Rh. Bondurant et al., SEROLOGICAL RESPONSE TO IN-VITRO SHED ANTIGEN(S) OF TRITRICHOMONAS-FETUS IN CATTLE, Clinical and diagnostic laboratory immunology, 3(4), 1996, pp. 432-437
We developed a serological assay for detection of (i) an erythrocyte-a
dhering molecule(s) shed by the bovine venereal pathogen Tritrichomona
s foetus and (ii) serum antibodies to this antigen(s) in exposed cattl
e. Sera from exposed and unexposed cattle were tested for their abilit
y to induce complement-mediated lysis of bovine erythrocytes that had
been previously incubated overnight at room temperature in pH-adjusted
supernatants of T, foetus culture media. Eight of 180 serum specimens
from six groups of presumably unexposed cows or heifers showed a posi
tive (greater than or equal to 1:2) hemolytic titer (specificity = 95.
6%). Thirteen of 14 females in two experimentally infected groups show
ed a positive hemolytic titer following infection (sensitivity = 94%).
In experimentally infected heifers, there was little correlation (r(2
) = 0.33) between serum hemolytic titers with respect to shed antigen
and titers obtained in serum enzyme-linked immunosorbent assays in whi
ch whole T. foetus served as the antigen. Serum hemolytic titers rose
3 to 4 weeks sooner than did previously described vaginal mucus immuno
globulin G1 or immunoglobulin A titers with respect to whole cell anti
gen or TF1.17 subunit antigen, respectively. Among 14 chronically infe
cted bulls, only 6 (43%) showed a positive hemolytic titer. This study
is the first, to our knowledge, to show a specific serological respon
se in the host to an in vitro-shed antigen(s) of T, foetus and suggest
s a useful diagnostic test for potentially exposed herds.