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A microtiter enzyme-linked immunosorbent fluorescence assay based on alkaline phosphatase conjugate and 4-methylumbelliferyl phosphate as fluorogenic substrate was developed and adapted to quantitatively analyze immunoglobulin G subclass 1 (IgGl) and IgG2 responses of vaccinated and infected cattle to proteins of Coxiella burnetii. The enzyme-linked immunosorbent fluorescence assay surpassed the conventional enzymelinked immunosorbent assay with a 50-fold-higher sensitivity and a broader range of linear dose-response signals. Antigens of C. burnetii were purified by sodium dodecyl sulfate extraction and molecular-sieve high-pressure liquid chromatography. The purified 14-, 27-, and 30-kilodalton proteins were used as antigens without any further treatment. Vaccination with either chloroform-methanol-extracted cell residues of C. burnetii or the 27-kilodalton major surface protein evoked an early IgG2 response to the 27-kilodalton protein (2 weeks after immunization), whereas IgG2 to lipopolysaccharides of C. burnetii was detected only in the late phase (13 weeks after immunization). These results may have implications for the serodiagnosis of acute and chronic Q fever. IgGl against these antigens was induced solely by naturally occurring C. burnetii infections, indicating that infected cattle can be distinguished from vaccinated cattle by using the enzyme-linked immunosorbent fluorescence assay and SP27 antigen.

Summary The development of antibody levels in colostrum and milk in 10 cows vaccinated twice subcutaneously in the dry period at an interval of 4 weeks with Lactovac® was investigated in a controlled study. Antibody levels to all five antigens involved were higher than those in 10 unvaccinated controls on days 1, 4, 7, 10 and 14 after calving. The degree of the increase differed from quota to quota and became smaller overall up to day 14. The greatest average increases were observed for the E. coli K 99 at 26.6 times higher on day 1, decreasing to 3.0 times on day 14. The lowest increases in antibody titre were observed for coronavirus at 1.5 times on day 1 and 1.8 times on day 14, and parvovirus at 3.0 and 1.2 times. Rotavirus antibodies were 12.8 (Holland strain) and 7.2 (strain 1005) times higher than controls on day 1, and on day 14 were 4.4 and 3.6 times higher respectively. Most of the differences were statistically significant. The different possibilities to detect efficacy of the vaccination of the dam are discussed. Zusammenfassung Antikörpertiter in der Milch gegen Erreger der neonatalen Diarrhoe bei geimpften und nicht geimpften Kühen In einem kontrollierten Versuch wurde der Verlauf spezifischer Antikörpertiter in Kolostrum und Milch von 10 Kühen, die zweimal während der Trockenstehphase im Abstand von 4 Wochen mit Lactovac® subkutan geimpft worden waren, untersucht. Für alle fünf enthaltenen Antigene ließ sich gegenüber 10 ungeimpften Kontrollen eine Steigerung der Milchantikörpertiter an den Tagen 1, 4, 7, 10 und 14 post partum zeigen. Die Steigerungsfaktoren differierten zwischen den einzelnen Quoten und nahmen zum Tag 14 hin überwiegend ab. Die höchsten durchschnittlichen Steigerungsfaktoren traten bei der E. coli K 99‐Quote auf mit 26,6 am Tag 1 bzw. 3,0 am Tag 14. Die geringste Steigerung der Antikörpertiter zeigten die Coronavirusquote mit 1,5 am Tag 1 und 1,8 am Tag 14 und die Parvovirusquote mit Faktor 2,0 bzw. 1,2. Die Rotavirus‐Antikörpertiter lagen am Tag 1 um den Faktor 12,8 (Stamm Holland) bzw. 7,2 (Stamm 1005), am Tag 14 um den Faktor 4,4 bzw. 3,6 über den Kontrollen. Die nachgewiesenen Unterschiede konnten in der Mehrzahl als statistisch signifikant gesichert werden. Die unterschiedlichen Ansatzpunkte für den Wirksamkeitsnachweis einer Muttertiervakzination werden diskutiert.