<prompt> Paul Bunnell antibodies are reactive in all except:OxSheepDogHorse  <response>: Ans. is a i.e., OxRef: Ananthanarayan, 9the, p. 109, 476 and 8the, p. 108, 477; Harrison, 18the, p. 1469, 1470; 19the, p. 1189 In infectious mononucleosis, Paul Bunnel heterophile antibodies are produced. These IgM class antibodies have an affinity for sheep, horse and bovine erythrocyte and a titre of 40 is diagnostic of acute EBV infection. Because these heterophile antibodies are adsorbed by ox red cells, they are not reactive in Ox Ox red cells remove these antibodies. Monospot test is more sensitive and specific than Paul Bunnel test. EBV specific antibody testing is used for patients, Titers of IgM and IgG abs to Viral capsid antigen VCA are elevated in 90 of patients at the onset of disease. Abs against EBNA are also demonstrated. EA - D abs are found in severe disease by EBV. Nowadays EBV DNA are demonstrated by PCR. 