed PCV3 DNA by qPCR and antibodies against CAP protein by indirect ELISA. The results showed that PCV3 (DNA and anti-CAP antibodies) was detected in the samples collected from 2008 to 2021. The highest prevalence was in 2008 (100%), and the lowest was in 2015 (negative). Genetic analysis of ORF2 showed that the virus identified belonged to genotype a, as most of the viruses identified thus far. PCV3 was detected in samples from piglets with respiratory signs and growth retardation, sows with reproductive failure, or asymptomatic piglets and sows. Pigs with respiratory signs, growth retardation, or reproductive failure had a higher prevalence of antibodies and qPCR-positive samples. In conclusion, this study showed that PCV3 has been circulating in Mexico since 2008 and that PCV3 DNA and antibodies were more prevalent in samples from pigs with clinical manifestations of diseases

A Retrospective Analysis of Porcine Circovirus Type 3 in Samples Collected from 2008 to 2021 in Mexico

Porcine circovirus type 3 (PCV3) is a nonenveloped virus of the Circoviridae family. This virus has been identified in pigs of different ages and pigs with several clinical manifestations of the disease or even in apparently healthy pigs. While PCV3 was first reported in 2015, several retrospective studies have reported the virus before that year. The earliest report indicates that PCV3 has been circulated in swine farms since 1996. In this study, we evaluated the presence of PCV3 in samples collected in Mexico in 2008, 2015, 2020, and 2021. This study assessed PCV3 DNA by qPCR and antibodies against CAP protein by indirect ELISA. The results showed that PCV3 (DNA and anti-CAP antibodies) was detected in the samples collected from 2008 to 2021. The highest prevalence was in 2008 (100%), and the lowest was in 2015 (negative). Genetic analysis of ORF2 showed that the virus identified belonged to genotype a, as most of the viruses identified thus far. PCV3 was detected in samples from piglets with respiratory signs and growth retardation, sows with reproductive failure, or asymptomatic piglets and sows. Pigs with respiratory signs, growth retardation, or reproductive failure had a higher prevalence of antibodies and qPCR-positive samples. In conclusion, this study showed that PCV3 has been circulating in Mexico since 2008 and that PCV3 DNA and antibodies were more prevalent in samples from pigs with clinical manifestations of diseases.This article is published as Reséndiz-Sandoval, Mónica, Verónica A. Vázquez-García, Kenneth Contreras-Vega, Edgar A. Melgoza-González, Verónica Mata-Haro, Luis Gimenez-Lirola, and Jesús Hernández. 2023. "A Retrospective Analysis of Porcine Circovirus Type 3 in Samples Collected from 2008 to 2021 in Mexico" Viruses 15, no. 11: 2225.doi:https://doi.org/10.3390/v15112225. Copyright: © 2023 by the authors. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/4.0/)

Development of a Multispecies Double-Antigen Sandwich ELISA Using N and RBD Proteins to Detect Antibodies against SARS-CoV-2

SARS-CoV-2 infects humans and a broad spectrum of animal species, such as pets, zoo animals, and nondomestic animals. Monitoring infection in animals is important in terms of the risk of interspecies transmission and the emergence of new viral variants. Economical, fast, efficient, and sensitive diagnostic tests are needed to analyze animal infection. Double-antigen sandwich ELISA has the advantage of being multispecies and can be used for detecting infections caused by pathogens that infect several animal hosts. This study aimed to develop a double-antigen sandwich ELISA using two SARS-CoV-2 proteins, N and RBD. We compared its performance, when using these proteins separately, with an indirect ELISA and with a surrogate virus neutralization test. Positive and negative controls from a cat population (n = 31) were evaluated to compare all of the tests. After confirming that double-antigen sandwich ELISA with both RBD and N proteins had the best performance (AUC= 88%), the cutoff was adjusted using positive and negative samples from cats, humans (n = 32) and guinea pigs (n = 3). The use of samples from tigers (n = 2) and rats (n = 51) showed good agreement with the results previously obtained using the microneutralization test. Additionally, a cohort of samples from dogs with unknown infection status was evaluated. These results show that using two SARS-CoV-2 proteins in the double-antigen sandwich ELISA increases its performance and turns it into a valuable assay with which to monitor previous infection caused by SARS-CoV-2 in different animal species

Antigen Targeting of Porcine Skin DEC205⁺ Dendritic Cells

Dendritic cell (DC) targeting by DEC205+ cells effectively promotes the internalization of antigens that may trigger a specific immune response. In this study, we evaluated the ability of a recombinant antibody, anti-DEC205 (rAb ZH9F7), to trigger cellular endocytosis in subpopulations of DCs and targeted cells after intradermal injection and subsequent migration toward lymph nodes. Furthermore, the cellular immune response was evaluated in pigs after intradermal application of the antigenized rAb ZH9F7 combined with porcine circovirus type 2 cap antigen (rAb ZH9F7-Cap). We demonstrated that rAb ZH9F7 recognized conventional type 1 and 2 DCs from the blood and skin and monocytes. It promoted receptor-mediated endocytosis and migration of cDCs and moDCs toward regional lymph nodes. Intradermal application of rAb ZH9F7-Cap induced a higher frequency of IFN-γ-secreting CD4+CD8+ T lymphocytes and antibodies against Cap protein than that in the control group. In conclusion, the rAb ZH9F7-Cap system promoted the target of skin cDC1 and cDC2, provoking migration to the regional lymph nodes and inducing a Th1 response, as evidenced by the proliferation of double-positive CD4+CD8+ T cells, which correlates with an enhanced ability to target the cDC1 subset both in vitro and in vivo

19n01, a broadly neutralizing antibody against omicron BA.1, BA.2, BA.4/5, and other SARS-CoV-2 variants of concern

Summary: This study reports the isolation and characterization of a human monoclonal antibody (mAb) called 19n01. This mAb was isolated by using single-cell RNAseq of B cells from donors infected with the ancestral strain. This mAb possesses a potent and broad capacity to bind and neutralize all previously circulating variants of concern (VOCs), including Omicron sublineages BA.1, BA.2, and BA.4/5. The pseudovirus neutralization assay revealed robust neutralization capacity against the G614 strain, BA.1, BA.2, and BA.4/5, with inhibitory concentration (IC50) values ranging from 0.0035 to 0.0164 μg/mL. The microneutralization assay using the G614 strain and VOCs demonstrated IC50 values of 0.013–0.267 μg/mL. Biophysical and structural analysis showed that 19n01 cross-competes with ACE2 binding to the receptor-binding domain (RBD) and the kinetic parameters confirmed the high affinity against the Omicron sublineages (KD of 61 and 30 nM for BA.2 and BA.4/5, respectively). These results suggest that the 19n01 is a remarkably potent and broadly reactive mAb