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  • Author or Editor: Laurel J. Gershwin x
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SUMMARY

Immunoglobulin E is produced in response to parasitic nematodes that undergo blood and tissue migrations. Results of our previous studies indicated that IgE and IgG respond to Dirofilaria immitis in experimentally infected dogs. To determine the association between treatment with the larvicide, diethyl-carbamazine (dec), and antibody responses and to examine the potential influence of infection with a nonfilarid intestinal nematode on isotype-specific immune responses, we monitored, by use of isotype-specific elisa, separate IgE and IgG responses against D immitis in 4 groups (A-D) of 8 dogs experimentally coinfected with D immitis and Ancylostoma caninum. All dogs were monitored from 2 weeks before inoculation with D immitis, through postinoculation (pi) week 20. Group-B dogs received a daily regimen of 6.6 mg of dec/kg of body weight. Group-C dogs received 4.95 mg of oxibendazole/kg daily. Group-D dogs received dec and oxibendazole, equivalent to the daily doses given to dogs of groups B and C. All dogs given oxibendazole had no A caninum at necropsy. Of the groups receiving dec, 3 group-B dogs each had 1 to 2 D immitis at necropsy. When results of chronologic IgE determination for all groups were statistically compared, only groups B and C had significant (P = 0.0148 and P ≪0.00005, respectively) increases in IgE values. Group-C dogs had the highest IgE values from pi week 10 until the end of the study, whereas IgG values were statistically identical to those of group-A dogs. Group-B dogs given only dec and having the least number of D immitis of all groups, had IgE values that peaked at pi week 6; values were significantly (P = 0.0002) higher than those for all other groups. In Group-B dogs, IgG values increased significantly (P ≪ 0.00005) only at pi week 20 and were significantly (P ≪ 0.00005) decreased after pi week 6, compared with values for all other groups. Group D containing 6 dogs infected with 1 to 18 D immitis found at necropsy had IgE values between those of group-B dogs and those of nondec-treated groups at pi week 6. There was no difference in IgG values between 3 groups at pi week 6, and IgE values were found to be a better correlator than were IgG values to the number of D immitis larvae killed in the tissues during this period. All differences in IgG and IgE values not only correlated with treatment status and number of D immitis adults found at necropsy, but also with the developmental stage of D immitis commonly present in the groups at each time point and the number of adult D immitis found at necropsy.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To develop a system for analysis of immune response variables in the lymph draining the lung and to establish baseline data for clinically normal calves.

Design

Surgery was performed on 6 calves to insert a cannula into the efferent lymphatic duct of the caudal mediastinal lymph node to create a long-term thoracic lymph fistula draining to the exterior. Lymph was collected daily, and on the fifth postoperative day, calves were exposed to an aerosol of cell culture medium (mock infection). For the next 10 days, lymph was collected for analysis and, on the tenth day, necropsy was performed.

Animals

Six 6- to 8-week-old Holstein bull calves.

Procedures

Daily lymph samples were evaluated for: flow rate; total and differential cell counts; and IgG, IgM, IgA, IgE, and protein concentrations. On days −4, −1, 1, 4, 7, and 10, cells were stained and quantitated by fluorescence-activated cell sorter analysis for T, B, CD4+, and CD8+ cells. Blood lymphocytes were evaluated on days -1 and 10 for comparison.

Results

Flow was established for up to 25 days, with a mean rate between 11 and 22 ml/h. Protein concentrations in lymph and plasma did not indicate a protein drain. Although mean lymphocyte counts reflected a slight gradual decrease in lymph lymphocytes, this effect was not apparent in every calf, nor was the effect seen in blood lymphocytes. There were no significant changes in IgG, IgM, IgA, or IgE concentration, with the exception of IgA concentration in 1 calf that developed an abscess at the cannulation site. The T-cell subset absolute numbers of CD4+ and CD8+ cells decreased slightly over time, but the CD4+-to-CD8+ cell ratio remained almost constant at near 2.

Conclusions

Creation of a thoracic lymphatic fistula appears to be a useful technique for studying effects of lung infection on immunologic variables, with potential application to bacterial and viral respiratory tract diseases.

Clinical Relevance

Thoracic lymphatic cannulation can be used in studies to determine pathogenic mechanisms in respiratory tract disease and to develop more effective vaccines against respiratory tract pathogens.

Free access
in American Journal of Veterinary Research