Experimental maedi infection in sheep, 2: Antibody response [maedi strain, slow viruses, complement fixing antibodies, neutralizing antibodies]

• Published in: Acta veterinaria scandinavica 1980-01, Vol.21 (1), p.124-133
• Main Authors: Sihvonen, L, Estola, T, Tuomi, J. (College of Veterinary Medicine, Helsinki (Finland). Dept. of Microbiology and Epizootology)
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Viral - analysis; Complement Fixation Tests; Pneumonia, Progressive Interstitial, of Sheep - immunology; Respiratory System - microbiology; Sheep - microbiology
• ISSN: 0044-605X; 1751-0147; 1751-0147
• DOI: 10.1186/BF03546907

All 4 sheep inoculated via the respiratory tract with 7 X 10('6) TCID50 of maedi M88 strain developed complement fixing (CF) antibodies within 3 months after inoculation, and a gradual rise in CF titers was found during the first year. The antibody titers have been maintained, though with some fluctiation, through the following year, and the titers vary from 64 to 256. Virus neutralizing activity against maedi M88 strain was detected in the sera of all intrapulmonarily inoculated sheep within 8 months after inoculation. Titers have been maintained or have slightly increased. The level of titers, ranging from 8 to 256, was clearly different between individual sheep. One of the 4 sheep inoculated intracerebrally with 5 X 10('5) TCID50 of maedi M88 strain developed CF antibodies 1 month after inoculation, but no neutralizing antibodies until death 11 months after inoculation. The rest of the intracerebrally inoculated sheep displayed no evidence of CF or neutralizing antibodies within 18 months after inoculation in spite of numerous virus isolations from peripheral blood leukocytes. The absence of antibodies might perhaps be attributed to phenomena such differences in tropism, provirus state, immunological tolerance and size of inoculum. One sheep hyperimmunized with repeated s.c. and i.v. injections of maedi M88 strain developed high CF antibody titers but lower meutralizing antibody titers. The 2 uninoculated control sheep developed no CF or neutralizing antibodies within 18 months after inoculation.