https://www.selleckchem.com/products/isa-2011b.html LW rats with (LWxDA) CTTI rejected the third-party BN hearts (mean survival time 10d; n=5). Controls did not (n=5). CTTI recipients produced antibody against third party BN donor but not against the DA thymus donor demonstrating humoral donor-specific tolerance. Taken together, F1(LWxDA) CTTI given to Lewis rats resulted in specific tolerance to the allogeneic DA MHC expressed in the donor thymus with resulting long-term survival of DA heart transplants after withdrawal of all immunosuppression.BACKGROUND The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a novel viral pneumonia (COVID-19), which is rapidly spreading in the world. The positive result of nucleic acid test is a golden criterion to confirm SARS-CoV-2 infection, but the detection features remain unclear. METHODS We performed a retrospective analysis in 5,630 high-risk individuals receiving SARS-CoV-2 nucleic acid tests in Wuhan, China, and investigated their characteristics and diagnosis rates. RESULTS The overall diagnosis rate was 34.7% (1,952/5,630). Male (P = 0.025) and older age (P = 2.525 × 10-39) were two significant risk factors of SARS-CoV-2 infection. People were generally susceptible, and most cases concentrated in people of 30- to 69-years-old. Besides, we investigated the association between diagnosis rate and the number of testing in 501 subjects. Results revealed a 1.27-fold improvement (35.5%/27.9%) of diagnosis rate from testing once to twice (P = 5.847 × 10-9), and a 1.43-fold improvement (39.9%/27.9%) from testing once to three times (P = 7.797 × 10-14). More than three testing times was not helpful for further improvement. However, this improvement was not observed in subjects with pneumonia (P = 0.097). CONCLUSION All populations are susceptible to SARS-Cov-2 infection, and male and older age are two significant risk factors. Increasing the number of testing could significantly improve diagnosis rates, exce