Immunoglobulins in sera and feces from Paratuberculosis infected cattle.

FERNÁNDEZ, B.; JOLLY, A; GILARDONI, L.; GOLDMAN, L.; COLAVECCHIA, S; FERNÁNDEZ, E.; MUNDO, S

Ghent

Congreso; 14th International Conference on Production Diseases in Farm Animals; 2010

Universiteit Gent

Paratuberculosis, caused by Mycobacterium avium subsp. paratuberculosis (Map), is a chronic granulomatous enteritis disease affecting ruminants causing mayor economic losses in the dairy industry worldwide. As infection progresses to a clinical state, bacterial shedding in feces and sera Immunoglobulin (Ig) titers increase. Generally, Ig response against mycobacterial infections has been considered non protective; however, this affirmation is nowadays under review. Our aim was to characterize systemic and local serological responses of cows in various stages of paratuberculosis infection. Eleven cows were classified as healthy control (C) and naturally infected: asymptomatic (A), symptomatic (S) and terminal (T) groups. Totals (Igt) and Map-specific (Ige) immunoglobulins isotypes from sera and feces were assessed by ELISA, using purified bovine IgG1 and IgG2 as reference, anti-bovine IgM, IgG1 and IgG2 (Bethyl inc.), recombinant IgG31 and rabbit sera anti-recombinant IgG31. Results were expressed as optical density or µg/ml and analyzed by ANOVA (p< 0.05). In sera: no differences were detected on IgGt total level among groups. Whereas, IgGe of S (0,69±0,04), and T (0,42±0,04) were significantly elevated compared with C (0,20±0,09). The analyze of subisotipes showed that IgG1e predominated in S and T (679±1 and 1160±3 µg/ml respectively).Besides, the levels of IgG2e and IgG3e were higher in all infected groups than in C. Surprisingly, IgG3e was the highest Ige in sera from A (19±9 µg/ml). In feces: levels of IgMt (0,11±0,04), IgGt (0,73±0,30) and IgGe (0,59±0,54) significantly increased in S. Also, IgG3e was the uppermost Ige detected in feces from A (10±1 µg/ml) and S (19±13 µg/ml). In conclusion, our results showed Igt levels in sera were not modified by the infection. The increment of Ig in feces could be caused by lesions of intestinal mucosa. The predominance of IgG1 in the symptomatic period is related to the change toward Th2 profile. To our knowledge, this is the first report that describes IgG3 in feces from Map-infected cows. The use of anti-IgG3 could improve the identification of asymptomatic cattle. 1 SL Mundo, 2008, Vet. Res., 39, 06.