RESUMEN
Bovine gammaherpesvirus 4 (BoHV-4) is ubiquitous in cattle worldwide, and it has been detected in animals exhibiting broad clinical presentations. The virus has been detected in the United States since the 1970s; however, its clinical relevance remains unknown. Here, we determined the complete genome sequences of two contemporary BoHV-4 isolates obtained from respiratory (SD16-38) or reproductive (SD16-49) tract specimens and assessed clinical, virological, and pathological outcomes upon intranasal (IN) inoculation of calves with the respiratory BoHV-4 isolate SD16-38. A slight and transient increase in body temperature was observed in BoHV-4-inoculated calves. Additionally, transient viremia and virus shedding in nasal secretions were observed in all inoculated calves. BoHV-4 DNA was detected by nested PCR in the tonsil and regional lymph nodes (LNs) of calves euthanized on day 5 post-inoculation (pi) and in the lungs of calves euthanized on day 10 pi. Calves euthanized on day 35 pi harbored BoHV-4 DNA in the respiratory tract (turbinates, trachea, lungs), regional lymphoid tissues, and trigeminal ganglia. Interestingly, in situ hybridization revealed the presence of BoHV-4 DNA in nerve bundles surrounding the trigeminal ganglia and retropharyngeal lymph nodes (day 35 pi). No histological changes were observed in the respiratory tract (turbinate, trachea, and lung), lymphoid tissues (tonsil, LNs, thymus, and spleen), or central nervous tissues (olfactory bulb and trigeminal ganglia) sampled throughout the animal studies (days 5, 10, and 35 pi). This study contributes to the understanding of the infection dynamics and tissue distribution of BoHV-4 following IN infection in calves. These results suggest that BoHV-4 SD16-38 used in our study has low pathogenicity in calves upon intranasal inoculation.
Asunto(s)
Enfermedades de los Bovinos , Infecciones por Herpesviridae , Herpesvirus Bovino 1 , Herpesvirus Bovino 4 , Animales , Anticuerpos Antivirales , Bovinos , Infecciones por Herpesviridae/veterinaria , Herpesvirus Bovino 4/genética , Esparcimiento de VirusRESUMEN
AIM: To quantify the expression of Fc receptor (FcRn) and polymeric immunoglobulin receptor (pIgR) mRNA under a long-term influence of mycotoxin mycophenolic acid (MPA), which is used in human transplantation medicine due to its immunosuppressive properties and is a common contaminant in silage. METHOD: We applied 300 mg MPA/day in nine sheep for nine weeks and compared them with untreated animals (n=9). The expression level of Ig receptor mRNA was determined in eight different adult ovine tissues (liver, kidney, jejunum, ileum, spleen, thymus, mesenteric and pharyngeal lymph nodes). For a reliable and sensitive mRNA quantification of Ig receptor subtypes, a real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used with a relative- and tissue-specific efficiency corrected quantification model (REST). RESULTS: Each tissue exhibited an individual expression pattern of FcRn and pIgR mRNA. Both types of Ig receptors were highly expressed in the liver, kidney, and gastrointestinal tract. Medium-to-low expressions were found in the spleen, thymus, mesenteric and pharyngeal lymph nodes. FcRn mRNA was significantly down-regulated by MPA in the liver (p=0.02). After MPA treatment, a significant up-regulation of pIgR mRNA expression was observed in the ileum and liver (p=0.04 for both). Expression level of FcRn mRNA in the tissues in decreasing order was as follows: liver > kidney > jejunum > ileum > spleen > thymus > mesenterial lymph node > pharyngeal lymph node; whereas expression level for pIgR mRNA was the following: liver > kidney > jejunum > ileum > pharyngeal lymph node > spleen > thymus > mesenterial lymph node. CONCLUSION: The MPA exhibited immunomodulatory effects in the liver and ileum of treated sheep. Its possible immunosuppressive effects may be explained by lowering the level of FcRn expression in the liver, which resulted in a lower IgG serum-to-bile transport. However, MPA showed stimulatory effects on pIgR expression in the liver and ileum, suggesting good IgA and IgM transport in these tissues.