Ml. Anderson et al., IMMUNE AND INFLAMMATORY RESPONSES TO REPRODUCTIVE-TRACT INFECTION WITH TRITRICHOMONAS-FETUS IN IMMUNIZED AND CONTROL HEIFERS, The Journal of parasitology, 82(4), 1996, pp. 594-600
Histopathologic changes and local antibody responses were studied in i
mmunized and control heifers after intravaginal challenge with 10(6) T
ritrichomonas foetus. Animals were given 3 intramuscular inoculations
of immunoaffinity-purified superficial antigen, TF 1.17, in 2 differen
t adjuvant combinations (incomplete Freund's adjuvant or dextran sulfa
te plus IFA-8 animals each) or adjuvant alone at 3-wk intervals and we
re challenged with T. foetus 2 wk later. Histologically, a nonsuppurat
ive endometritis with nodular lymphoid aggregates in the stratum spong
iosum was present in 9 of 24 heifers. Twice as many control heifers as
immunized had moderate to severe endometritis at 10 wk and the rate o
f clearance of the organism was significantly faster in immunized than
in control heifers. Furthermore, time of clearance was statistically
correlated with severity of endometritis at 10 wk postinfection, when
necropsies were done (P < 0.02). Because 9-10 wk postinfection is thou
ght to be the critical period for determining fetal loss associated wi
th endometritis, this correlation with early clearance is important to
protection against disease. In heifers with moderate to severe infilt
ration of mononuclear cells in the endometrium, lymphoid nodules and s
ome secondary follicles were detected. In the subgroup of 12 animals f
rom which uterine secretions were collected, IgA antibody responses to
antigen were detected by 6 wk in infected animals with increases in m
ean responses at 8 and 10 wk, but not in uninfected animals. A rationa
le is presented for consideration of the lymphoid nodules as a possibl
e inductive site for this local antibody response to T. foetus.