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in Journal of the American Veterinary Medical Association

Summary

An experimental model of keratoconjunctivitis sicca (kcs) was produced by removing the lacrimal gland and the gland of the third eyelid from the left eye of 6 cats. The right eye of each cat was left intact and used as a control. After 2 weeks, cats were euthanatized and the central portion of the upper eyelid from both eyes of each cat was excised. Histologic sections were stained with either hematoxylin and eosin or with a battery of biotinylated lectins including concanavalin A (cona), soybean agglutinin (sba), wheat germ agglutinin (wga), succinylated wheat germ agglutinin (s-wga), Ulex europaeus agglutinin I (uea), Dolichos biflorus agglutinin (dba), Ricinus communis agglutinin (rca), peanut agglutinin (pna), and pna pretreated with neuraminidase.

Consistent differences in histologic features were not observed between conjunctivas with kcs and control conjunctivas. A variable degree of mononuclear cell infiltration of the substantia propria was observed in control conjunctivas and those with kcs. In both groups, conjunctival goblet cell density decreased and epithelial stratification increased as the degree of submucosal inflammatory cell infiltration increased.

Lectin binding sites for dba, wga, s-wga, uea, pna, and pna pretreated with neuraminidase were detected on conjunctival goblet cells of conjunctivas with kcs and control conjunctivas. The mucus/glycocalyx layer of conjunctival epithelial cells in both groups of conjunctivas bound lectins rca, wga, uea, and cona, but inconsistently bound s-wga. In both groups, dba principally bound to the mucus layer overlying normal epithelium, whereas pna pretreated with neuraminidase consistently bound to the mucus layer of stratified epithelial surfaces free of goblet cells. Binding of sba to goblet cells and the mucus/glycocalyx layer was variable.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine efficacy of a modified-live virus (MLV) vaccine containing bovine viral diarrhea virus (BVDV) 1a and 2a against fetal infection in heifers exposed to cattle persistently infected (PI) with BVDV subtype 1 b.

Animals—50 heifers and their fetuses.

Procedures—Susceptible heifers received a placebo vaccine administered IM or a vaccine containing MLV strains of BVDV1a and BVDV2a administered IM or SC. On day 124 (64 to 89 days of gestation), 50 pregnant heifers (20 vaccinated SC, 20 vaccinated IM, and 10 control heifers) were challenge exposed to 8 PI cattle. On days 207 to 209, fetuses were recovered from heifers and used for testing.

Results—2 control heifers aborted following challenge exposure; both fetuses were unavailable for testing. Eleven fetuses (8 control heifers and 1 IM and 2 SC vaccinates) were positive for BVDV via virus isolation (VI) and for BVDV antigen via immunohistochemical analysis in multiple tissues. Two additional fetuses from IM vaccinates were considered exposed to BVDV (one was seropositive for BVDV and the second was positive via VI in fetal tissues). A third fetus in the SC vaccinates was positive for BVDV via VI from serum alone. Vaccination against BVDV provided fetal protection in IM vaccinated (17/20) and SC vaccinated (17/20) heifers, but all control heifers (10/10) were considered infected.

Conclusions and Clinical Relevance—1 dose of a BVDV1a and 2a MLV vaccine administered SC or IM prior to breeding helped protect against fetal infection in pregnant heifers exposed to cattle PI with BVDV1b.

Full access
in American Journal of Veterinary Research