[Reaction of the complement fixation test on microtitration plates: application to the serology of myxomatosis. Comparative study of the results with the reaction of indirect immunofluorescence]. / Réaction de fixation du complément en plaques de microtitration: application à la sérologie de la myxomatose. Etude comparative des résultats avec la réaction d'immunofluorescence indirecte.

The authors describe a complement fixation technique on microtitration plates, using an antigen prepared from myxomas induced in rabbits. Compared with indirect immunofluorescence this technique was less cumbersome, more economical, easier to read and (as a conventional procedure) applicable in all laboratories. Results obtained with 165 serum samples tested by both methods showed good correlation and a specificity at least equal to that of indirect immunofluorescence. Taking into account its lower sensitivity, the positive threshold value for complement fixation under the described experimental conditions was a dilution of 1:4 (H50).

Detection of African swine fever virus by a biotinylated DNA probe: assay on cell cultures and field samples.

African swine fever virus was detected in various samples using a molecular hybridization technique. A fragment located in a constant area of the viral genome was biotin-labelled. This probe, when present at a concentration of 100 ng/ml of the hybridization solution, could detect 10 pg of target DNA immobilized on nitrocellulose with cellular DNA and RNA. The virus was evidenced after being passaged on monkey kidney cells, either 8 h post-inoculation (pi) if the multiplicity of infection (MOI) was at least 1 hemadsorbing unit (HAd) per cell, or 24 h later if the inoculum was diluted up to 10(-3) HAd per cell. When passaged on pig leukocytes with a MOI of 0.1 HAd per cell, the virus was evidenced 12 h pi, or 24 h pi with a MOI of 10(-2) HAd per cell. The probe did not hybridize with another DNA virus passaged on cells, neither did it react with non-infected blood or ham, but did so if African swine fever virus was resuspended with the samples. The spleen from uninfected pig and the lymph nodes from a pig which had died from hog cholera were found to be negative, whereas the spleen from a pig which had died of African swine fever was positive. These samples were also tested with a 32P-labelled probe whose sensitivity was 10-fold higher. A non-radioactive probe could be used both for the sensitive and specific diagnosis of African swine fever and the detection of the virus in an epidemiological survey.

[A serological study of the contagious equine metritis: comparison between indirect immunofluorescence, slow agglutination and complement fixation techniques (author's transl)]. / Sérologie de la métrite contagieuse de la jument: comparaison des réactions d'immunofluorescence indirecte, de séroagglutination lente et de fixation du complément.

Serological response of pony mares to contagious equine metritis is studied comparing three techniques: slow agglutination, complement fixation and indirect immunofluorescence. Sera were taken from pony mares vaccinated with a heat inactivated suspension of Haemophilus equigenitalis, from experimentally-infected pony mares and from healthy horses. All three reactions detected antibodies in vaccinated and infected animals. The highest titers are observed with vaccinated mares. Titers are low in infected animals. Antibodies detected by indirect immunofluorescence appeared sooner and persisted longer in diseased animals than agglutinating or complement fixing antibodies. Only indirect immunofluorescence revealed a new contamination of two mares following coitus with a stallion excreting H. equigenitalis. Indirect immunofluorescence must be recommended in diagnosis of contagious equine metritis and in detection of chronic carriers.