Viral distribution and lesions in Kunming mice experimentally infected with porcine circovirus type 2b

Abstract

The viral distribution and lesions in Kunming mice experimentally infected with porcine circovirus type 2b (PCV-2b) were investigated. Seventy special pathogen free mice were divided into 2 groups with 35 mice in each group. The test group (TG) was infected with PCV-2b, the control group (CG) was inoculated with sterile cell cultures. Five mice in each group were sacrificed at 3, 7, 14, 21, 28, 35 and 42 dpi (day post infection), respectively. Necropsies were performed on all mice and tissues were collected for testing by histopathology, immunohistochemistry, transmission electron microscope (TEM) and polymerase chain reaction (PCR). Apoptosis and necrosis in lymphoid organs were observed in virus-infected mice, and became severe from 14 to 28 dpi. The proportion of PCV-2b antigen-positive cells was moderate in lung, heart, thymus, liver or kidney, and low in brain from TG. In spleen and cervical lymph node, the proportions of PCV-2b antigen-positive cells were low to high from 7 to 28 dpi, and moderate from 35 to 42 dpi. PCV-2b DNA was detected in all tissues examined in TG from 7 to 42 dpi. Viral inclusion bodies presented in the cytoplasm of lymphocytes, macrophages, hepatocytes, podocytes, neurocytes, spermatids and uterine epithelial cells in TG. In CG, no viruses and viral lesions were detected. PCV-2b could replicate in mice, and PCV-2b associated lesions in mice were similar to those observed in pigs. The present results indicate that it is possible to use Kunming mouse as an animal model for PMWS research.

Rapidly expanding genetic diversity and host range of the Circoviridae viral family and other Rep encoding small circular ssDNA genomes

“…Sequence analysis showed that the PCV2 sequences from rodents were similar to those from pigs at the two farms, belonging to the PCV2b genogroup with low levels of nucleotide differences (Lorincz et al, 2010). Low level PCV2b replication could also be demonstrated in inoculated mice (Cságola et al, 2008; Deng et al, 2011). A report of PCV2 infection in cows found PCV2 DNA in 6/100 lung tissue samples from cows with respiratory disease and in 4/30 aborted bovine fetuses (Nayar et al, 1999).…”

Enhancing mucosal immunity in mice by recombinant adenovirus expressing major epitopes of porcine circovirus-2 capsid protein delivered with cytosine-phosphate-guanosine oligodeoxynucleotides

“…BALB/c mice were used as an animal model as previously described [6,7,18,19]. A total of 175 specific pathogen-free (SPF) female BALB/c mice 6 to 8 weeks old were obtained from the Experimental Animal Center of Henan Province (China).…”

Vertical transmission of porcine circovirus 2b (PCV2b) to mouse fetuses in maternal uterus by artificial insemination with semen from PCV2b-infected male mouse

“…Using the PCV2b-specific primers (5' -GGAGCTTCCAATCTCCC-3' , 5'-TAGGAGCTCCACACTCC-3'), the PCV2b DNA in mice was detected by PCR following the methods described in a previous study (9).…”

“…The primary mouse anti-PCV2b sera preparation was as described in our previous study (9), and then sections were incubated with a 1:400 dilution of primary mouse antiPCV2b sera at 37 °C for 2 h. Following this, a 1:50 dilution of secondary anti-mouse IgG antibody with fluorescein (Zhongshan Golden Bridge Co. Ltd., Beijing, China) was added at 37 °C for 1 h; finally, it was photographed under a fluorescence microscope (Olympus, Tokyo, Japan).…”