Expression of EV71-VP1, PSGL-1 and SCARB2 in Tissues of Infants with Brain Stem Encephalitis / 法医学杂志

OBJECTIVE@#To understand the correlation of enterovirus 71 (EV71), P-selectin glycoprotein ligand-1 (PSGL-1), and scavenger receptor B2 (SCARB2) and to explore the possible pathway and mechanism of EV71 infection by observing the expression of EV71, PSGL-1 and SCARB2 in tissues of infants with brain stem encephalitis.@*METHODS@#The organs and tissues of infants with EV71-VP1 positivity in their brain stems were chosen. Expression and distribution of EV71-VP1, PSGL-1, and SCARB2 were detected and compared by immunohistochemistry.@*RESULTS@#Strong staining of EV71 -VP1 was observed in the neuron, glial cells, the inflammatory cells of perivascular cuffing, parietal cells of the gastric fundus gland while alveolar macrophages, intestinal gland epithelium cells, mucosa lymphoid nodule and lymphocyte of palatine tonsil showed moderate staining and weak staining were displayed in mesenteric lymph nodes and lymphocyte of spleen. PSGL-1 expression was detected in parietal cells of the gastric fundus gland, tonsillar crypt squamous epithelium, alveolar macrophages and leukocytes in each tissue. SCARB2 expression was observed in all the above tissues except the intestines and spleen.@*CONCLUSION@#The distribution of EV71 correlates with SCARB2 expression. SCARB2 plays an important role in virus infection and replication. Stomach may be an important site for EV71 replication.

Distribution of human enterovirus 71 in brainstem of infants with brain stem encephalitis and infection mechanism / 法医学杂志

OBJECTIVE@#To explore the mechanism that how human enterovirus 71 (EV71) invades the brainstem and how intercellular adhesion molecules-1 (ICAM-1) participates by analyzing the expression and distribution of human EV71, and ICAM-1 in brainstem of infants with brain stem encephalitis.@*METHODS@#Twenty-two brainstem of infants with brain stem encephalitis were collected as the experimental group and 10 brainstems of fatal congenital heart disease were selected as the control group. The sections with perivascular cuffings were selected to observe EV71-VP1 expression by immunohistochemistry method and ICAM-1 expression was detected for the sections with EV71-VP1 positive expression. The staining image analysis and statistics analysis were performed. The experiment and control groups were compared.@*RESULTS@#(1) EV71-VP1 positive cells in the experimental group were mainly astrocytes in brainstem with [dark]-brown particles, and the control group was negative. (2) ICAM-1 positive cells showed [dark]-brown. The expression in inflammatory cells (around blood vessels of brain stem and in glial nodules) and gliocytes increased. The results showed statistical difference comparing with control group (P < 0.05).@*CONCLUSION@#The brainstem encephalitis can be used to diagnose fatal EV71 infection in infants. EV71 can invade the brainstem via hematogenous route. ICAM-1 may play an important role in the pathogenic process.

Assessment of Porcine Reproductive and Respiratory Syndrome Virus RNA Load in Sera and Tissues during Acute Infection

Porcine reproductive and respiratory syndrome virus (PRRSV) RNA load in sera and tissues during acute phase of infection was evaluated using a PCR- based quantitative assay. More than 80% of infected pigs (21/25) showed the peak level of viral RNA concentrations in serum (up to 8.6 x 108 copies/ml) at day 5 postinfection (PI), and started to clear the virus from the systemic circulation thereafter. Regression analysis using the viral RNA concentrations in sera obtained from days 5 to 14 PI showed that the viral RNA was cleared at the rate of 0.37 log reduction in the number of PRRSV RNA copies per day. It was estimated to be day 27 PI when the viral RNA in the serum of infected pigs becomes undetectable. When correlation analysis was performed between the systemic clearance rate and viral RNA concentrations in tissues of 9 infected pigs obtained at day 14 PI, moderately strong negative correlation was observed in the thymus (r = - 0.62) and brain stem (r = - 0.48), suggesting the capability of host animal to clear PRRSV from the systemic circulation appears to be related to the viral activity in the thymus and brain stem.

Localization of Porcine Reproductive and Respiratory Syndrome Virus Infection in Boars by In Situ Riboprobe Hybridization

The capability of porcine reproductive and respiratory syndrome virus (PRRSV) to be shed in semen for extended periods of time has been suggested to be a principal factor for viral transmission via insemination. In attempts to gain insights into the mechanism of PRRSV persistence in boars, tissue distribution and sites of viral infection were investigated by in situ hybridization (ISH) using digoxigenin-labeled RNA probe and the ISH results were compared with those of reverse transcription-nested polymerase chain reaction (RT-nested PCR). Animals were intranasally inoculated with 104 median tissue culture infectious dose of PRRSV VR-2332 and tissues collected at different times were examined. At day 7 postinfection, limited number of hybridization positive signals was observed in cells within or between seminiferous tubules in the testis sections while relatively abundant hybridization positive signals were observed in the brain stem and tracheobronchial lymph node. At later days of infection, hybridization positive signals were observed in cells within seminiferous tubules with much reduced frequency. Lack of agreement with the RT-nested PCR assay results in testis tissues obtained at days 14, 28, and 59 postinfection suggested that PRRSV infection in the testis may be extremely restricted, and may not necessarily constitute a major viral source in semen during extended periods of seminal shedding.