Establishment of a peptide-based enzyme-linked immunosorbent assay for detecting antibodies against PRRSV M protein.

BACKGROUND: Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically devastating diseases affecting the swine industry globally. Evaluation of antibody responses and neutralizing antibody titers is the most effective method for vaccine evaluation. In this study, the B cell line epitopes of PRRSV M protein were predicted, and two peptide ELISA assays were established (M-A110-129 ELISA, M-A148-174 ELISA) to detect antibodies against PRRSV M protein. Field serum samples collected from pig farms were used to validate the peptide ELISA and compare it with an indirect immunofluorescence assay. RESULTS: The sensitivity and specificity of M-A110-129 ELISA and M-A148-174 ELISA were (111/125) 88.80%, (69/70) 98.57% and (122/125) 97.60%, (70/70) 100%, relative to indirect immunofluorescence assay. This peptide ELISA could detect antibodies against different genotypes of PRRSV including type 1 PRRSV, classical PRRSV, HP-PRRSV, and NADC30 like PRRSV, but not antibodies against other common swine viruses. The results of ROC analysis showed that the area under the curve (AUC) of the M-A110-129 ELISA and M-A148-174 ELISA were 0.967 and 0.996, respectively. Compared the concordance of results using two peptide ELISA assays, the IDEXX PRRSV X3 Ab ELISA and a virus neutralization test, were assessed using a series of 147 sera from pigs vaccinated with the NADC30-like PRRSV inactivated vaccine. The M-A148-174 ELISA had the best consistency, with a Cohen's kappa coefficient of 0.8772. The concordance rates of the Hipra PRRSV ELISA kit, M-A110-129 ELISA and M-A148-174 ELISA in the field seropositive detection results were 91.08, 86.32 and 95.35%, relative to indirect immunofluorescence assay. CONCLUSIONS: In summary, compared with M-A110-129 ELISA, the PRRSV M-A148-174 ELISA is of value for detecting antibodies against PRRSV and the evaluation of the NADC30-like PRRSV inactivated vaccine, but the advantage is insufficient in serological early diagnosis.

A Retrospective Study from 2 Centers in China on the Effects of Continued Use of Angiotensin-Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers in Patients with Hypertension and COVID-19.

BACKGROUND Use of renin-angiotensin-aldosterone system inhibitors in coronavirus disease 2019 (COVID-19) patients lacks evidence and is still controversial. This study was designed to investigate effects of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) on clinical outcomes of COVID-19 patients and to assess the safety of ACEIs/ARBs medication. MATERIAL AND METHODS COVID-19 patients with hypertension from 2 hospitals in Wuhan, China, from 17 Feb to 18 Mar 2020 were retrospectively screened and grouped according to in-hospital medication. We performed 1: 1 propensity score matching (PSM) analysis to adjust for confounding factors. RESULTS We included 210 patients and allocated them to ACEIs/ARBs (n=81; 46.91% males) or non-ACEIs/ARBs (n=129; 48.06% males) groups. The median age was 68 [interquartile range (IQR) 61.5-76] and 66 (IQR 59-72.5) years, respectively. General comparison showed mortality in the ACEIs/ARBs group was higher (8.64% vs. 3.88%) but the difference was not significant (P=0.148). ACEIs/ARBs was associated with significantly more cases 7-categorical ordinal scale >2 at discharge, more cases requiring Intensive Care Unit (ICU) stay, and increased values and ratio of days that blood pressure (BP) was above normal range (P<0.05). PSM analysis showed no significant difference in mortality, cumulative survival rate, or other clinical outcomes such as length of in-hospital/ICU stay, BP fluctuations, or ratio of adverse events between groups after adjustment for confounding parameters on admission. CONCLUSIONS We found no association between ACEIs/ARBs and clinical outcomes or adverse events, thus indicating no evidence for discontinuing use of ACEIs/ARBs in the COVID-19 pandemic.